Drug Discovery: Innovations, Challenges and the Future of Medicine

Credit: iStock DRUG DISCOVERY: Innovations, Challenges and the Future of Medicine SPONSORED BY How Is AI Speeding Pharma’s Journey Toward Precision Medicine? Navigating the Complexities of Impurities in Pharmaceuticals The Promise and Perils of Weight Loss Drugs CONTENTS 04 High-Throughput Screening: Advances, Applications and Combined Approaches 10 How Is AI Speeding Pharma’s Journey Toward Precision Medicine? 13 Integrating Complex In Vitro Models Into the Regulatory Pipeline 16 The Promise and Perils of Weight Loss Drugs 21 How Broadly Neutralizing Antibodies Are Driving Next-Gen Vaccines 29 Navigating the Complexities of Impurities in Pharmaceuticals 35 The Evolving Treatment Landscape for Alzheimer’s 39 Unveiling the Progress and Challenges in the Fight Against HIV 43 Contributors DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 3 TECHNOLOGYNETWORKS.COM FOREWORD The landscape of drug discovery is undergoing a remarkable transformation, driven by scientific breakthroughs, technological advancements and a growing demand for innovative treatments. With the rise of conditions such as Alzheimer's disease, HIV and obesity, researchers are accelerating efforts to develop therapies that are not only effective but also safer, more targeted and accessible to those in need. The journey from identifying a promising drug target to delivering a life-changing treatment is a complex and multidisciplinary endeavor. High-throughput screening, AI and in vitro models are revolutionizing early-stage research, while novel biologics and precision medicine approaches are shaping the future of patient care. Yet, challenges remain, from navigating regulatory pathways to addressing the risks and limitations of new therapies. This eBook brings together expert insights on the latest trends in drug discovery, from the potential of broadly neutralizing antibodies in vaccine development to the promise and perils of weight loss drugs. It also explores how AI is optimizing pharmaceutical research and how emerging therapies for neurodegenerative diseases and infectious conditions are redefining treatment possibilities. The Technology Networks editorial team 4 DRUG DISCOVERY High-throughput screening (HTS) is a drug discovery approach that involves screening vast libraries of small molecules to identify “hits” with therapeutic potential. As a result of exciting past scientific breakthroughs, HTS approaches have been miniaturized, standardized and automated. This, alongside more recent advances in cell culture and data analysis, has led to faster more reproducible screening with targets that more accurately reflect in vivo physiology. In this article, we highlight various HTS strategies being used to interrogate large libraries of compounds and hear from researchers working to further streamline specific approaches to increase speed and improve quality and accuracy. Let’s start by considering different approaches to HTS. In vitro biochemical assays A purified target (e.g., enzyme, receptor or hormone) is screened against a compound library. The readout is typically achieved using optical detection methods such as absorbance, fluorescence or luminescence. Considerations: These assays can identify hits and quantify binding affinity but cannot reproduce a phenotypic or functional response. They are unable to provide information on cellular context. Cell-based assays Increasingly cell-based assays are used to provide a phenotypic readout, e.g., a change in signaling measured by a reporter gene or an effect on cell growth. High-Throughput Screening: Advances, Applications and Combined Approaches Joanna Owens, PhD Credit: iStock TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 5 Considerations: They provide information on how compounds affect function in a cellular environment. However, drug compounds can sometimes fail to perform in this setting if 2D monolayer cultures are used, as they lack the native tissue microenvironment1 that influences cell behavior and function. These assays do not provide information on how the compound is exerting its effect – i.e., what the cellular target is, or whether it is hitting the desired target or not. RNA interference (RNAi) screening RNAi screening can be used for high-throughput analysis of gene function on a genome-wide scale.2 Considerations: This approach provides insights into functional networks in cells that could be targeted in drug discovery. It can be combined with high-content imaging. These approaches are key in the early stages of drug discovery, offering researchers a diverse set of tools that can be used in combination depending on the specific requirements of the project and starting materials (i.e., libraries, X-ray structures of targets, available disease models). They each have their own merits and limitations, but all have universally benefitted from several key technological advances (Table 1). Despite these advances, researchers are still working to optimize conventional HTS approaches and develop platforms and software to combine different methods. In the rest of this article, we’ll explore some examples of innovation in screening methods. Navigating challenges in HTS The practical logistics of screening compound libraries that can contain as many as three to four million compounds remains a major challenge in HTS. Automation HTS was made commercially feasible by the development of automated liquid handling workflows that make it time and cost-efficient to process thousands of parallel samples. Today’s automated workflows require limited supervision or manual intervention and improve screening quality and reproducibility.3,4 Microfluidic systems Miniaturized microfluidics devices make it possible to screen compounds in high-density arrays, using small volumes of purified target and compound.5 This has increased the rate of screening and reduced the amount of reagents required. Microfluidic channels also provide a basis for building different connected compartments to mimic the interconnected nature of the human body. 3-dimensional (3D) cell culture 3D cell culture has enabled tissue spheroids or miniature organs (organoids) to be derived from cell lines, primary cells or stem cells, which further enhance drug screening by better recapitulating the human physiological environment compared to 2D cell lines or animal models.6 High content screening The addition of automated and/or live cell imaging methods alongside quantitative assays now makes it possible to capture more detailed phenotypic outputs in high throughput, by taking multiple views of a well under different light wavelengths and by labeling different targets within the individual cells.7 This can provide insights into cellular expression changes, or morphology changes at the organelle or single-cell level. Multiple properties of individual cells can also be studied simultaneously. HCS assays are typically conducted using 2D monolayer cultures to achieve higher throughput. However, 3D cell culture systems (e.g., spheroids, organoids) can also be used. Gene editing Precise gene knockout using tools (e.g., CRISPR-Cas9) offer the potential to screen cells for targets that can then be pursued therapeutically.2,8 As CRISPR guides are very easy to synthesize, you can design customized libraries to knock out every gene in the genome or a particular set of genes, making the approach amenable to HTS. DNA-encoded libraries Advances in genetic sequencing allow compounds to be DNA barcoded, so that large compound libraries can be screened within a single microplate well, accelerating hit identification and optimization.9,10 TABLE 1: Key advances in assay technologies for HTS TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 6 Physically screening each of these compounds against a single target in replicate is a time-consuming and laborintensive undertaking, even with automation. Using more focused libraries for well-characterized targets is one option, but another route is to use mixtures of compounds against a single target. To achieve this, compounds can be attached to solid substrates such as beads to allow the purification of “hits”, but this is still not practical for the largest libraries. This has led to the introduction of DNA barcoding to generate DNAencoded libraries. Dr. Basilius Sauter is a postdoctoral researcher in Prof. Dennis Gillingham’s lab at the University of Basel. Sauter specializes in the areas of DNA-encoded libraries and DNA-modifying drugs. “Although the concept of DNA barcoding is not new, it was only with advances in next-generation sequencing that DNA-encoded libraries became viable for larger library sizes,” he said. “Since then, the number of different chemistries available has rapidly increased, allowing the generation of more diverse DNA-encoded libraries covering a greater chemical space.” Optimizing DNA-encoded libraries for HTS One limitation of DNA-encoded libraries is that, unlike conventional HTS, the assay can only detect binders or non-binders, and you need to be able to separate these. The conventional method is to use an affinity purification step, where you attach your target protein to a solid phase and wash the non-binders away. But this has the disadvantage that you can lose compounds that bind weakly which, with further optimization, could have been potential drug candidates. To circumvent this, Sauter and colleagues have recently developed a new technique using an enzyme called terminal deoxynucleotidyl transferase (TDT). “TDT is a very special polymerase because it can synthesize DNA without a template,” explained Sauter. “We made a fusion of TDT with our target protein of interest, such that when a DNA-encoded library member binds to the protein of interest, TDT is in close proximity. Then, when we incubate with only dATP, the TDT preferentially extends the 3’ terminus of the DNA barcode on the hit molecule and makes a long poly dA tail.” This makes it possible to select hits in solution, which is an advantage when working with drug targets that start to denature or behave differently when on a solid phase for the affinity purification step. The polyA tail is also proportionate to the binding affinity of the compound, because it relies on the proximity of the drug to the target.11 Perhaps the most exciting and surprising result, however, was that the TDT method not only identified all the binders that were determined using the standard affinity purification step, but also found additional weak binders that had evaded previous screens. “When we tested it, it turned out to be a very weak inhibitor of our target molecule,” said Sauter.” One of the issues with DNA-encoded libraries is they often identify hits that are strong binders but it’s not possible to take them forward because they aren’t amenable to lead optimization by medicinal chemists. We want to DNA-encoded libraries A short piece of DNA called a “headpiece” is split into portions and modified with different small molecules.9 A set of unique DNA barcodes is added to each portion of DNA, with each barcode corresponding to a specific small molecule. The resulting DNAchemical conjugates are then pooled, split, chemically diversified and encoded with another set of DNA barcodes. This splitmodify-encode-pool is usually repeated 2-4 times and allows the generation of many thousands of DNA-encoded small molecules that can be screened against a protein target. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 7 build on the work we’ve done so far to find a screening assay that is sensitive for these weak binders, especially for difficult targets where having a weak interaction is better than none.” Combining different screening approaches and considering alternatives Selecting a specific HTS approach often involves a compromise between using a method that provides fundamental information about drug binding characteristics to determine (e.g., specificity and sensitivity) and gaining functional insights about whether a drug’s action is achieving the desired phenotypic results. To solve this problem, a team led by Pavel Levkin at the Karlsruhe Institute of Technology (KIT) in Germany has developed a combined highcontent, high-throughput platform that enables unified on-chip chemical synthesis, characterization and biological screening.12 The chip was developed as part of a European Research Council Proof-of-Concept project to develop more affordable and faster cell screening experiments in diagnostics and personalized medicine. Levkin and colleagues developed dendrimer-based surface patterning that enables the generation of high-density nanodroplet arrays. Each of the 50,000 droplets on a plate function as an individual nanovessel. With these vessels it is possible to conduct combinatorial chemical synthesis and then run a range of analytical assays – from on-chip detection using methods such as infrared spectroscopy or matrix-assisted laser desorption/ ionization mass spectrometry, to high-content cellbased screening. By bringing together the traditionally separate steps of high-throughput chemical synthesis, reaction monitoring, compound characterization and biological screening, the technique offers the potential to unify the different approaches used in early-stage drug discovery. Another significant challenge in HTS is managing large compound libraries and this, together with more challenging targets, has led drug discovery researchers to adopt fragment-based drug discovery (FBDD) as an alternative to HTS. In FBDD you initially screen chemical “fragments” to identify those with promising functionality, and then build on the fragment “hit” either by adding other chemistries or combining several fragments to create a more potent lead compound. Pioneered in the late 1990s by Professor Steve Fesik as “SAR by NMR”, it now constitutes an essential toolkit for the biopharma industry.13 However, despite this sensitivity, NMR screening has other limitations – researchers screening libraries of thousands of compounds quickly find themselves with a data analysis bottleneck, having to visually inspect thousands of spectra. To address this problem, Geerten Vuister, professor of structural biology at Leicester University and chair of the Collaborative Computational Project for NMR and his team have developed a computational pipeline of analysis tools to support NMR-based screening.14 It started with tackling a fundamental challenge – the complexity of a fragment library. “Even relatively small fragment libraries contain several hundreds of compounds and each has its own NMR spectrum, so when you combine these molecules in a single mixture, you might get overlapping spectral regions and it becomes difficult to distinguish between them,” explained Dr. Luca Mureddu, who developed the pipeline. “Moreover, factors such as experimental error, degradation of library compounds and varying buffer requirements for different protein targets all contribute to considerable variability between spectra.” This led them to develop tools and workflows that adjust for experimental factors and post-processing that deals with the variability of the data improving the hit rate identification. After running the algorithms of the workflow, which can take as little as seconds for a small library, to around ten minutes for a library of a few thousand compounds, users receive a set of scores indicating a level of confidence about whether a compound is a hit or not. “The most important premise is that we don’t want to replace the researcher,” said Mureddu. “So, we don’t provide a binary yes/no answer to whether something is a hit.” Instead, based on a combination of scores, users can not only identify reliable positive or negative hits, but also TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 8 easily inspect the data for compounds that fall into the “uncertain” zone, potentially prioritizing these for followup screening using another established method. “Drug companies tend to use a variety of screening approaches, so it was important to develop a pipeline that users can customize to their own specific screening needs,” highlighted Dr. Vicky Higman, a Research Fellow in Vuister’s team specializing in NMR. “We’ve already seen that our collaborators are increasing the size of their screening libraries, because they can now analyze data much more quickly and reliably.” • ABOUT THE INTERVIEWEES Dr. Basilius Sauter is a postdoctoral researcher in Professor Dennis Gillingham’s lab at the University of Basel. Sauter specializes in the areas of DNA-encoded libraries and DNAmodifying drugs. Dr. Luca Mureddu is a postdoctoral researcher at the University of Leicester and part of the Collaborative Computational Project for NMR working group. Mureddu focuses on focus on developing software tools for fragment based-screening to enable and accelerate high quality and reproducible research. REFERENCES 1. Wei F, Wang S, Gou X. A review for cell-based screening methods in drug discovery. Biophys Rep. 2021;7(6):504- 516. doi: 10.52601/bpr.2021.210042 2. Taylor J, Woodcock S. A perspective on the future of high-throughput RNAi screening: Will CRISPR cut out the competition or can RNAi help guide the way? J Biomol Screen. 2015;20(8):1040-1051. doi:10.1177/1087057115590069 3. Hansel CS, Plant DL, Holdgate GA, Collier MJ, Plant H. Advancing automation in high-throughput screening: Modular unguarded systems enable adaptable drug discovery. Drug Discov Today. 2022;27(8):2051-2056. doi: 10.1016/j.drudis.2022.03.010 4. Green CP, Spencer PA, Sarda S. Advancing automation in compound management: a novel industrial process underpinning drug discovery. Drug Discov Today 2021;26(1):5-9. doi: 10.1016/j.drudis.2020.09.032 5. De Stefano P, Bianchi E, Dubini G. The impact of microfluidics in high-throughput drug-screening applications. Biomicrofluidics. 2022;16(3):031501. doi: 10.1063/5.0087294 6. Wang Y, Jeon H. 3D cell cultures toward quantitative high-throughput drug screening. Trends Pharmacol Sci. 2022;43(7):569-581. doi: 10.1016/j.tips.2022.03.014 7. Blay V, Tolani B, Ho SP, Arkin MR. High-throughput screening: today's biochemical and cell-based approaches. Drug Discov Today. 2020;25(10):1807-1821. doi: 10.1016/j.drudis.2020.07.024 8. Shalem O, Sanjana NE, Zhang F. High-throughput functional genomics using CRISPR-Cas9. Nat Rev Genet. 2015;16(5):299-311. doi: 10.1038/nrg3899 9. Satz AL. What do you get from dna-encoded Libraries?. ACS Med Chem Lett. 2018;9(5):408-410. doi: 10.1021/ acsmedchemlett.8b00128 10. Reddavide FV, Cui M, Lin W, et al. Second generation DNA-encoded dynamic combinatorial chemical libraries. Chem Commun (Camb). 2019;55(26):3753-3756. doi: 10.1039/c9cc01429b 11. Schneider LA, Sauter B, Dagher K, Gillingham D. Recording binding information directly into DNA-encoded libraries using terminal deoxynucleotidyl transferase. J Am Chem Soc. 2023;145(38):20874-20882. doi: 10.1021/ jacs.3c05961 12. Benz M, Asperger A, Hamester M, et al. A combined highthroughput and high-content platform for unified on-chip synthesis, characterization and biological screening. Nat Commun. 2020;11:5391. doi: 10.1038/s41467-020-19040-0 13. Shuker SB, Hajduk PJ, Meadows RP, Fesik SW. Discovering high-affinity ligands for proteins: SAR by NMR. Science. 1996;274(5292):1531-1534. doi: 10.1126/ science.274.5292.1531 14. Mureddu LG, Ragan TJ, Brooksbank EJ, Vuister GW. CcpNmr AnalysisScreen, a new software programme with dedicated automated analysis tools for fragment-based drug discovery by NMR. J Biomol NMR. 2020;74(10-11):565- 577. doi: 10.1007/s10858-020-00321-1 The most revolutionary serological pipet controller integra-biosciences.com PIPETBOY GENIUS Brings color into your lab! Overfill protection Aliquot faster, aspirate safer, pipet smarter. Lightning-fast, one-button repeat dispensing of aliquots 10 DRUG DISCOVERY While generative artificial intelligence (AI) burst into the public consciousness a little more than two years ago with the release of ChatGPT, AI and machine learning (ML) have been part of drug research and development for far longer. AI and ML are now being applied to every stage of biopharmaceutical R&D including discovery, compound development, trial design, regulatory submission, supply-chain optimization and postmarket surveillance. In the last two years, several published, peer-reviewed articles have referred to precision medicine as “futuristic” – a state that has not yet been fully realized – but drug discovery is rapidly becoming more patientcentered with each new application of AI. Although ChatGPT and other generative AI engines built into smartphones, Internet search engines and social media platforms have captured public attention, generative AI is only one flavor of the technology. The pharma industry has been using predictive modeling for years. Investigators are turning to increasingly advanced algorithms to identify patient subgroups, forecast mechanisms of action, predict differential drug responses including toxicity and even adjust dosing strategies. How Is AI Speeding Pharma’s Journey Toward Precision Medicine? Neil Versel Credit: iStock TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 11 Popular use cases and therapeutic areas In a 2023 report, the UK-based Wellcome Trust identified five key families of use cases for AI in drug discovery: • Drug target identification and validation • Small-molecule design and optimization by pinpointing “hit-like or lead-like small molecule compounds” • Design and optimization of vaccines, particularly mRNA vaccines • Design and optimization of antibody structures and properties • Evaluation of safety and toxicity of promising compounds According to the report, more than 80% of published articles on AI-enabled drug discovery in the preceding five years were related to understanding disease, target discovery and optimization of small-molecule compounds. Of note, the organization said there has been a dearth of publicly available data on safety and toxicity to train AI models. Interviews with experts in the field included in the report mentioned the challenges of predicting safety and toxicity based on in silico data without sufficient supporting clinical validation. The Wellcome report also cited a 2021 Nature article describing how AlphaFold, an AI/ML algorithm from Google sister company DeepMind, predicted the three-dimensional structure of human proteins with “atomic” accuracy. About 70% of private-sector investments in AI for drug discovery between 2018 and 2022 were in the “commercially tractable” therapeutic areas of oncology, neurology and COVID-19, Wellcome added. As noted in the American Journal of Managed Care (AJMC), numerous drug companies have already incorporated AI into drug R&D processes, particularly to improve target identification, molecule discovery and patient recruitment for trials. “The integration of AI into the drug discovery process offers immense potential for accelerating drug development, reducing costs, and improving patient outcomes,” the October 2024 article concluded. “However, the successful implementation of AI requires addressing knowledge gaps, ensuring data quality, and navigating regulatory challenges.” At least one major drug company has said that it is looking at AI for developing precision therapeutics in oncology, immunology and neuroscience, all popular therapeutic areas for AI application among Big Pharma. However, the Wellcome report cited COVID-19 response as a shining example of the power of this evolving technology. In the early days of the pandemic in March 2020, AI was used to research monoclonal antibodies derived from convalescent plasma of COVID-19 patients. About 2,000 potential candidates were quickly narrowed down to 24, and the most promising compound, bamlanivimab, entered into clinical trials within three months. The U.S. Food and Drug Administration (FDA) granted Emergency Use Authorization to bamlanivimab in November 2020, just eight months after research commenced. Though the FDA revoked the authorization in April 2021 after subsequent SARS-CoV-2 variants proved more resistant to the therapy, this episode highlighted just how rapidly drug-makers could develop narrowly targeted treatments. Reality and promise AI analyzes large genomic and multiomic datasets faster than ever before to help target therapies. A study published in Science in September 2023 explained how bioinformaticians have been able to build upon each other’s work to extend the capabilities of popular AI algorithms including AlphaFold to improve prediction of pathogenicity of missense variants in the human proteome. A May 2024 review article published in the journal Fundamental Research suggested that AI, in the form of unsupervised machine learning, is a more efficient way of generating patient clusters and phenotype candidates than human training of datasets in the development of gene therapies. AI is also useful for optimizing drug TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 12 dosing based on individuals’ genetic profiles, the international team of authors wrote. A July 2023 article in Pharmaceutics noted that an AI technique called clustering – which groups similar datapoints to find subgroups of patient data, gene expression profiles, chemical structures and other pertinent information – is useful for identifying drug targets and stratifying patients. Other AI algorithms can sift through complex stores of data in search of anomalies. “AI is being utilized to advance precision medicine approaches. By analyzing patient data, including genomics, proteomics, and clinical records, AI algorithms can identify patient subgroups, predict treatment responses, and assist in personalized treatment decision-making. AI also contributes to the development of biomarkers for disease diagnosis and prognosis,” the authors, academic researchers from India and Northern Ireland, wrote. “AI might revolutionize the pharmaceutical industry in the future to accelerate drug discovery and drug development,” they continued, offering a clear caveat with their word choices. “AI-enabled precise medicine could categorize patients, predict therapy responses, and customize medicines by analyzing genomes, proteomes, and clinical records.” They saw promise in what they called “virtual screening” to accelerate identification of lead compounds by selecting therapeutic candidates with the necessary characteristics from massive chemical databases. “Scientists may create innovative compounds with target-binding characteristics using deep learning and generative models, improving medication effectiveness and lowering adverse effects,” the Pharmaceutics article said. “AI improves clinical trial design, patient selection, and recruitment. AI algorithms will use electronic health records, biomarkers, and genetic profiles to find appropriate patients, lower trial costs, and speed up approval.” But, as the AJMC article stated, AI performance is only as good as the data the algorithm is trained on — the old “garbage in, garbage out” maxim from computer science. One potential tripwire is data bias. Writing in NPJ Digital Medicine, investigators from the Berlin Institute of Health at Charité and Harvard Medical School noted that AI data is often trained on datasets that have under-represent women, people of color, lowincome groups and other historically disadvantaged demographics. “For example, an AI algorithm used for predicting future risk of breast cancer may suffer from a performance gap wherein black patients are more likely to be assigned as ‘low risk’ incorrectly,” they said. Regulation Regulation rarely keeps up with technological advancements, and AI is no different in this regard. While enabling legislation might be behind the times, regulators are at least attempting to stay ahead of the curve by offering guidance to constituents including drug developers. For example, the European Medicines Agency (EMA) recently spent more than a year developing a “reflection paper” offering guidance on using AI/ML in pharmaceutical discovery, development, approval submissions, manufacturing and outcomes assessment. This guidance document spells out how existing European Union and national laws cover AI/ML across pharma lifecycles, including when technologies might be treated as medical devices. The EMA pointed out the importance of paying attention to data quality and relevance in training algorithms. ML developers should take a “humancentric approach” to design be able to explain their methodologies to allow the agency to review and monitor “black box” models, the paper said. “This requires not only that active measures are taken during data collection and modelling … but also that both user and patient reported outcome and experience measures are included in the evaluation of AI/ML tools when they interface with an individual user or patient,” the EMA explained. • 13 DRUG DISCOVERY Complex in vitro models (CIVMs), such as microphysiological systems (MPS), organoids, spheroids and organ/tissue-on-a-chip, present an opportunity to enhance the efficiency and accuracy of drug discovery and development in an ethically manner. The Critical Path Institute (C-Path), a nonprofit organization created to improve drug development, has been working to facilitate the adoption of MPS as drug development tools (DDT) in regulatory science. At this year’s Society for Laboratory Automation and Screening (SLAS) annual meeting, Dr. Graham Marsh, scientific director at C-Path, presented the organization’s framework to support a US Food and Drug Administration (FDA) qualification of CIVMs for use in regulatory submissions. Technology Networks had the pleasure of speaking with Marsh to discuss how the framework was developed and how automation and AI can increase the confidence in CIVMs. Q: What is C-Path, and what are its core aims? A: C-Path's mission is to lead collaborations that advance better treatments for people worldwide. Globally recognized as a pioneer in accelerating drug development, C-Path has established numerous international consortia, programs and initiatives that currently include more than 1,600 scientists and representatives from government and regulatory agencies, academia, patient organizations, disease foundations and pharmaceutical and biotech companies. Integrating Complex In Vitro Models Into the Regulatory Pipeline Molly Coddington Credit: iStock TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 14 Uniquely different to a contract research organization or service provider, our neutral collaborations offer a unique front-row seat to the dialogue on the latest in regulatory science from FDA and the Europeans Medicines Agency. These collaborations allow for information and data sharing, which serves as the foundation for C-Path to spearhead the transformation of such information and data into actionable solutions that address specific unmet needs in the drug development process. Such solutions can include data resources, biomarkers, clinical outcome assessment tools, clinical trial simulators and other quantitative tools. Q: Can you discuss how CIVMs could supplement or even replace existing models? A: Regulatory agencies rely on models for demonstrating drug efficacy and safety. These models have gone through rigorous characterization to ensure confidence in the data that they produce. The stance of regulatory bodies – and I think rightly so – is to be conservative and cautious to choose the in vitro and in vivo data from models that has been qualified and routinely used when evaluating new drugs. At the same time, scientists are rapidly developing new methods that promise to better represent human biology. MPS bring multiple cell types together with relevant cell–cell interactions and shear forces, and more faithfully reproduce the biology observed in vivo. We have been working to bridge these two camps and enable the robust characterization of new models so that they can be integrated into the regulatory pipeline. There is a huge opportunity for these systems to supplement the data that are currently being generated in animals with more human-relevant data. This is particularly important for biologics and gene therapies where the modalities are incredibly human specific. We are looking for specific contexts of use for these tools where they have a significant value add/or demonstrated improvement over the current standard assay. We believe that’s where we should focus to qualify potential drug development tools. Q: What is the stance of regulatory bodies on the use of MPS in drug discovery? A: The FDA is willing to accept any data that the applicant wants to include in their submission, and, to date, some drugs have moved into clinical trials on the weight of evidence provided by MPS. A nice example is the Sanofi/Hesperos case, where the MPS data from their myelination chip were used to show efficacy and advance a therapeutic. The FDA has also formalized the Innovative Science and Technology Approaches for New Drugs (ISTAND) pathway for qualifying MPS models as drug development tools. There are a number of reasons why a developer might choose to qualify their model through this pathway, but I hope that the work that we are doing will make it easier for developers to create validation packages for models that are being included in submissions, and find appropriate contexts of use and drafting qualification plans if they want to move their model into the drug development tool pipeline. The impression that I get from talking to some colleagues in regulatory agencies is that they are excited by the possibility that these tools will improve patient safety, but we need to make sure they are properly characterized to ensure their appropriate use. These tools and solutions help de-risk decision making in the development and regulatory review process of novel medical products. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 15 Q: At SLAS 2025, your talk discussed a novel framework to support FDA qualification of CIVMs for use in regulatory submissions. Can you tell us about this framework, how it was developed and its current status of use? A: Our group, the Predictive Safety Testing Consortium (PSTC), was the recipient of a Broad Agency Announcement project contract from the FDA. The project contract was to fund work with the team in the Division of Applied Regulatory Science to perform a landscape analysis of the regulatory readiness of commercially available MPS models and to host a series of public workshops to bring together stakeholders from regulatory agencies, 3D tissue model developers, academics and pharmaceutical industry scientists. The goal of these public meetings has been to open lines of dialogue between the groups, identify areas of unmet regulatory need and highlight gaps in existing models where CIVMs would improve regulatory evaluation of drugs, whether that’s by improving the ability of the models to predict drug efficacy in a disease model or demonstrating drug safety for moving a new molecule into the clinic. We’ve taken the output from the first meeting and written a whitepaper on the pathway to use CIVM for regulatory applications. The output from the second workshop is being drafted as a manuscript and updated to the existing whitepaper document. Q: What role can automation and AI play in advancing the role of MPS in drug discovery and development? A: The benefit that automation can provide is increasing the reproducibility of MPS assays and thus increasing the confidence in the models. A key component of validating MPS models for regulatory assessment is building confidence that the data they produce is robust and reproducible. The tools being developed for laboratory automation and liquid handling can eliminate a key source of variability in these systems. Combining AI/ML models with MPS models has great potential to produce datasets with increased depth and predictivity, as the algorithms promise to find higher order trends in the data. Computer vision systems and automated analysis tools will enable faster and more thorough processing of large datasets to enable higher throughput screens and the generation of larger and more reproducible and relevant datasets. • Dr. Graham Marsh was speaking with Molly Coddington, Senior Writer and Newsroom Team Lead for Technology Networks. ABOUT THE INTERVIEWEES Dr. Graham Marsh is a scientific director in the Critical Path Institute's Predictive Safety Testing Consortium. He is working to enable the use of complex in vitro models for regulatory applications by establishing evidentiary considerations for their qualification as drug development tools. What is the ISTAND Pilot Program? ISTAND, which launched in 2020, is a program that supports the development of new DDTs to be used in regulatory applications for novel medical products. Examples of submissions that might be considered for ISTAND include the use of MPS, AI-based algorithms or the use of novel digital health technologies, such as wearables, for patient assessment. 16 DRUG DISCOVERY Though originally approved for treating type 2 diabetes, semaglutide (Ozempic™ and Wegovy™) and tirzepatide (Mounjaro™) have garnered increased attention over the last few years due to their weight loss effects. These drugs belong to a class known as glucagon-like peptide 1 receptor agonists (GLP-1RAs). This article will explore the benefits and risks of GLP-1ARs, discussing their future implications and potential alternatives. GLP-1RAs – successes in diabetes and beyond Before their use as a weight loss intervention, GLP1RAs were trialed and approved for their ability to reduce glucose levels effectively in type 2 diabetes. The first GLP-1RA to be approved by the US Food and Drug Administration (FDA), for type 2 diabetes, exenatide, required twice daily injections. In 2019, semaglutide became the first oral medication of this class to be approved by the FDA. This oral form (Rybelsus™) must be taken once daily. The injectable form (Ozempic and Wegovy) is administered once weekly. The Promise and Perils of Weight Loss Drugs Kate Robinson Credit: iStock How do GLP-1RAs work? Glucagon-like peptide 1 (GLP-1) is a hormone that triggers the release of insulin (lowering the amount of glucose in the blood), blocks the secretion of glucagon (which raises blood sugar levels), slows the emptying of the stomach and increases satiety. GLP-1 agonist drugs mimic this hormone. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 17 As the use of GLP-1RAs for diabetes management has increased, the discovery of their impact on weight loss has sparked interest in their potential for obesity treatment. A study published in the New England Journal of Medicine found that adults with obesity had a mean weight loss of 14.9% with semaglutide and lifestyle intervention. This exceeded the loss with placebo plus lifestyle intervention by 12.4 percentage points. Tirzepatide, a dual-acting GLP-1/glucose-dependent insulinotropic polypeptide (GIP) agonist, has shown greater glucose and weight lowering effects than semaglutide. The drug is also effective at reducing blood pressure, waist circumference, body weight and liver fat content. “GLP-1RAs have shown impressive clinical benefits in multiple trials. They can lead to an average weight loss of 15%–20%, improve cardiometabolic risk factors and prevent secondary cardiovascular events. They also slow the progression of kidney disease and reduce the severity of obesity-related conditions, like obstructive sleep apnea,” said Dr. David D. Kim, assistant professor of medicine and public health at the University of Chicago. GLP-1RAs could also provide benefits outside of diabetes and obesity management. A recent study, published in Nature Medicine, found an association between GLP1-RAs and benefits to neurological and behavioral health, with reduced risks of seizures and addiction to alcohol, cannabis, stimulants and opioids. Participants taking the drugs also experienced decreased risks of suicidal ideation, self-harm, bulimia and psychotic disorders such as schizophrenia. Further studies have shown potential benefits of GLP1RAs in fatty liver disease, chronic kidney disease and heart disease. Could GLP-1Ras exacerbate eating disorders? The success of GLP-1RAs has led to an increase in demand and supply shortages, leading to a rise in counterfeit versions of these products being sold. These products can contain any number of ingredients, potentially leading to unknown adverse events or accidental overdoses. Legitimate GLP-1RAs can cause nausea, vomiting, diarrhea, dizziness, mild heart rate increase, infections, headaches and indigestion. Rare side effects include pancreatitis, thyroid cancer, kidney injury and worsening diabetes-related retinopathy. One potential area for concern, according to Dr. Riccardo Dalle Grave, director of the Department of Eating and Weight Disorders at Villa Garda Hospital, Italy, is that these drugs could potentially contribute to the onset or exacerbation of eating disorder symptoms. “By enhancing feelings of satiety and suppressing hunger, GLP-1RAs may exacerbate dietary restriction (physiological undereating) and dietary restraint (the cognitive effort to limit food intake),” Dalle Grave said. “This can encourage the adoption of rigid and extreme eating patterns, such as skipping meals, consuming minimal portions or avoiding specific foods altogether. These behaviors are core characteristics and perpetuating factors of eating disorders. Moreover, common side effects of GLP-1RAs, such as nausea, vomiting and diarrhea, can further suppress appetite, reinforcing restrictive eating behaviors.” For those with existing eating disorders, Dalle Grave explained how “the appetite-suppressing effects of GLP1RAs may conflict with key eating disorder treatment approaches, which emphasize re-establishing regular eating habits and reducing restrictive behaviors”. Conversely, some researchers believe GLP-1RAs could be used to treat binge-eating disorder (BED), which is characterized by recurrent binge episodes without compensatory behaviors such as excessive exercise, inducing vomiting or using laxatives. “Although some evidence suggests they may reduce binge eating, GLP-1RAs are not approved for BED treatment. Their use should be limited to cases where binge episodes are substantially reduced, regular eating patterns are established and healthy lifestyle changes are adopted. Close monitoring is essential to detect worsening eating disorder symptoms, such as rigid dietary rules or meal skipping,” said Dalle Grave, “the TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 18 role of GLP-1RAs in obesity when it coexists with BED requires further research.” The full impact of weight loss drugs on other mental health conditions remains unclear. A Scientific Reports study found that liraglutide and semaglutide increased anxiety and suicidal ideations in females and younger participants in real-world settings. In one case, a patient with a history of depression experienced depressive symptoms after four weeks of treatment with semaglutide, which ceased when treatment stopped. Another study of the reported adverse events for semaglutide, liraglutide and tirzepatide over a period of 28 months found that while only 1.2% of the total reports were psychiatric adverse events, there were 9 deaths and 11 life-threatening outcomes due to suicide attempts in this time period. Depression, anxiety and suicidal ideation were also reported. The future of weight loss Weight loss medications haven’t been around long enough to have a full picture of their long-term effects. “While clinical trials and post-market studies have provided robust evidence of efficacy and safety over a few years, there is still limited data on the long-term effects of GLP-1RA use. This uncertainty is something we’ll need to continue monitoring as more people use these medications for extended periods,” said Kim. It remains to be seen if these drugs could have impacts on metabolism, mental health or other chronic conditions. “By reducing obesity-related complications, GLP-1RAs can lower long-term healthcare costs. However, at their current net price in the US, the long-term cost savings don’t fully offset the increased spending on these medications. So, while they offer tremendous health benefits, even with insurance coverage, patients often face substantial out-of-pocket expenses.” The high cost associated with these drugs is likely one of the factors leading over 50% of users to discontinue use before the one year mark. Over 84% of users without type 2 diabetes discontinued use before two years. According to Kim, the financial burden and potential side effects of long-term GLP-1RA use highlight the need for an alternative strategy. Studies have also shown that patients can gain weight after discontinuing GLP-1RAs. One study found a significant association between weight re-gain and reinitiation of treatment. According to Kim, “this occurs because GLP-1RAs not only help reduce appetite and improve metabolism while they're active, but they also influence hormonal pathways that regulate hunger and satiety. Once the medication is stopped, these pathways often revert to their pre-treatment state, making it harder for patients to sustain their progress without additional support.” A paper co-authored by Kim in 2024 suggested that, while potentially less effective than weight loss drugs, weight-maintenance strategies could optimize the clinical benefits of reducing unhealthy weight more efficiently and equitably. “Weight-maintenance programs, which emphasize lifestyle modifications like diet, exercise and behavioral counseling – often following an initial weight loss phase achieved with GLP-1RAs – offer a more sustainable and affordable alternative to long-term medication use. These programs avoid the high recurring costs associated with GLP-1RAs and eliminate the risks of medication-related side effects,” Kim said. “This approach is particularly important for disadvantaged populations, who are disproportionately affected by obesity and its complications, and who stand to benefit the most from equitable access to these interventions.” One month supply list prices Ozempic 1 mg (semaglutide): 936 USD Wegovy 2.4 mg (semaglutide): 1,349 USD Rybelsus 7 mg (semaglutide): 936 USD Mounjaro 15 mg (tirzepatide): 1,023 USD TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 19 GLP-1RAs offer transformative health benefits to many patients. However, these medications are not without risks. It will be critical to address gaps in our understanding of their long-term effects and to explore how these medications can be integrated into broader, more sustainable weight management strategies. The future of weight loss treatments lies not only in advancing pharmacological options but also in ensuring these solutions are accessible, affordable and part of a comprehensive strategy tailored to the diverse needs of patients worldwide. • ABOUT THE INTERVIEWEES David D. Kim, PhD is an assistant professor of Medicine and Public Health Sciences at the University of Chicago. As a health economist, Dr. Kim's primary focus centers around measuring the value of health interventions and providing guidance for valuebased health care decisions. Riccardo Dalle Grave, MD is the director of the Department of Eating and Weight Disorders at Villa Garda Hospital (Garda, VR, Italy). Currently, the focus of his research is evaluating the cognitive behavior therapy of adult and adolescent patients with eating disorders and obesity, respectively, both in outpatient and inpatient settings. Choose Lonza for Optimal Cell Performance Lonza’s primary cells and media are globally renowned for quality and reliability. With over 40 years of experience and referenced in 10 times more publications than other suppliers, Lonza can deliver the quality you need to obtain reliable, and biologically relevant reults every time. Our comprehensive cell type offering is unmatched and spans across research areas such as respiratory, neurobiology, cancer, stem cells, cardiovascular, toxicology, and others. Primary Cells and Media Portfolio: • 100+ cell types – cryopreserved, human and animal • Broad donor variety – large selection of donors for most cell types • Cells from normal and diseased tissues • Optimized Growth Media BulletKit® for each cell type Your Trusted Source for Primary Cells lonza.com/primary-cells All trademarks belong to Lonza, and are registered in the USA, EU and/or CH or belong to third-party owners and are used only for informational purposes. However, no warranty is made, either expressed or implied. For more details: http://www.lonza.com/legal. © 2025 Lonza. All rights reserved. CD-AD154 03/25 Harvest 40 Years of Primary Cell Expertise Enabling a Healthier World Learn more. 21 DRUG DISCOVERY Antibodies have become an integral part of research and medicine. Therapeutic applications of antibodies began to emerge following the publication of Köhler and Milstein’s groundbreaking 1975 paper in Nature describing the hybridoma technique to produce monoclonal antibodies (mAbs). Introducing mAb technology enabled researchers to produce a single antibody to a specific antigen and replicate it in culture. In 1986, the Food and Drug Administration (FDA) approved the first therapeutic mAb designed to prevent transplant rejection. Since then, more than 100 mAbs have been approved for treating a range of diseases including cancer, autoimmune and chronic inflammatory diseases. mAbs synthesized in the laboratory mimic natural antibodies produced by the body and are designed to target and neutralize pathogenic proteins or antigens selectively. A specific class of mAb, capable of broad neutralization, has become highly valued in vaccine development for its ability to neutralize multiple virus strains. Broadly neutralizing antibodies (bNAbs) were first discovered in the '90s when it was observed that HIVinfected individuals possessed antibodies that could recognize and neutralize different subtypes of HIV. bNAbs are now being heavily researched, not only for their potential in the prevention of HIV, but also for other rapidly mutating viruses such as influenza and SARS-CoV-2. How Broadly Neutralizing Antibodies Are Driving Next-Gen Vaccines Blake Forman Credit: Technology Networks TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 22 Developing vaccines against an evolving threat During replication, the nucleic acid of many viruses will mutate, reducing the protective ability of vaccines. Combating the ability of mutated viruses to escape the immune system remains one of the most pressing challenges faced by vaccine developers. “Viruses are constantly under selective pressure from the human immune response,” Dr. William Voss, a postdoctoral fellow at The University of Texas at Austin told Technology Networks. “A particular virion that is neutralized by an antibody during infection cannot enter its host cell and replicate. This drives the process of immune escape, where viral variants that mutate the epitope targeted by a given neutralizing antibody, such that it no longer binds or neutralizes, survive and pass on their genetic material.” The development of broad-spectrum vaccines that can induce bNAbs against various virus strains has been identified as one of the most promising ways to combat these mutations. “When it comes to bNAbs potential in vaccines, two approaches are the subject of investigation. The first involves the concept of passively transferring vaccine-like antibodies into an individual. This would only be possible if you can extend the half-life of said antibodies,” Dr. Michael Diamond, the Herbert S. Gasser Professor in the department of medicine, molecular microbiology, pathology and immunology at Washington University School of Medicine told Technology Networks. “This approach was taken by AstraZeneca when it produced Evusheld® (tixagevimab/cilgavimab), a long half-life mAb combination that could be administered prophylactically to combat emerging waves of SARS-CoV-2. The problem with Evusheld, and most other therapeutic anti-SARS-CoV-2 mAbs, was that it lost its effectiveness against newer variants and resistance emerged.” Another concept is to induce bNAbs by providing a tailored antigen designed to focus the immune response on conserved epitopes of a virus. “There are vaccines that are trying to do this, and although they've been able to generate broadly neutralizing responses there hasn’t been much success generating bNAbs consistently,” explained Diamond. Unraveling the mechanism of these antibody “heroes” Like most antibodies, bNAbs are Y-shaped proteins (Figure 1) generated by a type of white blood cell called B What are conserved epitopes? Conserved epitopes are portions of a foreign protein or antigen retained by multiple strains of a virus that binds with a complementary site of an antibody – such as the S2 domain of SARS-CoV-2. FIGURE 1: Structure of an antibody. Credit: Technology Networks TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 23 cells. The exact mechanism of action of bNAbs has been an ongoing area of investigation. However, research has shown that most bNAbs target conserved epitopes. In 2022, researchers from The Pasteur Institute’s Virus and Immunity Unit described how anti-HIV bNAbs bind to viral particles to form aggregates at the surface of immune cells. These aggregates effectively block cellto-cell transmission by preventing the release of viral particles and the formation of synapses used by viruses to move from one cell to another. Producing bNAbs naturally in the human body is a long process in an antibody–virus race for dominance. For example, potent bNAbs develop in people living with HIV, but only rarely and after many months or even years after transmission. “Dr. Dennis Burton's group and others have shown that you require a substantial amount of somatic hypermutation over the context of many exposures to evolve these bNAbs. Work from Dr. Michel Nussenzweig has also shown this elegantly at the single B-cell level,” said Diamond. As you could expect, identifying and characterizing bNAbs is no easy task; scientists have to comb through thousands of antibodies to identify those likely to be active against most viral strains. Typical approaches for the high-throughput screening of antibodies include phage display, whereby highaffinity interactions between antibodies and antigens are identified by displaying proteins on the surface of bacteriophages. Techniques such as enzyme-linked immunosorbent assays (ELISAs) are often employed in hybridoma screening to identify monoclonal antibodies with high antigen affinity. Diamond explained how antibody screening can also be done at a single B-cell level: “You can identify specific B cells that interact with a viral protein, and then make the antibody that single B cell encodes. Now you have a single antibody from a single B cell that binds to your protein of interest. Depending upon the sophistication of your screen, you may even be able to know right away if that's a neutralizing anybody.” More recently, artificial intelligence (AI) and machine learning approaches have been suggested. AI could be useful for screening methods such as epitope/paratope mapping to predict the areas of the antibody (the paratope) and antigen (the epitope) involved in binding. However, AI methods can lack accuracy and still require experimental input. In the context of mutating viruses, researchers have used machine learning to computationally redesign an existing antibody against an emerging strain of SARSCoV-2 while maintaining efficacy against the dominant variant. The study's findings suggest that computational approaches can be used to optimize an antibody to target multiple escape variants. Identifying bNAbs and utilizing them in vaccine technology has proven challenging, however, researchers have made multiple strides this year alone in disease areas such as COVID-19 and HIV. Towards a preventative HIV vaccine Today, infection with HIV is manageable using antiretroviral medications, however, a successful vaccine has alluded developers since the ‘80s. A critical roadblock in developing a preventative vaccine has been the inability to induce B-cell lineages of bNAbs that target the rapidly evolving virus. A vaccine candidate developed at the Duke Human Vaccine Institute has now reportedly triggered low levels of HIV bNAbs among a small group of people in a clinical trial. The vaccine targets an area on the HIV-1 outer envelope called the membrane-proximal external region (MPER), which remains stable even as the virus mutates. In the study, the researchers analyzed data from the HVTN 133 Phase 1 clinical trial, which involved 20 healthy, HIVnegative individuals. “One of the questions we have worried about for many years is if it will take years to induce bNAbs with a TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 24 vaccine like it takes for bNAbs to develop in people living with HIV,” Dr. Barton Haynes, director of the Duke Human Vaccine Institute previously told Technology Networks. “Here we found that bNAb lineages developed after the second immunization.” This work shows the feasibility of inducing antibodies that neutralize the most difficult strains of HIV, however, the researchers stress that there is still more work to be done to create a more robust response. A separate study, conducted by the Scripps Consortium for HIV/AIDS Vaccine Development, utilized germline targeting to stimulate animals’ immune systems to induce rare precursor B cells of a class of HIV-targeting bNAbs called 10E8. The 10E8 bNAb binds to a conserved region of the glycoprotein gp41 on HIV’s surface. Designing an immunogen to stimulate the production of 10E8 bNAbs has been challenging because the binding region of gp41 is hidden in a recessed crevice on the virus’ surface. To address this challenge, the researchers engineered immunogens on nanoparticles that mimic a specific part of gp41. Vaccinations in rhesus macaque monkeys and mice with these immunogens elicited responses from the 10E8 B cell precursors, and induced antibodies that showed signs of maturing into bNAbs that could reach the gp41 region. The research forms part of the group's larger work to develop a germline-targeting strategy for priming the immune system to elicit a bNAb called VRC01, which was discovered by NIAID researchers almost 15 years ago. bNAbs presence in COVID-19 research The first vaccine a person receives promotes a strong primary immune response that shapes future interactions with the virus, a process known as imprinting. Diamond and colleagues at Washington University School of Medicine in St. Louis recently detailed how imprinting affects subsequent COVID-19 vaccinations. Unlike the influenza virus, where immunity elicited by one year’s flu shot can interfere with subsequent immune responses, the researchers found that repeat vaccinations resulted in the production of bNAbs capable of neutralizing a wide range of SARS-CoV-2 variants. The researchers concluded that these cross-reactive antibodies may confer substantial protection against future pandemics caused by a related coronavirus. One bNAb to neutralize all variants Researchers at The University of Texas at Austin recently discovered and isolated a particular bNAb, called SC27, which appears effective at neutralizing the numerous variants of SARS-CoV-2. “This research – including understanding how SC27 achieves its broadly neutralizing activity – helps inform vaccine development,” explained Voss. “Future vaccines that can trigger the production of such antibodies could protect us more broadly against emerging viral variants as SARS-CoV-2 continues to evolve. Additionally, SC27 itself could potentially be used as a therapeutic antibody.” SC27 recognized the different characteristics of the spike proteins in the many COVID variants. “A technique called deep mutational scanning quantified the potential “Antibodies such as SC27 that may retain neutralizing activity despite future viral evolution represent a promising area of drug development,” said Voss. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 25 for an array of spike mutations to escape SC27 and demonstrated that such mutations are rarely observed in circulating SARS-CoV-2,” described Voss. “Several key amino acid residues within the epitope targeted by SC27 show minimal natural variation across SARS-CoV-2 variants, suggesting that SC27 may remain potently neutralizing moving forward.” To isolate and identify the antibody the researchers developed a novel technique combining single-B cell sequencing and immunoglobulin proteomics, a method they named Ig-Seq. Beyond COVID-19 research, Voss believes this approach could be used to study other rapidly mutating viruses: “As a high-throughput method for characterizing the plasma antibody repertoire and facilitating the cloning and characterization of specific antibodies of interest, Ig-Seq could be used to identify broadly neutralizing epitopes on a variety of pathogens, including influenza.” Voss continued, “Identifying such regions of viral proteins and understanding the mechanism of antibodies that target them could inform the development of vaccines that aim to elicit bNAbs.” How close are we to “one shot” vaccines? Advancements in structural biology and immunologic technologies have brought researchers closer than ever to understanding bNAbs and the mechanisms that drive their production. “To get a single shot vaccine to prevent infection in a sustained way, we also need to accelerate the development of mucosal vaccines. The emerging consensus is that most vaccines administered by an intramuscular route don’t induce enough upper airway immunity, especially in the setting of evolving variants that compromise neutralizing activity,” Diamond said of the possibility of a “one shot” vaccine for respiratory viruses. Diamond envisions two approaches could translate bNAbs to the clinic in the next few years. The first involves the concept of vaccine-like antibodies with an extended half-life. Instead of vaccinating and inducing an immune response, this would involve giving a patient a bNAb. “The advantage of this approach is that elderly and immune-compromised people wouldn’t have to rely on a dysfunctional immune system making an antibody,” explained Diamond. “The downside is that you run the risk that if a virus is highly evolving you could generate escape in a population relatively quickly, as was the case with Evushield.” The second approach would involve using vaccines to induce the production of bNAbs in a patient. “Work still needs to be done to improve our understanding of how to focus and display epitopes recognized by bNAbs to be able to induce antibodies specifically and with high precision. We are still struggling as a field in the best way to do that. The rules that may work for flu may not be the same for HIV because the epitopes are different and must be displayed differently. “Alongside targeting specific epitopes with bNAbs, a successful ‘one shot’ vaccine will also need to induce ancillary immune responses such as T-cell responses and Fc effector responses,” said Diamond. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 26 Unfortunately, the lessons we continue to learn from one virus might not translate across different viruses,” Diamond concluded. • ABOUT THE INTERVIEWEES Dr. Michael Diamond is the Herbert S. Gasser Professor in the Department of Medicine, Molecular Microbiology, Pathology and Immunology at Washington University School of Medicine. He earned his PhD in cell and developmental biology from Harvard University and an MD from Harvard Medical School. His research group studies the molecular basis of disease of globally emerging RNA viruses, focusing on the interface between pathogenesis and host immunity. Dr. William Voss is a postdoctoral fellow at The University of Texas at Austin. He earned his PhD in cell and molecular biology from The University of Texas at Austin during which he was awarded the Outstanding Research Paper Award, Department of Molecular Biosciences, The University of Texas at Austin, April 2022 for the 2021 publication in Science titled “Prevalent, protective, and convergent IgG recognition of SARS-CoV-2 non-RBD spike epitopes”. 27 DRUG DISCOVERY Gain More Insights. Make Better Decisions. Sartorius accelerates the development of breakthrough therapeutics with innovative solutions for lab filtration, cell/protein analysis, and more. Ensure confidence in your biotherapeutic discovery and development program through: • Process streamlining • Multiplexing • Information-rich data • Biologically relevant insights www.sartorius.com/biologics 29 DRUG DISCOVERY Impurities in pharmaceuticals are a major concern for drug manufacturers, as they can significantly impact the quality, safety and effectiveness of the final product. Even a single unknown impurity discovered late in production can lead to the rejection of entire batches. The International Council for Harmonisation (ICH) defines an impurity as any substance in a drug product that is not the active pharmaceutical ingredient or the excipients. Impurities are categorized into organic impurities, inorganic impurities, other materials and residual solvents. They can originate at various stages – from manufacturing to transportation and storage. During production, impurities may arise from interactions between the active pharmaceutical ingredient (API) and excipients, or from contact with packaging materials. Understanding these sources is crucial for maintaining the purity and safety of pharmaceuticals throughout their lifecycle. Impact of impurities on product approvals and regulatory actions The presence of impurities can delay product approvals during manufacturing and prompt recalls once products are on the market, triggering regulatory actions. Recent incidents involving substances like N-nitrosodimethylamine (NDMA) in medications such as ranitidine and valsartan have resulted in widespread recalls, highlighting the ongoing challenges in effectively managing pharmaceutical impurities. Navigating the Complexities of Impurities in Pharmaceuticals Neeta Ratanghayra, MPharm Credit: iStock TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 30 Naiffer Romero, USP Principal Scientist and Community Manager of the Nitrosamines Exchange says, “Since nitrosamines were first found in drug products in 2018, there has been a coordinated effort among international regulatory and health agencies to advance the development of guidance to mitigate their presence, collaboration with industry and manufacturers to deepen the science and understanding of identifying and testing these impurities in medicines. Although our understanding of the issue has come a long way, it continues to evolve as new challenges arise, and the problem facing industry is far from over. Regulatory agencies initially aimed to unify their approach to nitrosamines in pharmaceuticals, but global variation in testing capabilities has led to differing stages of managing and reducing these impurities. This highlights the importance of discussions and educational efforts among regulators, drug manufacturers and industry stakeholders to address the issue.” ICH guidelines for managing impurities in drug substances and products The quantification, qualification, identification and control of impurities are critical in drug development to ensure the safety and purity of the final drug product. International and regional guidelines play a key role in guiding drug developers and regulatory agencies in evaluating and managing impurities in both drug substances and products. The ICH has established several key guidelines for managing impurities. The ICH Q3A focuses on impurities in new drug substances, while ICH Q3B addresses impurities in new drug products. These guidelines outline essential criteria including identification and characterization, accurate quantification, established limits and understanding the origin of impurities. They also emphasize the importance of conducting toxicological assessments, evaluating the stability of the drug in the presence of impurities, ensuring regulatory compliance, performing thorough risk assessments and implementing effective control strategies. While reducing impurities to practical minimums is ideal, complete elimination is often not feasible, necessitating the establishment of specific impurity criteria. The ICH Q3A and Q3B guidelines provide essential thresholds for reporting, identifying and qualifying impurities in new drug substances and new drug products respectively. Impurity investigations by phase of development Managing impurities is crucial throughout the entire product lifecycle, from initial development to manufacturing and distribution. Yaman Abdin, research fellow at Saarland University, says, “Impurities are everywhere! This simple truth keeps colleagues in quality control, from devising guidelines to implementing strategies, very busy. Impurities are an inevitable challenge in chemistry, especially in pharmacy, and the field is dynamic and evolving.” The level of scrutiny in impurity investigations depends on the project's development phase. In the early stages of development, it's impractical to investigate all impurities; the focus should be on the most likely potential impurities observed in the initial phases (e.g., intermediates, solvents, predictable by-products from stress studies). In the later phases of development, more detailed studies are conducted to understand impurity origins and behaviors, guiding decisions on which impurities require routine monitoring with defined limits. Stress degradation studies in later phases further identify degradation products, helping to inform formulation and storage requirements. “We're constrained by the accuracy and precision of our analytical methods as well as the fact that we only find what we look for. To manage impurities effectively, we must focus on the purity of starting materials, controlled processing environments, and proper handling and storage. Adopting a “quality by design” approach is key to achieving better purity profiles,” explains Abdin. Analytical techniques for impurity detection A variety of analytical techniques are employed to identify and quantify impurities throughout the drug development process. Each method offers distinct advantages and is suited to specific types of analyses. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 31 Below, we explore several key analytical methods used for impurity detection in pharmaceutical products. Advances in NMR‐based characterization of drug impurities NMR facilitates the identification and confirmation of molecular structures, aiding in the detection of impurities. NMR helps elucidate the mechanisms behind the formation of process and degradation impurities, which is vital for maintaining drug quality. However, challenges remain. Gary Martin, adjunct professor at the Stevens Institute of Technology, explains, “Undoubtedly, the biggest challenge associated with the identification and characterization of drug impurities is the size of the sample that can be isolated vs. the NMR probe technology available where the research is being done. While sensitivity has never been an issue for mass spectrometric methods, quite the opposite is true for NMR spectroscopy, which is notoriously sensitivitychallenged. Obviously, higher-field NMR spectrometers are advantageous.” Highlighting the recent advances, Martin says “Probably one of the most significant recently developed techniques that can be used in the characterization of drug impurities was the development of the i-HMBC experiment, which allows the unequivocal differentiation of two-bond from three-bond long-range or longer-range correlations. The full potential of this experiment and the range of applications has only just begun to be realized.” Method Description Thin layer chromatography Cost-effective method for separating drug components and identifying impurities; minimal sample preparation and high sample loading capacity. High-performance liquid chromatography Offers excellent specificity and precision; often combined with mass spectrometry (LC-MS) for impurity analysis. Requires extensive system suitability testing. Gas chromatography Effective for analyzing volatile organic compounds; derivatization expands its application to nonvolatile substances. Used to analyze residual solvents and process-related impurities. Near-infrared spectroscopy Rapid, non-destructive method suitable for multi-component analysis with minimal sample preparation. Ability to extract multiple parameters from a single spectrum. Nuclear magnetic resonance (NMR) spectroscopy A valuable tool for identifying and confirming molecular structures, thus helping detect impurities. It also helps in decoding the mechanisms behind their formation and degradation. Electrochemical methods Gained popularity for drug analysis due to advanced instrumentation and improved understanding; includes methods like cyclic voltammetry and adsorptive stripping voltammetry. Kinetic methods Focuses on measuring concentration changes over time; applicable techniques include fixed-time and initial rate methods. Electrophoretic methods Capillary electrophoresis offers effective separation of charged analytes; efficient and requires minimal sample volume. Flow injection and sequential injection analysis Flow injection analysis (FIA) automates chemical procedures by injecting samples into a continuous liquid stream, allowing real-time measurement. Sequential injection analysis builds on FIA principles with programmable flow, enhancing automation in pharmaceutical analysis. Both methods improve sampling rates. Hyphenated techniques Combine separation methods with online detection. Includes LC-MS, GC-MS (gas chromatography-mass spectrometry), CE-ICP-MS (capillary electrophoresis-inductively coupled plasma mass spectrometry) and CE-MS (capillary electrophoresis-mass spectrometry). TABLE 1: Analytical methods used for the detection of impurities in drug products. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 32 Strategies for minimizing drug impurities To minimize drug impurities, several effective strategies can be implemented. Firstly, optimizing synthesis routes and process controls ensures efficient pathways, significantly reducing impurity formation. Additionally, using high-quality starting materials with low impurity profiles helps to limit contaminants in the final product. Strict adherence to good manufacturing practices (GMP) is essential for maintaining high production standards and minimizing impurities. Controlled storage and handling conditions, including proper temperature and humidity management, prevent degradation and the formation of impurities. Lastly, thorough validation of cleaning procedures ensures that equipment and facilities are free from cross-contamination, further safeguarding product integrity. “In addition to the general requirements manufacturers must meet to analyze their products for impurities, to identify those that may arise during manufacturing, and to conduct stability studies – when it comes to nitrosamines specifically – there is a need for more preemptive actions to effectively head off the risks,” Romero explains. As per Romero, pharmaceutical companies can take the following proactive actions to mitigate the risks: • Develop and implement risk-based assessments to evaluate chemical structures, manufacturing processes, raw materials and historical data to help determine which products are more vulnerable to the formation of nitrosamines. • Adopt a culture of continuous improvement, regularly reviewing and refining their risk management strategies, manufacturing processes and testing protocols. • Proactively test medicines for impurities throughout a product’s life cycle for better detection, assessment and action to keep the global medicines supply chain safe. Regardless of the source of the impurities – whether from manufacturing to transportation or storage – comprehensive risk assessment and mitigation ultimately helps determine the safety of a product in the hands of a patient, adds Romero. Promoting collaboration and innovation in addressing drug impurities By adopting innovative strategies and fostering partnerships across the industry, stakeholders can effectively address the emerging issues of drug impurities and prevent unforeseen product recalls. Romero says, “Information and knowledge sharing allows for open discussions regarding recent findings and updated regulatory requirements. To facilitate collaboration and information sharing among the global network of professionals concerned with the issue, USP created the Nitrosamines Exchange, a dedicated knowledge-based community designed to allow industry subject matter experts, along with representatives from international regulatory and health agencies, to discuss recent updates and engage in active problem-solving. Members of the quickly growing community of 4,000+ share information and solutions to mitigate nitrosamines through thread conversations, questions and anecdotal experiences. By participating in these types of conversations, industry can help prevent future nitrosamine-related recalls and help ensure medicines remain safe for patients.” Abdin adds, “Global harmonization of regulatory standards and constantly improving analytical techniques have significantly enhanced our ability to detect and control impurities. However, emerging challenges such as microplastic and nanoplastic impurities could find their way or maybe already found their way to drug products and hence represent the next frontier. Addressing these new types of contaminants will require innovative methods and continued global collaboration to ensure the safety and efficacy of pharmaceuticals.” • ABOUT THE INTERVIEWEES Gary Martin is an American chemist and expert in NMR spectroscopy and medicinal chemistry. Formerly with the Structure Elucidation Group at Merck, he is now an adjunct professor of Chemistry at both Seton Hall University and Stevens Institute of Technology. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 33 His research focuses on developing new NMR methods for characterizing the molecular structure of pharmaceutical impurities, degradants, drug metabolites and natural products. Martin has written a widely used monograph on 2D NMR methods and coedited two volumes on modern NMR applications in natural product structure elucidation. He has published over 325 papers, more than 45 invited reviews and chapters, and delivered over 500 seminars and lectures at national and international meetings. Naiffer Romero is a Principal Scientist at the U.S. Pharmacopeia (USP), where he leads scientific outreach and technical engagement on national health priorities in Latin America and the United States. With more than 20 years of experience in the pharmaceutical industry and an expert in nitrosamine impurities, he manages USP’s Nitrosamines Exchange online community and serves as USP representative on several international nitrosamines workstream committees. Yaman Abdin is a postdoctoral researcher at the Institute for Bioorganic Chemistry, School of Pharmacy, Saarland University, Germany. His research focuses on the philosophical, social and psychological aspects of pharmacy, encompassing drug development, regulation and application. He leads the 'Pharmasophy' group at the Institute for Bioorganic Chemistry. Reserve Your Place for Early Access Be among the first to secure your spot at our exclusive online event on drug discovery and development! Gain early access to cutting-edge discussions on small molecule and biologic drug development, high-throughput screening and novel target identification strategies. REGISTER NOW Brought to you by the publication September 24-25, 2025 8AM PDT | 11AM EDT | 4PM GMT Advances in Drug Discovery & Development 2025 ONLINE SYMPOSIUM TECHNOLOGY SPOTLIGHT SPONSORS STANDARD SPONSORS PLATINUM SPONSOR • Be one of the first to gain access to scientific discussions • Receive exclusive updates directly from our event platform • Get event insights as content is ready • Stay informed as talks and speakers are confirmed • Enjoy priority Q&A: Submit your questions early and they will be presented during the online event on a first-come, first-served basis Benefits of Early Access 35 DRUG DISCOVERY In recent years, we have seen significant advances in the development of drugs to tackle Alzheimer’s, particularly in the wake of two decades of largely unfruitful research. Though some such treatments are being hailed as a success, not all researchers remain convinced. Regulators around the world have had differing receptions to the drugs, but despite their problems, research now seems to be trending in a positive direction. Emerging new treatments The past two years has seen regulators approve new drugs lecanemab and donanemab to treat Alzheimer’s disease, though their development hasn’t been plain sailing. Both are designed to target a protein called amyloid-beta in the brain that forms abnormal clumps called plaques. These plaques are thought to be the root cause of the disease as part of the “amyloid hypothesis”, though this idea has also been disputed by some. The first amyloid-targeting antibody to gain approval from the US Food and Drug Administration (FDA) – aducanumab – was given the green light in 2021. But it was not without controversy; three FDA advisors, whose committee had advised against aducanumab’s approval due to a lack of evidence of efficacy, resigned shortly after the decision. Aducanumab’s drugmaker, Biogen, later discontinued the drug in January 2024 to focus on the development of their new offering, lecanemab. The Evolving Treatment Landscape for Alzheimer’s Sarah Whelan, PhD Credit: iStock TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 36 Data from clinical trials suggest that amyloid-targeting drugs like lecanemab and donanemab provide modest benefits for slowing the disease’s progression, mostly during the early stages of the disease. Despite their costs – both risk-wise and financially – their approval heralds some hope for those affected by Alzheimer’s, and it is a positive step after years of trials finding that previous drug candidates failed to impress. There are several reasons why finding effective drugs to combat Alzheimer’s has been so difficult, as Andrew Doig, a professor of biochemistry at the University of Manchester, told Technology Networks: “Firstly, the target that has received most attention, amyloid-beta, is not at all easy to hit.” Doig explained that amyloid-beta likely exists in the brain in the form of multiple units stuck together in structures called oligomers. Each different oligomer can vary in toxicity and structure, making finding drugs that effectively bind to them a much more difficult task. “Even if we do have good structures of oligomers, it isn’t clear which would be the most important (i.e., the most toxic). It is also unlikely that a drug would bind to all the toxic forms,” he said. The complex pathologies in the brain and the mechanisms at play that underpin Alzheimer’s development also make it challenging to target, as the disease’s characteristic brain abnormalities can emerge decades before any apparent symptoms. “By the time it is diagnosed, it could be too late to treat, as the brain has already undergone significant irreversible damage,” Doig said. To increase the chances of success, patients in the earlier stages of dementia – such as mild cognitive impairment – are now beginning to take center stage for clinical trials. Amyloid-beta’s other knock-on effects could also indicate that early treatment may be best, Doig explained, as the accumulated amyloid-beta likely kickstarts feedback loops in the brain involving oxidative stress, inflammation and tau – another key protein implicated in Alzheimer’s development. “Once these loops are triggered, removing toxic forms of amyloid-beta may have little effect,” he explained. Drawbacks for newly approved therapies Nonetheless, somewhat encouraging data from clinical trials have provided support for the approval of amyloidtargeting antibodies, suggesting they could have modest benefits for slowing down the disease’s progression. Lecanemab, for example, slows the progression of the disease in its earlier stages, rather than halting or reversing it. “All it does is to slow down the rate at which the disease progresses, as measured by cognitive ability,” Doig explained. “In effect, patients who take lecanemab see a delay in progression to more severe dementia by about six months.” These antibodies are delivered into a vein with the aim of binding to and clearing the brain’s amyloid-beta plaques; but not all are convinced as to whether this necessarily translates into meaningful benefits for the patients taking it. “The benefits of lecanemab are so modest as to be undetectable in an individual treated patient,” said Robert Howard, professor of old age psychiatry at University College London. “Although 27% slowing of disease course sounds impressive, this is not strictly what the analysis of the trial data showed.” Another drawback to these treatments is finding patients who are eligible to receive the drug. This requires undergoing expensive or invasive procedures such as PET scans and lumbar punctures, notwithstanding the eyewatering costs of the drug alone, which the manufacturers have set in the region of $26,500 a year. “The benefits are small, however, and there are concerns with the drug,” Doig adds, as, even after considering the costs, the drug carries the risk of potentially severe side effects. “There is a small but real risk that lecanemab can cause brain hemorrhage. A few patients on the trial died in this way,” Doig said, referring to amyloid-related imaging abnormalities (ARIA), which cause potentially fatal microbleeds or clots in the brain. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 37 Weighing the risks versus the benefits is therefore a difficult task. The patients likely to benefit most from the drug are those in the earliest stages of the disease, who, coincidentally, have the most to lose considering the risks. Weighing the benefits and risks This decision on whether to approve these drugs has proved arduous for many regulators worldwide, with some taking more conservative stances than others. The FDA was the first to give the green light in July 2023, while the European Medicines Agency (EMA) later decided against its approval in July 2024. The UK was next to follow in the FDA’s footsteps to approve lecanemab. However, they ruled against making it available on the National Health Service, reasoning that the small benefits do not justify the cost – meaning only those able to afford private healthcare can receive it. Another anti-amyloid antibody, donanemab, which also modestly slows cognitive decline at the risk of ARIA, earned FDA approval in July 2024. “The benefits are marginal, the costs are high and there is some risk with these drugs, so it is not surprising that many regulatory bodies are saying no,” Doig summarized. “I can understand why some do approve them, however, as we desperately need new therapies for Alzheimer’s, even if they are not especially effective.” Though further research could provide safer and more effective drug candidates, the approval of these first few drugs may be the starting point to show that we are on the right track. “Patients and carers can take heart that it is possible to slow cognitive decline caused by Alzheimer’s and that amyloid-beta is indeed an appropriate [drug] target,” Doig said. “It therefore points the way to a future where Alzheimer’s can be treated, bringing benefit to millions of people.” Potential for other treatment avenues Aside from amyloid-targeting antibodies, there are also other avenues that may be worth pursuing to add more tools to combat the disease. Doig described these in some of his predictions for the future of research into Alzheimer’s treatments over the coming decade: “We will bring forward a wider range of targets, rather than solely trying to clear amyloid-beta. Tau is next, but anti-inflammatories and antivirals also show promise. Many other pathways are affected by Alzheimer’s and might be useful drug targets.” Drug repurposing, like that of anti-inflammatories and antivirals, is one such approach that could be used to identify useful drug targets. Repurposing is the process of finding new applications for existing drugs: a significantly cheaper and potentially faster method to find new and effective treatments for many diseases. “Some therapies aimed at other conditions are showing real benefit for Alzheimer’s. These are the shingles vaccine, Shingrix®, and the anti-obesity drugs, such as semaglutide,” said Doig. The shingles vaccine targets a protein called HSV-1 that causes both chicken pox and shingles. Doig’s “Patients and carers can take heart that it is possible to slow cognitive decline caused by Alzheimer’s and that amyloid-beta is indeed an appropriate [drug] target,” Doig said. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 38 colleague, Ruth Izhaki, pioneered the investigation into the link between Alzheimer’s and HSV-1 for decades. However, her work has only recently gained wider acceptance. “The Shingrix vaccine seems to be roughly as effective as lecanemab at a much lower cost, without fortnightly administration and the worrying side effects,” Doig said. Meanwhile, tackling other conditions closely associated with Alzheimer’s could be another promising option to limit the disease’s incidence and progression: “We know that cardiovascular problems in middle age increase the risk of Alzheimer’s later on,” Doig said. “Tackling type 2 diabetes via suppressing appetite shows many benefits, including lowering the risk of Alzheimer’s. These are very exciting recent discoveries which offer cheap and effective ways to reduce Alzheimer’s.” The first step? Though the effort to find treatments for Alzheimer’s has not been straightforward, the emergence of these new drugs represents what is hopefully the first step on the journey to safer and more effective treatments. With diagnoses for people aged 65 and over projected to grow to 12.7 million by 2050, the pressing need for breakthroughs to prevent or cure the disease is important now more than ever. • ABOUT THE INTERVIEWEES Andrew Doig is a professor of biochemistry at the University of Manchester. He holds an MA in natural science and PhD in chemistry from the University of Cambridge, and carried out postdoctoral work at Stanford University. 39 DRUG DISCOVERY It is estimated by the World Health Organization (WHO) that by the end of 2022, 39 million people were living with human immunodeficiency virus (HIV), and in that year alone, 630,000 people had died from HIV-related causes and 1.3 million people had acquired the disease. With the assistance of 11 UN cosponsors, UNAIDS is hoping to end the HIV and AIDS epidemic by 2030. This article will explore the difficulties faced in attempting to treat HIV, an innovative prevention strategy and the possibility of a cure. Challenges in HIV management HIV is a retrovirus and can integrate its genetic material into host genomes, making it difficult to treat, and currently lacking a cure. If left untreated, HIV can lead to acquired immunodeficiency syndrome (AIDS). Unveiling the Progress and Challenges in the Fight Against HIV Kate Robinson Credit: iStock What is AIDS? AIDS is a disease that occurs when the immune system is damaged by HIV. When treated, HIV is prevented from progressing, so many people with HIV do not develop AIDS. A person with HIV is considered to have AIDS either when the number of CD4 (a type of white blood cell) cells drops below 200 cells per cubic millimeter (A healthy person has anywhere from 500 to 1,600 cells per cubic millimeter) or if they develop one or more opportunistic infections. Without treatment, people with AIDS typically survive around 3 years. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 40 Even though treatment can help to effectively manage the condition, some immune cells go into a dormant state but still contain viral DNA and can reemerge once treatment ceases. “HIV can establish latent reservoirs within our body. What this means is that they can hide within cells in our body and lay dormant for a long period of time (e.g., months or years). Once they become active, they can immediately replicate and infect other immune cells,” said Dr. Emmanuel Ho, a professor at the University of Waterloo. “HIV is able to alter its genetic makeup to avoid our immune system or develop resistance against anti-HIV drugs. HIV can also infect and kill immune cells in our body. As a result, these immune cells will no longer be able to participate in the fight against HIV.” Combined antiretroviral therapy (cART) is currently the only treatment for HIV. cART uses a mix of different antiviral drugs to stop HIV replicating. “cART targets the virus at several key stages of its infection and replication cycle. By doing so, cART reduces the amount of virus in the body to undetectable levels, thereby protecting and preserving these cells and the host's immune system,” said Dr. Jamie Mann, senior lecturer in vaccinology and immunotherapy at the University of Bristol. “When HIV infects T cells, on rare occasions, rather than the virus replicating and killing the host cell, the virus becomes dormant. In this dormant state, the virus is not susceptible to cART and can exist for a very long time.” Although cART is the main treatment for those living with HIV, this therapy cannot eradicate the latent reservoirs developed by the virus, so the treatment must be ongoing to be effective. While necessary, long-term use of cART is associated with toxicity and drug resistance. There is also a global disparity in access to treatments: • Approximately 10 million people living with HIV still do not have access to antiretroviral therapy. According to the 2023 UNAIDS report, only 43% of children living with HIV have access to life-saving medicine. • Over 25 million people living with HIV at the end of 2022 were in Africa. Gender inequalities continue to make an impact on the HIV/AIDS response, particularly in sub-Saharan Africa. In 2022, women in the region accounted for 63% of new infections. Worldwide, this figure was 46%. • Adolescent girls and young women in subSaharan Africa are at a higher risk of infection than other groups, in part due to violence, stigma, discrimination and harmful laws and practices. Other factors impacting the odds of infection include unstable housing, lower levels of education, poverty and food insecurity. • Across the globe, HIV prevalence was 14 times higher among transgender people, 11 times higher among men who have sex with men, 7 times higher among people who inject drugs and 4 times higher among sex workers in 2022 when compared with adults in the general population. “Stigma, discrimination, healthcare access and treatment adherence issues will all contribute to different populations facing distinct challenges when attempting to cure HIV,” said Mann. Protecting against sexual transmission of HIV Dr. Emmanuel Ho leads a research group focused on developing and characterizing innovative drug delivery strategies, including nanomedicines, medical devices and biomaterials, for the treatment and prevention of HIV/ AIDS, among other diseases. Ho recently developed a siRNAs are non-coding doublestranded RNA molecules, typically used to silence a gene of interest. These RNA interference tools are useful in the study of gene function and can even be utilized for the treatment of diseases such as cancer. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 41 novel nanomedicine loaded with genetic material called small interfering RNAs (siRNAs) to fight HIV. “siRNAs will play an important role in the development of novel HIV therapeutics. If we can identify a ‘target’ (e.g., gene) in our body that promotes or enhances HIV infection, as long as we know the genetic sequence of the target, we can easily design siRNAs to bind and knockdown the expression of that target,” said Ho. The nanomedicine is intended to reduce the expression of CCR5 – a gene that encodes a protein expressed by T cells and macrophages, known to be an important co-receptor for HIV to enter host cells - to prevent HIV from attaching to and entering host cells. “This gene plays a role in the HIV infection process. By reducing the expression of CCR5, we hope to reduce HIV infection,” explained Ho. By releasing a second siRNA to reduce the expression of Nef, a protein produced by HIV to inhibit autophagy, the nanomedicine can reactivate autophagy to eliminate the HIV still present in the cells. As Ho explained, “If, unfortunately, HIV is still able to infect immune cells within the body, we hope that our nanoparticles can reactivate autophagy.” When administered directly into the vagina, naked siRNAs have difficulties in achieving efficient mucosal uptake due to their rapid degradation. To get around these issues, Ho’s team encapsulated the siRNA in PEGPLGA polymer nanoparticles. The nanomedicine was developed to be delivered intravaginally to protect against sexual transmission of HIV. However, intravaginal delivery can come with challenges. “In order to deliver nanoparticles to the submucosal layer where immune cells are located, it will first have to move across a layer of cervicovaginal mucus, which can trap the nanoparticles. Afterwards, it will have to penetrate across an epithelial layer. Finally, it is important to have the nanoparticles enter the appropriate cells,” explained Ho. The team plans to optimize the nanoparticle system to attempt to achieve 100% protection against infection. Looking ahead: Is a cure on the horizon? While infection with HIV is treatable, there is no cure available. Dr. Jamie Mann is interested in addressing this issue with the development of novel therapeutic and prophylactic vaccines against HIV. “The global distribution of HIV subtypes varies, with certain subtypes being more prevalent in specific regions. This variation presents unique challenges for an HIV cure, as transmission, disease progression and responses to treatments differ. Ultimately, the cost and complexity of the treatment must be such that it is easily accessible for all who require it,” said Mann. Mann recently co-led an international study to demonstrate the ability of a new therapeutic to cure HIV. The therapeutic, an HIV-virus-like particle (HLP), can reactivate the virus when dormant, rendering it susceptible to cART and the immune system. Using blood samples from 32 participants living with chronic HIV, who were on stable cART for a median of 13 years, the team found that HLP was able to specifically target just the immune cells containing latent HIV reservoir and purge these cells of their HIV. “Our data shows that divergent strains of HIV are also susceptible to the same HLP treatment, suggesting that the HLP could have global applications as a therapy,” said Mann. HLP are engineered to resemble HIV and lack a viral genome, making them incapable of causing an infection Research is driving the development of new treatments and could introduce a cure for HIV, but ending this epidemic will be a global effort. TECHNOLOGYNETWORKS.COM DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 42 or replicating. These particles can be administered by intramuscular injection. The study shows that the HLP reverses latency irrespective of the subtype of the individual’s infection. Mann and the team plan on transitioning this work from the lab to clinical trials. “These trials will allow us to rigorously evaluate the effectiveness of our strategy in a controlled setting and hopefully bring us another step closer to making a cure a reality.” Research is driving the development of new treatments and could introduce a cure for HIV, but ending this epidemic will be a global effort, requiring improved access to preventatives, therapeutics and education for at-risk groups. • ABOUT THE INTERVIEWEES Dr. Emmanuel Ho is a professor at the University of Waterloo. His research group is interested in the development and characterization of innovative drug delivery strategies including nanomedicines, medical devices and biomaterials for the treatment and prevention of HIV/AIDS, cancer and chronic wound healing. Dr. Jamie Mann is a senior lecturer in vaccinology and immunotherapy at the University of Bristol. His research centers around the development of novel therapeutic and prophylactic vaccines against mucosal pathogens such as HIV and Influenza. DRUG DISCOVERY: INNOVATIONS, CHALLENGES AND THE FUTURE OF MEDICINE 43 TECHNOLOGYNETWORKS.COM CONTRIBUTORS Blake Forman Blake pens and edits breaking news, articles and features on a broad range of scientific topics with a focus on drug discovery and biopharma. He holds an honors degree in chemistry from the University of Surrey and an MSc in chemistry from the University of Southampton. Joanna Owens, PhD Joanna Owens holds a PhD in molecular toxicology from the University of Surrey. She has over 20 years’ experience writing about a wide range of scientific topics in biosciences, pharmaceuticals and biotechnology. Kate Robinson Kate graduated from Sheffield Hallam University with a bachelor's degree in biomedical sciences in 2020. She joined the editorial team at Technology Networks in 2021. Molly Coddington Molly Coddington is a senior writer and newsroom team lead for Technology Networks. She holds a first-class honors degree in neuroscience. In 2021 Molly was shortlisted for the Women in Journalism Georgina Henry Award. Neeta Ratanghayra, MPharm Neeta Ratanghayra holds a Master’s degree in pharmacy. She currently works as a freelance medical writer specializing in developing content for the pharma, biotech and healthcare industries. Neil Versel Neil Versel is a healthcare and life sciences journalist, specializing in bioinformatics, information technology, genomics, patient safety, healthcare quality and health policy. Molly Coddington Molly Coddington is a senior writer and newsroom team lead for Technology Networks. She holds a first-class honors degree in neuroscience. In 2021 Molly was shortlisted for the Women in Journalism Georgina Henry Award. Sarah Whelan, PhD Sarah joined Technology Networks in 2022 after completing a PhD in cancer biology, where her research focused on the development of colon cancers.