DNA Vaccines Offer a New Path Beyond mRNA Technology
Can DNA vaccines outlast and outperform mRNA? IMUNON’s PlaCCine platform could be the future of pandemic preparedness.
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The COVID-19 pandemic reshaped how the world views vaccine development, disease preparedness and public health innovation. Nearly five years on from the global emergency declaration, it’s clear that rapid, adaptable vaccine platforms and broader population testing are essential in responding to emerging threats.
At IMUNON, a clinical-stage biotechnology company, these lessons became the catalyst for a bold pivot – adapting their existing Theraplas® DNA-based immunotherapy technology into a next-generation vaccine platform: PlaCCine®.
In this interview, Technology Networks talked to Dr. Stacy Lindborg, president, chief executive officer and board member at IMUNON, Inc., who shares how its PlaCCine platform could reshape vaccine development, the results of its first human trial and why the company is now seeking partners to advance this promising DNA-based alternative to mRNA.
What are some of the main lessons we have learned from the COVID-19 pandemic? And how does IMUNON hope to address them?
Stacy Lindborg, PhD (SL):
As we reflect on five years since the COVID-19 emergency declaration, the pandemic taught us key lessons: it exposed the need for adaptable, rapid-response vaccine platforms and highlighted the importance of testing in diverse populations. IMUNON seized this chance to adapt our TheraPlas DNA-based immunotherapy platform into PlaCCine, a new vaccine technology, using COVID-19 as a proving ground.
Our data shows that PlaCCine triggers immune responses in previously vaccinated or infected humans, COVID-naïve and COVID-exposed animals, like non-human primates – establishing proof of concept. However, we’ve also learned it would be useful to test in naïve subjects – those without prior exposure – to fully assess its potential, a step we couldn’t take during peak pandemic conditions.
IMUNON is seeking partnerships to refine PlaCCine and explore its promise as a next-generation vaccine platform, building on these insights to enhance flexibility and effectiveness for future health crises.
IE:
SL:
IMUNON chose a DNA-based approach for COVID-19 because it builds on our expertise in DNA therapeutics and offers distinct advantages over mRNA and traditional vaccines. We saw an opportunity to create PlaCCine, a platform that leverages DNA’s unique strengths.
Unlike mRNA vaccines, PlaCCine uses plasmid DNA, which is more flexible – allowing us to encode multiple antigens from one or different pathogens in a single vector. IMUNON’s preclinical data and published literature show that DNA drives longer-lasting antigen expression, giving the immune system extended exposure compared to mRNA’s shorter window. This also boosts stronger, more sustained cellular immunity, critical for long-term protection. Plus, DNA vaccines are far more stable: PlaCCine can last up to a year at 4°C or a month at 37°C, while mRNA requires ultra-cold storage.
In short, PlaCCine combines our DNA know-how with a practical, durable alternative to mRNA, aiming for versatility and resilience in vaccine design.
IE:
What were the main findings from the Phase I trial on IMNN-101?
SL:
We recently announced results from our first Phase I proof-of-concept clinical trial evaluating IMNN-101 as a potential seasonal COVID-19 vaccine, targeting the SARS-CoV-2 Omicron XBB1.5 spike antigen. In this study, 24 healthy volunteers – previously vaccinated against XBB1.5 – received a single intramuscular dose of IMNN-101 with no booster. The trial met its primary endpoint.
The key findings we highlight are: it’s safe with no serious side effects, it triggers a robust immune response after just one shot, no devices or viral vectors are needed and it stays stable at standard refrigeration temperatures (up to 4°C) for a year. These results highlight IMNN-101’s potential as a simple, effective and practical vaccine option.
IE:
Could you explain the cross-reactivity of IMNN-101 and its ability to protect against newer variants?
SL:
The Phase I trial shows IMNN-101 is cross-reactive with newer variants, demonstrating its breadth of protection. IMNN-101 was targeted against the XBB1.5 SARS-CoV-2 variant, however, it was cross-reactive against all newer variants tested, including JN.1, KP.2, KP.3, KP3.1.1 and L.B.1, generating a protective immune response.
IE:
What are the next steps for IMNN-101? Will there be a Phase II trial and what will it focus on?
SL:
The next steps for IMNN-101 hinge on securing a partnership to advance its development beyond the successful Phase I trial, which confirmed its safety, immunogenicity and stability as a potential seasonal COVID-19 vaccine and proof-of-concept for broader application. We’re actively seeking collaborators who see IMNN-101’s value as a flexible, stable, easy-to-store and potentially more durable alternative to mRNA vaccines. With the right partnership, we aim to drive IMNN-101 through Phase II and into late-stage trials, targeting eventual clinical use.
IE:
Beyond COVID-19, what other pathogens or diseases is IMUNON considering for vaccine development using the PlaCCine platform?
SL:
The PlaCCine platform’s success with IMNN-101 against COVID-19 highlights its potential to tackle other infectious diseases, thanks to its ability to trigger strong immune responses and encode multiple pathogen targets in one vaccine. This platform could have many uses. Beyond COVID-19, high-priority pathogens with unmet needs could include influenza, respiratory syncytial virus, human immunodeficiency virus (HIV), Ebola, cytomegalovirus (CMV) and emerging threats like dengue or Zika – viruses where vaccines are either absent, suboptimal or hard to distribute due to stability issues. Since 1980, over 80 new pathogenic viruses have been identified, yet fewer than 4% have commercially available vaccines, making this a critical space for innovation.
While our immediate focus remains on advancing IMNN-101 with potential partners, we’re actively evaluating PlaCCine’s broader applications, targeting diseases where its flexibility and stability could fill gaps left by traditional platforms.
