Improving Prostate & Bladder Cancer Diagnosis
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Arquer Diagnostics has recently been awarded £70,000 funding under Innovate UK's Biocatalyst programme, to evaluate the use of their MCM5 ELISA-based test for prostate cancer detection. A variation of the non-invasive test has already shown promise as a tool for bladder cancer diagnosis, and will be launched in the second half of this year in the EU.
To learn about some of the limitations of current methods of diagnosing prostate and bladder cancers, and how the MCM5 ELISA-based tests could help improve the process, I spoke to Nadia Whittley, CEO Arquer Diagnostics.
AM: What are some of the limitations of current methods of diagnosing bladder cancer?
NW: In the UK, for patients presenting with symptoms such as blood in the urine (haematuria) the conventional pathway includes urine tests such as urine cytology and subsequently flexible cystoscopy (trans-urethral bladder endoscopy); in some instances urologists may also request imaging such as computed tomography. Cystoscopy is an invasive and unpleasant procedure which has quite a considerable cost associated.
It is a well-known fact that, on average, only 10% of haematuria patients will be diagnosed with bladder cancer. In addition, cystoscopy fails to detect approximately 25% of bladder tumours; this can be due to the inability to properly visualise the entire interior surface of the bladder, or the difficulty in identifying cancers that have particular shapes, making it difficult to differentiate from normal tissue, particularly in the presence of inflammatory tissue. Finally, the cystoscope is unable to ‘see’ the interior of the ureters where lesions can occur.
There are a few urine based biomarker tests available, such as NMP22, however they have poor sensitivity and specificity, in other words they fail to detect a number of bladder tumours, while giving false positive results in many cases.
AM: What are some of the limitations of current methods of diagnosing Prostate cancer?
NW: Prostate cancer is a major healthcare challenge in the UK with 47,000 patients diagnosed every year. Currently the only screening tool for prostate cancer is the prostate specific antigen (PSA) blood test, a seriously flawed test which, in a large population study, missed 75% of biopsy detectable cancers. In addition, the test has a false positive rate of up to 70%, resulting in a large number of unnecessary biopsies being carried out on patients with benign disease (Adhyam et al. 2012). Prostate biopsies are highly invasive, unpleasant for patients and carry the risk of infection (up to 6% of patients undergoing biopsy develop infection, of which up to 1% require hospitalisation (Lundström et al., 2014)). Reducing the number of unnecessary biopsies would result in huge savings to the NHS, and increased patient comfort. In addition, Prostate Cancer UK have identified the urgent need for a reliable screen for the over 40s.
The advantage of our test (MCM5) is that is specific for cancer, i.e. it does not detect benign disease, such as benign prostatic hyperplasia, one of the most common causes of false positive PSA tests. This could significantly reduce the number of unnecessary prostate biopsies being carried out, resulting in better treatments plans for patients and major savings to the NHS.
AM: Can you tell us more about your MCM5-ELISA test?
NW: MCM5 protein is a marker of proliferating cells usually found only in the basal layers of the epithelial layers. When a cancer is present (for example in the bladder) proliferating cells are shed into the urine. The MCM5 ELISA for Bladder Cancer (ADXBLADDER) detects the MCM5 in these shed cells using a standard ELISA methodology.
Unlike many of the current commercially available biomarkers, the specificity of ADXBLADDER is not affected by benign proliferative or inflammatory conditions, including Bacillus Calmette-Guerin (BCG) induced granulomatous cystitis. Therefore, Arquer's ADXBLADDER test is able to differentiate those patients who have a malignancy (MCM5 positive) from those with benign, inflammatory or infectious causes of haematuria (MCM5 negative).
Initial testing of the ADXBLADDER product has shown that the test has a sensitivity of 83%, which is significantly greater sensitivity than that of current biomarker tests, which were 40-53% sensitive over a subset of the same samples. This means that the test is picking up more bladder cancers than the other biomarker tests.
One other extremely important difference with current available tests is that ADXBLADDER test has a very high Negative Predictive Value (NPV) of 98%, meaning that a negative MCM5 score correlates well with a cancer negative diagnosis.
For more information please visit: http://www.arquerdx.com/wp-content/uploads/2017/02/ARQ001_Rev_A_MC5001B-012017.pdf
AM: Can the test be used in the diagnosis of other cancer types?
NW: ADXBLADDER has been developed specifically for the detection of bladder cancers in urine; we are currently planning to launch ADXPROSTATE for the detection of prostate cancer. The MCM5 protein is a marker of proliferating cells usually found only in the basal layers of epithelial layers, subsequently it is possible that the MCM5 ELISA technology could be used to sensitively and accurately identify cancers that disrupt these epithelial layers. Arquer Diagnostics has a full program of research and development looking into these applications.
AM: Can you tell us about the Innovate UK Biocatalyst programme and what your award will be used for?
NW: The award will be used to carry out our initial feasibility study for the MCM5 ELISA test in prostate cancer, as well as to validate the health economic model related to the prostate cancer diagnostic pathway, clinical/patient outcomes and costs. Also, studies will be carried out on urine and semen to optimise sample processing methods required to make the test specific for the detection of prostate cancer with maximum sensitivity.
Nadia Whittley was speaking to Anna MacDonald, Editor for Technology Networks.