GenomeDx Biosciences today announced that the robust Decipher® genomic analysis platform, successfully classified various subtypes of bladder cancer based on the genomic expression of certain biomarkers, including one type associated with resistance to cisplatin-based chemotherapy. Importantly, this unique genomic signature has potential as a tool to predict tumor responsiveness to neoadjuvant chemotherapy in patients with muscle-invasive bladder cancers (MIBC). The study was presented today at the American Society for Clinical Oncology (ASCO) 2015 Annual Meeting in Chicago.
"Approximately 80 percent of MIBC patients treated with neoadjuvant chemotherapy are treated with a cisplatin based chemotherapy, with as few as 25 percent of patients responding," said Elai Davicioni, Ph.D., president and chief scientific officer at GenomeDx and an author in the study. "Clearly, a more effective means for guiding treatment decisions is needed for this patient population. This study suggests that the genomic signature identified by our Decipher platform may help predict which patients will be resistant to treatment and should not delay surgery, and supports further investigation into the performance and utility of this signature as a predictive tool."
The study included samples from 52 bladder cancer patients who received neoadjuvant gemcitabine plus cisplatin followed by a cystectomy. Tumors were clustered into subtypes based on non-overlapping genomic expression of biomarkers, and resulted in identification of an expression pattern unique to p53-like tumors, with p53-like tumors displaying chemo-resistance. The findings were presented today by Roland Seiler, M.D., University of British Columbia, in a poster discussion titled, "p53-ness is associated with chemo-resistance in urothelial cancers treated with neoadjuvant gemcitabine plus cisplatin." The abstract is available online at http://abstracts.asco.org/156/AbstView_156_143822.html
The genomic signature was validated using GenomeDx's Decipher platform and builds on previous work conducted by Choi W et al (Cancer Cell, 2014) from MD Anderson Cancer Center, which outlined the discovery of these distinct muscle invasive bladder cancer subtypes and their sensitivity to dose dense MVAC chemotherapy. The Decipher platform has already generated a highly validated and commercially available test covered by Medicare for predicting metastasis in prostate cancer patients who have had their prostate removed.
Nearly 75,000 patients will be diagnosed with bladder cancer in 2015, the United States alone. It is the fourth most commonly diagnosed cancer in men and the twelfth in women and is projected in 2015 to account for 16,000 deaths in the US. Removal of the bladder with chemotherapy treatment before or after surgery is the standard of care for patients with muscle invasive bladder cancer. Suboptimal response rates to chemotherapy and the associated burden of treatment underscore the need to develop new tools to help identify patients who will benefit most from chemotherapy.