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Conversations With Prostate Cancer Experts


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Genomics, Predicting Side Effects, + Clinical Trial Design

Dr. Felix Feng is a physician-scientist at University of California, San Francisco (UCSF) keenly interested in improving outcomes for patients with prostate cancer.

His research centers on discovering prognostic/predictive biomarkers in prostate cancer and developing rational approaches to targeted treatment for therapy-resistant prostate cancer. He also sees patients through his prostate cancer clinic at UCSF.

Prostatepedia spoke with him about genomics, predicting side effects and the future of prostate cancer clinical trials

Can genomics predict who will have certain side effects?

Dr. Feng: There have been a number of studies that have used single nucleotide changes within DNA sequences, called single nucleotide polymorphisms (SNPS), to predict who will be most likely to experience side effects from radiation therapy for cancer.

In general, the signal from these toxicity studies has been weaker than the signals from biomarkers that predict responses to particular therapies, like the ones that I mentioned earlier. This may be reflective of the fact that radiation acts through a variety of mechanisms, so any single biomarker may not work well. Even when you cluster biomarkers, it may not account for the heterogeneous manner in which radiation causes a biological effect.

What should patients know about how genomics is impacting treatment?

Dr. Feng: Many of the clinical trials being developed nowadays incorporate genomics. We have clinical grade assays to look at genomics. We have strong biological rationale for why certain genomic biomarkers may identify subsets of patients who can respond to specific therapies. Because genomics is routinely used to personalize treatment in the context of diseases like breast cancer, colon cancer, and melanoma, it’s only expected that genomics will have a major role in prostate cancer going forward.

Will incorporating genomics into clinical trial design accelerate the speed of innovation?

Dr. Feng: I think it will. If you look at metastatic castration-resistant prostate cancer, for example, a number of therapies have been approved by the FDA over the last decade for those patients, including agents like Zytiga (abiraterone) and Xtandi (enzalutamide), next generation taxanes, Provenge (sipuleucel-T), and Xofigo (radium-223). All of these agents extend survival by just a few months.

This is invariably what happens when you treat prostate cancer as one disease entity rather than a variety of different entities that are governed by different genomic events. As we become better at selecting therapies based on a patient’s genomic events, we should see longer response times to available therapies and those currently being developed.

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