Circulating tumor cells: Ready for Prime time?- Howard Scher
Howard Scher discusses the readiness of liquid biopsy and the process required to make the possibilities of predictive biomarkers a reality. What is needed are assays for predictive biomarkers in circulating tumor cells (CTCs) to inform choice of the treatment at decision points in patient management. He discusses the challenges in demonstrating clinical utility which is the use of the test results to direct management improves patient outcomes (benefits exceed harms) compared to no use of the test. He illustrates the barriers to standardization and regulatory approvals. (Presentation in 15.45 minutes).
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Howard I. Scher, MD. is Chief of the Genitourinary Oncology Service at the Sidney Kimmel Center for Urologic and Prostate Cancers at Memorial Sloan Kettering and a board-certified medical oncologist with special expertise in treating men with advanced prostate cancer. Under his leadership, the Genitourinary Oncology Service program is dedicated to the treatment of prostate cancer, testicular cancer, bladder and upper-tract urothelial cancer, and kidney cancer. Their objective is to foster synergy between scientific research and clinical practice, and to ensure that promising scientific discoveries are used to develop new diagnostic tests and treatments for patients.
His research is focused on three critical areas: developing treatments that target specific signaling pathways that contribute to prostate cancer growth, developing non-invasive methods to determine whether these agents are working, and improving the way drugs are evaluated in the clinic.
Targeted therapies, which attack specific cancer cells without harming normal cells, have the potential to treat cancers with fewer side effects than conventional therapies. Critical to the development of this approach, is to determine which treatment is most likely to be benefit an individual patient. Currently, prostate-specific antigen (PSA) is the best routinely available biomarker providing diagnostic and prognostic information about prostate cancer. PSA testing is useful, but does not reliably determine whether or not a treatment is working, nor does not provide definitive guidance in selecting one therapy over another. He and his colleagues are evaluating promising new technologies to capture and characterize circulating tumor cells from a routine blood draw. They are finding that the number of circulating tumor cells in a patient’s blood helps determine a patient’s prognosis and whether or not a treatment is working. Circulating tumor cells are also providing a biological snapshot of an individual patient’s tumor, which may help determine the choice of therapy.
As a member of the Prostate Cancer Clinical Trials Working Group, he has led an international effort to standardize development of the design, conduct, and analysis of phase 2 clinical trials in prostate cancer, so they can better evaluate new therapeutics and assess their effectiveness using novel imaging modalities. The recommendations were incorporated and contributed to the successful development of ZYTIGA and enzalutamide, both FDA approved. Both of these agents target androgen receptor signaling and were shown to prolong the survival of men with castration-resistant disease. He also developed the Clinical States Model of Prostate Cancer Progression, which, in categorizing the clinical spectrum of prostate cancer from diagnosis to metastasis, provides a framework to access and reassess a patient’s prognosis as the disease evolves over time and to guide management of the disease.
He is also the principal investigator of the Memorial Sloan Kettering Prostate Cancer SPORE (Specialized Program on Research Excellence) sponsored by the National Cancer Institute and Principal Investigator of the Prostate Cancer Clinical Trials Consortium, a 13-center research collaborative headquartered at Memorial Sloan Kettering and funded by the Department of Defense and the Prostate Cancer Foundation. A critical part of this effort is to design and conduct clinical trials of promising new approaches so that they are available to patients as soon as possible. Since 2006, the consortium has facilitated more than 120 new early-phase studies related to prostate cancer. Ultimately, through these clinical trials, they seek to develop more-effective treatments for prostate cancers of all stages and to discover means of prevention.
In addition to serving as Chief of the Genitourinary Oncology Service for the past 16 years, he is the incumbent of the D. Wayne Calloway Chair in Urologic O