CHICAGO, IL USA (UroToday.com) - Presented by Tomasz M. Beer, MD, FACS at the American Society of Clinical Oncology (ASCO) Annual Meeting - May 31 - June 4, 2013 - McCormick Place - Chicago, IL USA
Click HERE to view the poster from this session
Open-label, multicenter study of sipuleucel-T in men with metastatic castrateresistant prostate cancer (mCRPC) previously treated with sipuleucel-T: Evaluation of antigen presenting cell (APC) activation and ELISPOT data
Tomasz M. Beer, L. Michael Glode, Raymond S. Lance, Richard H. Greengold, Corazon P. dela Rosa, Robert Brownell Sims, Yang Wang, Nadeem A. Sheikh, John M. Corman
Oregon Health & Science University Knight Cancer Institute, Portland, OR; University of Colorado Denver, Aurora, CO; Eastern Virginia Medical School, Norfolk, VA; South Orange County Medical Research Center, Laguna Hills, CA; University of Washington, Seattle, WA; Dendreon Corporation, Seattle, WA; Virginia Mason Medical Center, Seattle, WA
Background: P10-1 (NCT01338012) is a study of sipuleucel-T, an autologous cellular immunotherapy, in men with mCRPC previously treated with sipuleucel-T in PROTECT (NCT00779402). This preliminary analysis of P10-1 evaluates APC activation (a measure of product potency) and immune responses in men retreated with sipuleucel-T.
Methods: Men who received ≥ 1 infusion of sipuleucel-T in PROTECT and progressed to mCRPC were retreated with 3 infusions of sipuleucel-T. APC activation was assessed by CD54 upregulation. T cell responses to prostatic acid phosphatase (PAP) and PA2024 (PAP-GM-CSF) antigens were assessed by IFN-γELISPOT assay.
Results: As of October 23, 2012, 7 men were enrolled and received ≥ 1 infusion. Median time between the third PROTECT infusion and first P10-1 infusion was 9.2 (range: 7.8 –10.0) years. APC activation was greater at the first P10-1 treatment vs the last PROTECT treatment. PA2024 and PAP ELISPOT responses were present prior to retreatment, indicating long-term memory; based on other studies of sipuleucel-T, ELISPOT responses are not generally present prior to the first treatment (Beer. Clin Cancer Res 2011; Sheikh. Cancer Immunol Immunother 2013).
Conclusions: This is the first trial to report the feasibility of sipuleucel-T retreatment following treatment in an earlier stage of prostate cancer. These data indicate the presence of existing immunological memory to the immunizing antigen several years after initial treatment. In addition, retreatment with sipuleucel-T appeared to boost product potency compared with prior treatment. Clinical trial information: NCT01338012.
Tomasz Beer, MD, completed his medical training at The Johns Hopkins University School of Medicine in 1991 and went on to complete residency training in internal medicine and fellowship training in hematology and medical oncology at Oregon Health & Science University. Dr. Beer serves as the Grover C. Bagby Endowed Chair for Prostate Cancer Research, Professor of Medicine in the Division of Hematology & Medical Oncology and Deputy Director at the Oregon Health and Science University (OHSU), Knight Cancer Institute in Portland. Dr. Beer serves as a leader of the Prostate Cancer Program of the OHSU Knight Cancer Institute and NCI-designated Cancer Center.
Dr. Beer has authored and co-authored more than 250 articles and abstracts on prostate cancer. His major research interests include clinical trials, preclinical investigation, and risk factors in prostate cancer. Dr. Beer has been involved in more than 100 clinical trials and has led studies that tested new drugs in humans, for the first time, as well as large global studies that challenge the current standard of care.
In addition to developing, carrying out and leading clinical trials, Dr. Beer is strongly interested in bringing knowledge about cancer clinical trials to people living with cancer. During the past year, Dr. Beer teamed up with Larry Axmaker, a cancer survivor and clinical trial participant to author a book entitled "Cancer Clinical Trials, A Commonsense Guide to Experimental Cancer Therapies and Clinical Trials." The author's blog is at www.cancer-clinical-trials.com.