Findings ‘useful for clinicians’
“The findings from PROCEED are useful for clinicians in discussing treatment options with patients, particularly those with a low PSA. Considering the prognosis for a man with mCRPC, the median survival of nearly 4 years in men treated with sipuleucel-T when their PSA was low is compelling in suggesting a positive outcome when immunotherapy is given earlier when baseline PSA is lower,” Dr. Higano told Urology Times.
“It is also important to note that the mCRPC treatment space evolved rapidly after the phase III IMPACT trial investigating sipuleucel-T was conducted. Findings from data collected in PROCEED shed new light on the safety and survival outcomes that can be expected when these new therapies are used before and following treatment with sipuleucel-T,” she said.
A total of 338 men (17.8%) received an OS-prolonging anticancer intervention (abiraterone [ZYTIGA], enzalutamide [XTANDI], docetaxel [Taxotere], cabazitaxel [Jevtana], or radium 223 [Xofigo]) before sipuleucel-T, and 1,483 men (78%) received one or more anticancer interventions following receipt of sipuleucel-T.
Dr. Higano observed that the findings from PROCEED showing better survival outcomes among men treated earlier with immunotherapy when their PSA was lower are consistent with results from the pivotal phase III IMPACT trial. A post hoc analysis of IMPACT data showed men with mCRPC who received sipuleucel-T when their PSA was <22.1 ng/mL had a median OS of 41.3 months, which represented an improvement of 13 months compared to the median OS for the men in the same PSA grouping in the untreated control group.
The safety outcomes recorded in PROCEED were also consistent with the safety profile of sipuleucel-T in the phase III study. In PROCEED, a serious adverse event related to sipuleucel-T occurred in 3.9% of patients; the most common of these events were chills (0.7%) and cerebrovascular accident (0.5%). Overall, a cerebrovascular event occurred in 2.8% of patients, which translates into a rate of 1.2 per 100 person-years. Analysis of data from the Surveillance, Epidemiology, and End Results-Medicare database show a cerebrovascular event rate of 1.5 per 100 person-years among men with mCRPC.
Dr. Higano has served in an advisory role for Aptevo, Asana, Astellas, Bayer, Blue Earth Diagnostics, Churchill Pharma, Clovis Oncology, Dendreon, Endocyte, Ferring, Medivation, Orion Corp., and Pfizer; she has also participated in sponsored research for Aptevo, Bayer, Aragon Pharma, Astellas, AstraZeneca, Dendreon, Genentech, Hoffman-LaRoche, Medivation, Sanofi, and Pfizer, and her spouse was in a leadership role for CTI Biopharma.