Published findings from PROCEED, a large registry collecting data from men treated with sipuleucel-T (Provenge) for asymptomatic/minimally symptomatic metastatic castration-resistant prostate cancer (mCRPC), provide valuable insight on real-world outcomes associated with this immunotherapy agent in the modern era of prostate cancer management.
The report, published in Cancer (Sept. 4, 2019 [Epub ahead of print]), included data from 1,976 patients who were entered into the registry between 2011 and 2014, of whom 1,902 received one or more sipuleucel-T infusions. The analysis, which was based on a median follow-up of 46.6 months, showed that a substantial proportion of men had a long interval between sipuleucel-T and subsequent therapy; 32.5% of patients experienced a 1-year treatment-free interval and 17.4% of men had a 2-year treatment-free interval, said lead author Celestia S. Higano, MD, professor of medical oncology, department of medicine, University of Washington School of Medicine and Fred Hutchinson Cancer Research Center, Seattle.
Median overall survival (OS) after receipt of the immunotherapy was 30.7 months; median time from first sipuleucel-T infusion to prostate cancer-related death was 42.7 months.
A post hoc analysis identified a benefit from earlier initiation of immunotherapy. Median PSA at enrollment for the entire cohort was 15.0 ng/mL, and stratification of men into quartiles by baseline PSA level showed median OS decreased with increasing PSA. Within the lowest PSA quartile (≤5.27 ng/mL), median OS was 47.7 months, and 44% of men did not receive any additional cancer treatments for at least 1 year. Nearly all of the latter men were treated with sipuleucel-T as first-line therapy as recommended by the National Comprehensive Cancer Network, said Dr. Higano.