The immunotherapy was also associated with fewer emergency department visits than either of the androgen pathway receptor inhibitors.
Real-world data showed that use of the immunotherapy sipuleucel-T (Provenge) during any line of treatment in men with metastatic castration-resistant prostate cancer (mCRPC) improved overall survival (OS) versus treatment regimens that included abiraterone acetate (Zytiga) or enzalutamide (Xtandi), but not sipuleucel-T.1,2
The findings from the retrospective analysis, which were published online in Advances in Therapy, showed a 41% reduction in the risk of death among patients who received sipuleucel-T compared with those who received abiraterone or enzalutamide, but not the immunotherapy. The median OS was improved by 14.5 months with sipuleucel-T (hazard ratio, 0.59).
"Based on our analysis, men with mCRPC who received sipuleucel-T had a significant improvement in median overall survival and reduction in the risk of death at three years, regardless of line of use," lead study author Rana R. McKay, MD, a medical oncologist and assistant professor of medicine at Moores Cancer Center, University of California, San Diego, stated in a press release. "These data contribute to a growing body of evidence demonstrating the real-world effectiveness of sipuleucel-T in the mCRPC patient."
The retrospective cohort analysis included data from Medicare claims for 6044 fee-for-service beneficiaries treated between 2013 and 2017. The average age was 75-78 years, and more than 80% were white. The analysis included 2 comparisons. The first compared men treated with sipuleucel-T during some line of treatment, as well as any other approved mCRPC agent, compared with those treated with one of the androgen pathway receptor inhibitors (ARPIs) enzalutamide or abiraterone during any line of treatment, as well as any other agent except sipuleucel-T.
The other comparison was for men who received first-line sipuleucel-T versus those treated with first-line abiraterone or enzalutamide. In subsequent lines, men in either one of these groups could receive any other approved mCRPC agent. Men in the frontline ARPI arm could receive sipuleucel-T in the second-line or later.
The paper included data for the frequency of mCRPC agents used through 5 lines of treatment. In the first-line, the breakdown was sipuleucel-T (10.8%), enzalutamide (24.3%), abiraterone (55.9%), docetaxel (8.7%), and cabazitaxel (Jevtana; 0.3%). The second-line breakdown was sipuleucel-T (4.8%), enzalutamide (48%), abiraterone (24.5%), docetaxel (15.5%), cabazitaxel (1.2%), and radium-223 (Xofigo; 6%). Sipuleucel-T was used by 3.8%, 5.2%, and 0% of patients in the third-, fourth-, and fifth-lines, respectively.
For the first comparison, the median OS was 35.2 months for the any-line sipuleucel-T group versus 20.7 months for the any-line abiraterone or enzalutamide—but no sipuleucel-T—cohort. For the second comparison, first-line sipuleucel-T reduced the risk of death by 44% compared with first-line abiraterone or enzalutamide, with a median OS of 34.9 months versus 21.0 months, respectively (hazard ratio, 0.56).
The paper did not include a full safety analysis, but did provide data on emergency department visits. The average number of all-cause emergency department visits per 100 patients during the first year of treatment was lowest for men receiving sipuleucel-T at 164.3 visits, versus 194.5 and 206.4 visits for enzalutamide and abiraterone, respectively. The average number of prostate cancer–related visits was 11.6, 16.0, and 14.1, respectively.
"This analysis underscores the importance of using complementary mechanisms of action to maximize patient survival outcomes and highlights the critical role immunotherapy plays in the modern era of mCRPC treatment," Bruce A. Brown, MD, chief medical officer at Dendreon, stated in the press release.
1. McKay RR, Hafron JM, Ferro C, et al. A retrospective observational analysis of overall survival with sipuleucel-T in Medicare beneficiaries treated for advanced prostate cancer [published online October 7, 2020] Adv Ther. doi: 10.1007/s12325-020-01509-5.
2. Real-World Evidence Shows Adding PROVENGE® (sipuleucel-T) to Advanced Prostate Cancer Treatment Regimen Prolonged Median Survival by 14.5 Months. Dendreon. Published October 14, 2020. Accessed October 14, 2020. https://yhoo.it/3lMD5GS