Dr. Antonarakis on Updated Analysis of the KEYNOTE-199 Trial in mCRPC

Emmanuel S. Antonarakis, MBBCh, professor of oncology, Johns Hopkins Medicine, discusses updated data from the phase II KEYNOTE-199 trial in metastatic castration-resistant prostate cancer (mCRPC).

KEYNOTE-199 is a multicohort trial that evaluated pembrolizumab (Keytruda) across 5 cohorts. In cohorts 1-3, investigators evaluated pembrolizumab monotherapy in patients with mCRPC who had previously received docetaxel. In cohorts 4-5, investigators evaluated the combination of pembrolizumab and enzalutamide (Xtandi) in patients with mCRPC who were progressing on enzalutamide.

Extended follow-up from cohorts 1-3 showed an objective response rate of 3% to 6% per blinded independent central review criteria, which is consistent with initial findings, says Antonarakis. Moreover, no new safety signals were reported with pembrolizumab. Given the modest activity of pembrolizumab monotherapy, investigators will evaluate the drug in combination with either enzalutamide, docetaxel, or olaparib (Lynparza), concludes Antonarakis.