Daniel P. Petrylak, MD, discusses background and findings from the phase 3 KEYNOTE-921 study of pembrolizumab plus docetaxel vs placebo plus docetaxel in patients with metastatic castration-resistant prostate cancer who had received prior next-generation hormonal agent therapy.
Daniel P. Petrylak, MD, professor of medicine and urology at Yale School of Medicine, and co-leader, Cancer Signaling Networks, Yale Cancer Center, discusses background and findings from the phase 3 KEYNOTE-921 study (NCT03834506) of pembrolizumab (Keytruda) plus docetaxel vs placebo plus docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC) who had received prior next-generation hormonal agent therapy.
In the randomized, double-blind, phase 3 study, the efficacy and safety of the 2 combinations were evaluated in 1030 patients with mCRPC. Patients were randomized in a 1:1 fashion to receive pembrolizumab with docetaxel (n = 515) or placebo with docetaxel (n = 515). In the experimental arm, 200 mg of pembrolizumab was given every 3 weeks for up to approximately 2 years plus 75 mg/m2 of docetaxel and 5 mg of prednisone twice daily for approximately 7 months. Patients in the placebo arm received docetaxel and prednisone on the same schedule.
According to Petrylak, adding pembrolizumab to docetaxel did not significantly improve radiographic progression-free survival or overall survival among this patient population. The results of this trial serves as an important reminder that metastatic disease remains difficult to treat, and that further research is warranted.
0:10 | The background of this study was the fact that there was a phase 2 trial that was performed, combining pembrolizumab with docetaxel, and it showed a median survival of about 19 months. In the past, when patients received abiraterone as frontline therapy, and then received docetaxel afterwards, the median survival was about 13 months. The thought was that this was an improvement over the median survival that had been previously reported since all these patients had received 1 prior novel hormonal agent.
0:49 | The randomized study of 1030 patients, straight 1:1 randomization, of pembrolizumab combined with docetaxel vs docetaxel alone. In the trial, we saw no difference in the overall survival or progression-free survival, radiographic progression-free survival, for patients treated with the combination. Unfortunately, pembrolizumab does not change the standard of care as a combination therapy with docetaxel.