Dr. Choudhury on Future Research Directions for Pembrolizumab/Radium-223 in mCRPC

Atish D. Choudhury, MD, PhD, co-director of the Prostate Cancer Center and senior physician at Dana-Farber Cancer Institute, as well as an instructor in medicine at Harvard Medical School, discusses future research directions for the combination of pembrolizumab (Keytruda) and radium-223 (Xofigo) dichloride in patients with metastatic castration-resistant prostate cancer (mCRPC).

There are ongoing efforts to indentify combination strategies to increase the efficacy of Immunotherapeutics for patients with mCRPC, Choudhury says. As such, dense profiling of tumor tissue and cell-free DNA specimens will be conducted for patients enrolled on the phase 2 (NCT03093428) trial, which examined the combination of pembrolizumab and radium-223 vs radium-223 alone, to better understand if there are any correlates for the patients who experienced longer progression-free survival compared with those who experienced quicker disease progression with the combination, Choudhury explains.

Additionally, because the combination was well tolerated among patients who enrolled on the phase 2 study, it is possible that a third agent could be added to observe whether further clinical activity can be achieved, Choudhury notes. Currently, however, the doublet combination does not show any additional benefit in this patient population over treatment with radium-223 alone, Choudhury concludes.