Dr Sumit Subudhi Discusses Immune Checkpoint Inhibitors in Prostate Cancer

In prostate cancer, combination therapies are being used to see how 1 drug may trigger an immune infiltrate or proteins that allow the tumor to resist the monotherapy, said Sumit Subudhi, MD, PhD, genitourinary medical oncology, Cancer Medicine, MD Anderson Cancer Center.

Transcript (slightly modified)

Prostate cancer has had lower response rates to single-agent immune checkpoint inhibitors than other cancers. How are you working towards understanding who will have the best response to these inhibitors?

It’s been a real struggle to get the response we see in malignancies such as melanoma, kidney, and bladder. What we’re starting to understand is that the prostate cancer tumor microenvironment is just really an immunosuppressive 1, and so the strategies we’re using now is using combinations, and rational combinations, by looking to see how 1 drug may trigger an immune infiltrate or proteins that allow the tumor to resist the monotherapy.

So, for example we’ve completed a trial where we were doing ipilimumab plus anti- PD-1, and the reason for that was after giving 2 doses of ipilimumab, we found that the tumor microenvironment upregulates both PD-1 and PD-L1, so by doing the combination, we should see better responses, and so far it looks like the early signals show that. We’re getting better response, but not as well as we see in melanoma.

What we’re going to have to do is find out who are these patients that actually respond so that we can enrich that population and then also better understand why the other patients are not responding.