Apalutamide Produces Deep PSA Response vs Enzalutamide in mCSPC

Benjamin H. Lowentritt, MD, FACS, medical director of prostate cancer, a practicing urologist at Chesapeake Urology in Baltimore, Maryland, discusses findings from a United States real-world study of patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with apalutamide (Erleada) or enzalutamide (Xtandi).

According to results presented at the 2024 Genitourinary Cancers Symposium, treatment with apalutamide led to more deep and early prostate-specific antigen responses by 6 months compared with those treated with enzalutamide. By 6 months, the PSA90 response in the apalutamide arm of 860 patients was 63.9% vs 55.1% seen in the enzalutamide arm of 869 patients.

Transcription:

0:09 | What is interesting, and we have seen this in every step of the way, even as the data set has grown, which has allowed us to feel even more confident with what we are seeing, is that there does appear to be a difference in this PSA response in patients on apalutamide vs those that are on enzalutamide. Over the course of treatment, and typically, we have to be able to follow these patients out for a year in order for them to be included, but what we see, though this is this 6-month timeframe. The 6-month timeframe has, for a number of years now, been deemed sort of the critical time element for seeing a PSA response. That is true for prospective randomized trials, and the FDA has sort of determined that this is a really important timeframe to report on because it is not just the depth of response that is important, but also how quickly they get there.

1:10 | We looked specifically at patients getting at least a 90% reduction in their PSA from prior to treatment, so the so-called PSA 90, and then we also looked at different time intervals at 3 months, 6 months, etc. What we found is that there is a more rapid and a more consistently deep PSA response in those patients receiving apalutamide vs those that received enzalutamide. Over the course of the timeframe that we looked at, there was a roughly 20%-21% difference between the 2 groups as far as how many people responded. I think it is an interesting perspective to have because it really is now a fairly large dataset to be able to look at.

REFERENCE:

Lowentritt BH, Du S, Pilon D, et al. Real-world comparison of prostate-specific antigen (PSA) response in patients with metastatic castration-sensitive prostate cancer (mCSPC) treated with apalutamide (APA) or enzalutamide (ENZ). Presented at the 2024 Genitourinary Cancers Symposium; San Francisco, CA, January 25-27, 2024. Abstract 51.