Evolving Treatment Patterns in mHSPC: Shifts in ARPi and Triplet Use

Announcer:
Welcome to On the Frontlines of Prostate Cancer on ReachMD. On this episode, we’ll hear from Dr. Daniel George, who’s not only the Eleanor Easley Distinguished Professor of Medicine, Surgery, and Urology at Duke University, but he’s also an American Cancer Society Impact Research Professor and practicing GU oncologist at Duke Cancer Institute. He’ll be discussing his recent study, which explored how the use of combination treatment for metastatic hormone-sensitive prostate cancer, or mHSPC for short, has changed in real-world clinical practice. Here's Dr. George now.

Dr. George:
So when I treat patients with metastatic hormone-sensitive prostate cancer, or mHSPC, for the past eight years now, we’ve been using combinations of either docetaxel or androgen receptor pathway inhibitors or a combination of both drugs with ADT for the majority of our patients with this disease setting, and the reason is based on multiple clinical trials of level 1 evidence from randomized phase 3 studies showing a survival benefit associated with combination therapy versus ADT alone. But what was interesting to me has been a relatively slow uptake.

So this most recent study that we did was really to look at the most recent data around this question, and that came from a separate resource: an administrative claims database from Komodo dating from January 2016 all the way to September 2023. And it really allowed us to look in a large population of patients now extending to a much more recent timeframe at the treatment patterns around the first four months of treatment for patients with metastatic hormone-sensitive prostate cancer. It included over 10,000 individuals. The median age was 65, and we used an index date for the evidence of patients developing castration resistance as a way of identifying their earliest onset, first for claims from metastasis and then evidence of castrate resistance, so we could frame the timeframe of metastatic hormone-sensitive disease. We used the earliest claim for ADT after that metastatic date, and then we used the combination—the addition of an ARPi, which was either abiraterone, enzalutamide, apalutamide, or darolutamide, and docetaxel chemotherapy for chemotherapy—or both with ADT within four months of that first use of ADT. And then we used multinomial regression to examine the factors associated with combination therapy, including key factors like age, chronic comorbidities, and de novo metastatic hormone-sensitive disease versus recurrent metastatic disease and, of course, the presence of bone metastasis in particular.

And the majority of patients that met the metastatic hormone-sensitive prostate cancer setting were de novo—62 percent—and overall, 28 percent of our patients through this timeframe from 2016 all the way to September 2023 received combination therapy with an ARPi. Eighteen percent were with abiraterone, and 10 percent were with apalutamide, darolutamide, or enzalutamide, so the majority received abiraterone. Only 9 percent of patients received docetaxel, and only 2.5 percent received the combination of an ARPi and docetaxel. And we did see the use of ARPis increase from 2017 to 2023 from 13 percent up to 47 percent, and with an ARPi and docetaxel, that actually went from 0.8 percent up to 15 percent. So just in this last year in 2023, we’re starting to see this spike in the combination of ARPi and docetaxel, whereas the use of ADT and docetaxel alone—no ARPi—declined from 12 percent all the way down to 3 percent, and the use of ADT alone went from 74 percent down to 36 percent. So I think all of these things suggest that the field is moving in the right direction, and I’m encouraged by the fact that in this last year we saw this really significant bump in the triplet of ARPi and docetaxel.

Announcer:
That was Dr. Daniel George talking about his study on how the utilization of combination treatment for mHSPC has changed in recent years. To access this and other episodes in our series, visit On the Frontlines of Prostate Cancer on ReachMD.com, where you can Be Part of the Knowledge. Thanks for listening!