Management of Advanced Prostate Cancer in Urology: Update on Androgen Receptor Inhibitors - Episode 9
Vivek K. Narayan, MD, MS, reviews data from the SPARTAN trial in nmCRPC and discusses the importance of assessing health-related quality of life.
Neal Shore, MD, FACS: Vivek, if you could please give us a review on SPARTAN, and then we can talk about these 3 excellent drugs that met their initial primary end point of MFS [metastasis-free survival] and then all 3 went on to demonstrate key OS [overall survival] benefit as a secondary end point. And after, Vivek, if you review SPARTAN for us and the great work that was led by Eric Small [Eric Small, MD] and Matt Smith [Matthew Smith, MD, PhD] as well as Kim Chi [Kim Chi, MD] who led the TITAN study, and then we can discuss if there are any nuanced differences in tolerability? Are there any nuanced differences in the MFS and/or the OS? And how do we decide on this? And then we’ll get back to Ash’s point about, what if PSMA [prostate-specific membrane antigen] PET [positron emission tomography] is invoked? And how are we going to get accessibility in the US? We’re catching up to our German, Australian, and some of our other colleagues around the world in having that new advanced imaging. But Vivek, maybe take us through SPARTAN.
Vivek K. Narayan, MD, MS: SPARTAN was a similar study design to what Bobby had described for both PROSPER and ARAMIS, a randomized phase 3 placebo-controlled study, this time of apalutamide [Erleada] in the setting of nonmetastatic CRPC [castration-resistant prostate cancer]. Patients were randomized 2:1 to either apalutamide or the placebo. And the primary end point was MFS, and it was clearly met in favor of the apalutamide treatment arm. There was a median 2-year improvement in MFS relative to placebo, a very meaningful improvement in that primary outcome. And then very similar to the other studies, with longer follow-up, this time with a median of around 3.5 years, there was a demonstrated improvement in overall survival with a hazard ratio of about 0.75. One important point about the overall survival that is worth highlighting is that at the time of unblinding for these studies, including the SPARTAN study, there was crossover in the placebo arm to active therapy for nonmetastatic castration-resistant prostate cancer. And despite that crossover to active therapy in those men who were initially on placebo, there’s still this demonstrated benefit in overall survival even after accounting for this crossover. And that’s an important point and drives home the survival benefit that was observed in these studies. The other thing I would underscore is what Ash alluded to earlier about the importance of health-related quality of life in this particular setting, which was also seen in the SPARTAN study, where the men had relatively preserved quality of life metrics over the course of study treatment. And in the placebo arm, it appeared to decline over time, largely probably related to the manifestations of progressing prostate cancer. But in this setting, where the treatment intent is palliative and men are asymptomatic or minimally symptomatic by virtue of nonmetastatic disease, this importance of treatment-related adverse events is critical in mitigating that as much as possible. It was very reassuring to see preserved quality of life metrics with longer-term follow-up.
Neal Shore, MD, FACS: Super important. First, do no harm. That’s the Hippocratic Oath. And you have a typically elderly man. The median age of SPARTAN, PROSPER, ARAMIS was 74. And they’ve already been on chronic ADT [androgen deprivation therapy]. They have no obvious disease on conventional imaging. We’re treating them because of all those studies had a PSA [prostate-specific antigen] doubling time of less than or equal to 10 months. The labels don’t include that, but that was the study. And now, you’re going to add another drug. And you’ve got to talk to the patients. And they’re going to say, “Well, what about adverse effects? Is my father, grandfather, husband going to have a problem here?”
Transcript Edited for Clarity