Dr. Lee Highlights Key Takeaways From SPARTAN Trial in M0CRPC

Richard (Rick) JaeBong Lee, MD, PhD, medical oncologist at Massachusetts General Hospital, and assistant professor of medicine at Harvard Medical School, highlights key takeaways from the phase III SPARTAN trial in nonmetastatic castration-resistant prostate cancer (M0CRPC).

For the trial, investigators evaluated the use of apalutamide (Erleada) compared with placebo in a very similar design as the phase III ARAMIS trial with darolutamide. This trial also enrolled patients who had N1 disease, so some patients had lymph nodes, says Lee. Results showed an improvement in metastasis-free survival (MFS) of about 24 months. Specifically, MFS was 40 months with apalutamide versus 16 months with placebo.

A distinguishing feature of the trial was that patients who received either placebo or apalutamide were offered to receive abiraterone acetate (Zytiga) and prednisone at time of progression, he adds. Investigators also looked at another exploratory endpoint referred to as progression-free survival (PFS)2, which was defined as the time from randomization to progression on the second-line therapy, explains Lee. In terms of PFS2, patients randomized to apalutamide still had a benefit compared with those who received placebo and then went on to receive a second therapy, which was abiraterone for most patients.

The reason this is interesting is because some have argued that perhaps these drugs that are given in this space—which didn’t have any FDA approved therapies—may not necessarily impact the overall survival (OS) or the overall care for these patients, Lee says. However, what was seen by sustaining PFS2 is that the benefit from apalutamide may still be seen in the patients even when they’re given subsequent therapies. Patients who received placebo don’t necessarily have a catch-up in terms of their clinical benefit once they’re given an effective therapy after having received placebo. That’s important, says Lee.

As a field where several therapies have been shown to improve OS, and in other cancers as well, concepts like PFS2 are of particular interest, explains Lee, perhaps as another way to define how the different drugs are distinct from each other.