The FDA approved apalutamide for the treatment of patients with metastatic castration-sensitive prostate cancer (mCSPC). The approval follows FDA Priority Review Designation of the supplemental New Drug Application (sNDA) that was submitted in April 2019 and reviewed through the FDA Real-Time Oncology Review program. The new indication for apalutamide will make this androgen receptor inhibitor available for the approximately 40,000 people in the U.S. diagnosed with mCSPC annually.
Approval is based on results from the Phase III TITAN study, which achieved statistical significance in the dual primary endpoints of overall survival (OS) and radiographic progression-free survival (rPFS) at the first pre-planned interim analysis. The trial recruited patients regardless of extent of disease, including both high- and low- volume disease, or prior docetaxel treatment history. Results were presented in an oral session at the 2019 ASCO Annual Meeting and simultaneously published in The New England Journal of Medicine (2019; doi: 10.1056/NEJMoa1903307).
"Prostate cancer is more difficult to treat once it spreads, and for patients with castration-sensitive disease, it is clear that androgen deprivation therapy (ADT) alone, is often not enough," said Kim Chi, MD, Medical Oncologist at BC Cancer - Vancouver and principal investigator of the TITAN study. "Results from the TITAN study showed that, regardless of the extent of disease, patients with metastatic castration-sensitive prostate cancer have the potential to benefit from treatment with apalutamide in addition to ADT."
In the TITAN study, apalutamide plus ADT significantly extended OS compared to placebo plus ADT with a 33 percent reduction in the risk of death (HR=0.67; 95 percent CI, 0.51-0.89; P=0.0053). Apalutamide plus ADT also significantly improved rPFS compared to placebo plus ADT with a 52 percent lower risk of radiographic progression or death (HR=0.48; 95 percent CI, 0.39-0.60; P<0.0001). As reported in the published results from the TITAN study, the two-year OS rates, after a median follow-up of 22.7 months, were 84 percent for apalutamide plus ADT compared to 78 percent for placebo plus ADT.
The most common adverse reactions (≥10 percent) that occurred more frequently in apalutamide treated patients (≥2 percent over placebo) from the randomized placebo-controlled clinical trials (TITAN and SPARTAN) were fatigue, arthralgia, rash, decreased appetite, fall, weight decreased, hypertension, hot flush, diarrhea, and fracture.