The US Food and Drug Administration (FDA) approved a lower dose of a previously approved therapy for prostate cancer after reviewing a post-marketing study.
Cabazitaxel is now indicated at a dose of 20 mg/m2 every 3 weeks in combination with prednisone in patients with metastatic castration-resistant prostate cancer who have received a previous docetaxel-based treatment regimen. The originally approved dosage —25 mg/m2—was approved in 2010.
Approval came following recent data from a noninferiority, multicenter, randomized open-label involving 1200 docetaxel-treated patients with metastatic castration-resistant disease. Patients received either 25 mg/m2 (n = 602) or 20 mg/m2 (n = 598) dose.
Results showed that the intent-to-treat cohorts had comparable overall survival (OS); median OS was 13.4 months for patients receiving 20 mg/m2 cabazitaxel, compared with 14.5 months for patients receiving the higher dose (HR, 1.024; 97.78% CI, 0.886-1.184). In the low and high dose cohorts, estimated median OS was 15.1 and 15.9 months, respectively (HR, 1.042; 97.78% CI, 0.886-1.224).
Rates of adverse events favored patients in the low dose cohort: lower number of deaths in the last 30 days of the last study (3.8% vs 5.4% in the high dose cohort), less infection-related deaths within a month of treatment initiation (0.7% vs 1.3%), lower grade 3/4 infections (10% vs 20%), and less likelihood of neutropenia (2% vs 9%).
An additional trial (FIRSTANA) further confirmed that a lower dose of cabazitaxel is equally effective and is relatively less toxic in in patients with metastatic castration-resistant prostate cancer.—Zachary Bessette