Biweekly Cabazitaxel Regimen Reduces Occurrence of Neutropenia Among Older Patients With Metastatic Castration-Resistant Prostate Cancer

The Phase 3 CABASTY Trial

Biweekly cabazitaxel at 16 mg/m2 plus prophylactic granulocyte colony-stimulating factor (G-CSF) significantly reduced the incidence of grade ≥3 neutropenia and/or neutropenic complications among patients with metastatic castration-resistant prostate cancer compared to triweekly cabazitaxel at 25 mg/m2.

Stéphane Oudard, MD, PhD, European Hospital Georges Pompidou, Paris, France, and coauthors wrote, “Many older patients with metastatic castration-resistant prostate cancer are considered unfit for taxane chemotherapy.”

This trial enrolled 196 patients 65 years or older with progressive metastatic castration-resistant prostate cancer who had previously been treated with docetaxel and at least 1 novel androgen receptor-targeted agent. Patients were randomized on a 1-to-1 basis to receive either 16 mg/m2 cabazitaxel biweekly (n = 99; experimental arm) or 25 mg/m2 cabazitaxel triweekly (n = 97; control arm), plus G-CSF and daily prednisolone. The primary end point was the occurrence of grade ≥3 neutropenia measured at nadir and/or neutropenic complications.

At a median follow-up duration of 31.3 months, the rate of grade ≥3 neutropenia and/or neutropenic complications in the control arm was 62.5%, compared with 5.1% in the experimental arm (odds ratio, 0.03; 95% confidence interval [CI], 0.01 to 0.08; P < .001).

Commenting on these results, Alicia Morgans, MD, MPH, Dana-Farber Cancer Institute at Harvard Medical School, Boston, Massachusetts, wrote, “Importantly, disease control end points of median radiographic progression-free survival (10.25 months vs 7.82 months, P = .89, in the triweekly vs biweekly regimens, respectively) and median overall survival (14.1 months for both arms, P = .39) were similar between groups.” Grade 3 or higher adverse events overall were more common in the control arm vs the experimental arm. Additionally, 1 patient died of a neutropenic complication in the control arm.

Compared with the standard regiment, biweekly 16 mg/m2 cabazitaxel plus G-CSF significantly reduced by 12-fold the occurrence of grade 3 or higher neutropenia and/or neutropenic complications, with comparable clinical outcomes,” wrote Dr Oudard et al. They added, “Biweekly [cabazitaxel at 16 mg/m2) regimen should be offered to patients 65 years or older with [metastatic castration-resistant prostate cancer] for whom the standard regimen is unsuitable.”

Source:

Oudard S, Ratta R, Voog E, et al. Biweekly vs triweekly cabazitaxel in older patients with metastatic castration-resistant prostate cancer: The CABASTY phase 3 randomized clinical trial. JAMA Oncol. Published online October 26, 2023. doi:10.1001/jamaoncol.2023.4255

Morgans A. Expanding treatment options for older adults with prostate cancer. JAMA Oncol. Published online October 26, 2023. doi:10.1001/jamaoncol.2023.4172