Biweekly cabazitaxel plus G-CSF beneficial to certain older mCRPC patients

In the treatment of older patients with metastatic castration-resistant prostate cancer (mCRPC) who are considered unsuitable candidates for standard cabazitaxel (CBZ) regimens, treatment with CBZ at 16 mg/m² (biweekly CBZ16) plus prophylactic granulocyte colony–stimulating factor (G-CSF) at each cycle helps reduce the risk of higher grade neutropenia and/or neutropenic complications while yielding similar clinical outcomes, according to the results of the phase III CABASTY trial.

CABASTY involved 196 patients aged at least 65 years who had progressive mCRPC. All patients had been treated with docetaxel and at least one novel androgen receptor–targeted agent. These patients were randomly assigned to receive biweekly CBZ16 plus G-CSF and daily prednisolone (experimental group) or triweekly CBZ25 plus G-CSF and daily prednisolone (control group).

Of the patients, 99 were included in the experimental group and 97 in the control group. The median age of the entire cohort was 74.6 years, and 181 (92.3 percent) had an Eastern Cooperative Oncology Group performance status of 0 or 1. The median follow-up duration was 31.3 months.

Relative dose intensities did not significantly differ between the treatment groups (median, 92.7 percent in the control group vs 92.8 percent in the experimental group). Grade 3 or higher neutropenia and/or neutropenic complications occurred with significantly greater frequency in the control group than in the experimental group (62.5 percent vs 5.1 percent; odds ratio, 0.03, 95 percent confidence interval, 0.01–0.08; p<0.001).

Likewise, more patients in the control vs experimental group had grade 3 or higher adverse events (72.9 percent vs 56.1 percent). One patient in the control group died of a neutropenic complication.