In mCRPC patients (pts) previously treated with docetaxel (DOC) and the alternative androgen-targeted agent (ART), cabazitaxel 25 mg/m2 every 3 weeks (CBZ q3w) + G-CSF increases overall survival (OS) compared to abiraterone or enzalutamide. For elderly patients who were unsuited to get CBZ q3w, CBZ 16 mg/m2 every two weeks (CBZ q2w) may be helpful since it causes less severe neutropenia.

Patients with progressive mCRPC (≥65 yrs, ECOG 0-2, G8 >14 or ≤14 with reversible geriatric impairment) who had previously had DOC were randomized to receive CBZ q3w With prednisone (P) + G-CSF vs. CBZ q2w + P + G-CSF, stratified by age (<70 vs. ≥70 years) and G8 (>14 vs ≤14). The percentage of patients with grade ≥3 neutropenia and/or neutropenic consequences was the primary objective (febrile neutropenia, neutropenic infection, sepsis). Radiographic progression-free survival (rPFS), objective tumor response, skeletal-related events (SREs), PSA response, quality of life (not reported here), safety, and OS were considered secondary goals.

In all, 196 patients were randomized (CBZ q3w, n=97; CBZ q2w, n=99; median age, 74.0 yrs; ≥70 years, 79.6%; G8 <14, 19.9%; vulnerable or frail per SIOG guidelines, 30.1%; previous ART, 86.7%). CBZ 3qw and CBZ 2qw both had equivalent relative dosage intensities (92.3% and 91.6%, respectively). With CBZ q3w compared to CBZ q2w, the rate of Grade ≥3 neutropenia and/or neutropenic consequences was noticeably greater (62.9% vs 5.1%; odds ratio = 0.03 [95% CI 29.5-48.9], P<0.001). With CBZ 3qw, grade ≥3 adverse events were more frequent (72.9% vs 58.2%). Neutropenic complications claimed the life of one patient (CBZ q3w arm). No brand-new warning sign was noticed.

CBZ q2w + G-CSF significantly decreased the incidence of grade ≥3 neutropenia and/or neutropenic sequelae with equivalent clinical outcomes when compared to the usual regimen. The CBZ q2w regimen for senior mCRPC patients may revolutionize medical treatment.