Pain and Health-related Quality of Life with Biweekly Versus Triweekly Cabazitaxel Schedule in Older Men with Metastatic Castration-resistant Prostate Cancer in the Multicenter, Randomized CABASTY Trial

Background and objective: The CABASTY study showed that more frequent administration of a lower dose of cabazitaxel (CBZ) reduced toxicity in older men with metastatic castration-resistant prostate cancer (mCRPC), without compromising efficacy. Here, we investigated the impact of a biweekly CBZ schedule on patient-reported pain and health-related quality of life (HRQoL).

Methods: We randomized 196 patients from 25 centers (1:1, stratified by age and G8 score) to the biweekly CBZ16 (CBZ 16 mg/m2) experimental arm or the triweekly CBZ25 (CBZ 25 mg/m2) control arm (CABASTY study, NCT02961257). We assessed pain using the Numeric Pain Rating Scale and HRQoL using the Functional Assessment of Cancer Therapy-Prostate (FACT-P) questionnaire.

Key findings and limitations: A total of 141 patients were available for a pain and 160 for an HRQoL analysis. Median time to pain progression (stratified hazard ratio [HR]: 1.7, confidence interval [CI]: 0.67-4.22, p = 0.3) and median time to first opiate use (stratified HR: 1.05, CI: 0.44-2.55, p = 0.9) did not differ between arms. We did not see a significant difference in median time to deterioration of FACT-P total score between treatments (stratified HR: 0.88, CI: 0.47-1.7, p = 0.7). Interestingly, the time to onset of several adverse events was significantly longer in the biweekly CBZ16 group.

Conclusions and clinical implications: HRQoL did not significantly differ between the biweekly CBZ16 and the standard schedule. Additionally, onset of some adverse events was delayed. These results may increase health care providers' confidence in using CBZ in older patients with mCRPC who are denied chemotherapy.

Patient summary: Androgen receptor pathway inhibitors are often preferred to taxane chemotherapy as a treatment of second or subsequent line in older metastatic castration-resistant prostate cancer patients due to more frequent treatment-related toxicities. Here, we showed that quality of life and pain did not differ significantly with an adapted schedule of cabazitaxel (CBZ), compared with the standard regimen. This CBZ schedule could increase eligibility of older patients for chemotherapy.