Cabozantinib not superior to mitoxantrone-prednisone for pain relief in mCRPC
Cabozantinib is not better than mitoxantrone-prednisone at relieving pain in patients with metastatic castration-resistant prostate cancer (mCRPC) with symptomatic bone metastasis, a recent study suggests.
Researchers randomly assigned 119 mCRPC patients to receive 60 mg oral cabozantinib once-daily (n=61; median age, 65.0 years) or 12 mg/m2 mitoxantrone every 3 weeks with 5 mg oral prednisone twice-daily (n=58; median age, 66.0 years). Six-week pain response, measured using the Brief Pain Inventory and validated at week 12, was the primary efficacy endpoint.
In the intention-to-treat population, no significant difference in pain response was observed between the cabozantinib and mitoxantrone-prednisone groups (15 percent vs 17 percent; difference, –2 percent; 95 percent CI, –16 to 11; p=0.8). The same trend was obtained when pain scores were considered as continuous variables (difference between the means, 4.6 percent; –7.8 to 17).
However, bone scan response was significantly greater in patients who received cabozantinib (31 percent vs 5.2 percent; difference, 26 percent; 13–39).
There were no significant between-group differences observed in median overall survival (cabozantinib vs mitoxantrone-prednisone: 9.0 vs 7.9 months; stratified hazard ratio [HR], 0.70; 0.44–1.10) and progression-free survival (2.9 vs 2.8 months; stratified HR, 0.74; 0.41–1.34).
All patients experienced at least one adverse event (AE). Grade 3/4 AEs were common in either group: 70 percent for the cabozantinib and 67 percent for the mitoxantrone-prednisone groups. A similar pattern was observed for serious AEs, which were present in 72 percent and 61 percent of patients in the respective groups.