Objective: Vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR) correlate with poor prognosis in castration-resistant prostate cancer (CRPC). Sunitinib has shown activity in CRPC and at the time of this analysis there was no standard therapy for docetaxel-refractory CRPC.
Methods: We present a case series data collection of 19 patients with a median age of 73 years, CRPC and rising prostate-specific antigen (PSA). Patients received sunitinib 37.5 mg continuous daily dose. One cycle comprised a 4-week period. Patients were evaluated by CT scan every 8 weeks and PSA was monitored every 4 weeks.
Results: Median Eastern Cooperative Oncology Group (ECOG) performance status score was 2. Patients received a median of two previous treatment lines for the hormone-refractory setting. Baseline median PSA was 280 ng/ml. Patients received a median of 16 weeks of therapy (4 - 48+). One patient achieved a partial response (5%) and 12 (66.7%) achieved stable disease for at least 3 months according to RECIST criteria. Median progression-free survival was 4 months. PSA declined > 50% in 5/19 (26.3%) and stabilized in 7/19 (37%) patients. Frequent adverse events were grade 3 asthenia (21%), grade 3 diarrhea (10%) and grade 3 hand-foot syndrome (15.7%).
Conclusions: Activity with sunitinib was observed in highly pretreated docetaxel-refractory CRPC with acceptable tolerability. Additional studies should confirm the role of antiangiogenic agents in this setting.