Docetaxel and imatinib every 21 days for castration resistant prostate cancer: A phase II trial

摘要: e16086 Background: Docetaxel (D) IV every 21 days, is the only cytotoxic agent that prolongs survival in men with castrate resistant prostate cancer (CRPC). Imatinib (I), a tyrosine kinase inhibitor, modulates PDGFR-ß in tumor vasculature. Based on phase I data from our institution, we hypothesized that D plus I would prolong time to progression (TTP) in patients (pts) with CRPC. Methods: Subjects with CRPC received D 60 mg/m2 IV every 21 days plus I 400 mg PO daily. After 10 pts, the study treatment was modified due to toxicity so that pts received I 400 mg on 10 of 21 days/cycle. The primary endpoint was TTP. Secondary endpoints were rate of PSA response and overall survival (OS). The sample size of 43 pts was designed to provide 90% power to detect an increase in TTP from 5 to 8 months. Results: 43 pts enrolled from 8/05 to 9/08. Age at enrollment ranged from 54–86 years (median 69 years). 14 pts received <1 cycle of D plus I and were unevaluable: 10 had significant toxicity, 4 due to non-treatment related reasons. Primary toxicities were hematologic: 21% G4 neutropenia, 5% G4 anemia, and no G4 thrombocytopenia. Fatigue, nausea, diarrhea, and electrolyte abnormalities were common, but <2 cases each of G3-G4 toxicity occurred. 1 case of G5 non-neutropenic sepsis occurred. 29 pts received >2 cycles of chemotherapy (mean 4.6). 12 pts had PR (41.4%), 9 had SD (31.0%), and 8 had no response (27.6%) by PSA. No objective responses were seen by CT imaging among 10 pts with measurable disease. 3 pts remain on trial. For evaluable pts, overall median TTP was 6.4 months (95% CL: 4.8, 8.4 months) compared with TTP of 5 months seen in previous trials. 23 (79%) pts had PSA progression, 3 pts died before progression, and 3 pts remain on trial. For all evaluable pts who had PR or SD by PSA (N = 21), median TTP was 7.1 months (95% CL: 5.5, 9.1 months). Median OS was 23.1 months (95% CL: 11.61 months, NR), compared with 18.9 months for GC Conclusions: Docetaxel on day 1 plus imatinib 10 days of each 21-day cycle resulted in meaningful improvement in TTP in the subset of pts who showed a response. Toxicity precludes its use in the general population, although its role in select pts with good performance status needs to be explored. [Table: see text]