A phase II study of patupilone in patients (pts) with metastatic castration- resistant prostate cancer (CRPC) who have progressed after docetaxel

Abstract

5139 Background: Chemotherapy for pts with CRPC who have progressed after docetaxel remains to be defined. Patupilone is an epothilone with broad spectrum pre-clinical activity including in taxane resistant models. Methods: Multicenter, 2-stage design. Pts with metastatic CRPC with progressive disease during or within 6 months of receiving docetaxel were eligible. Patupilone was initially given 10mg/m 2 IV every 3 weeks. PSA response rate (≥50% decline) was the primary endpoint (H0 = 15%, H1 = 25%, α = 0.1, β = 0.2). Secondary endpoints were measurable disease response, serial pain and analgesics scores, progression free survival (PFS) and overall survival (OS). Results: 83 pts were enrolled from March 2007-June 2008. 401 cycles administered (median 5, range 1–15). Baseline characteristics (range): median age 67 (47–85), PSA 212 (2.6–11520), hemoglobin 118 (89–160), median time to progression after docetaxel 1.0 months (0.0–6.0), number of prior chemotherapy regimens 1:2:3+ in 45:28:10 pts, ECOG PS 0–1:2 in 73:10 pts, disease in bone/lymph nodes/viscera in 76/47/14 pts respectively. In the first 6 pts, gastrointestinal serious adverse events (AE) occurred in 4 pts (diarrhea and vomiting) which lead to a dose reduction of patupilone to 8 mg/m2 for subsequent patients. Grade 3/4 related adverse events at this dose included fatigue (16%), diarrhea (13%) and anorexia (5%). There were no grade 3/4 hematologic AEs. In 78 pts evaluable for PSA response, PSA declines of ≥30% and ≥50% have occurred in 44/78 (56%) and 35/78 (45%) with a confirmed PSA response in 25 pts (32%). Partial response occurred in 5% and stable disease in 64% of 44 evaluable pts. Pain response (2 point decline on 6 point scale) occurred in 36 (51%) of 71 pts eligible for analysis. Median PFS for PSA and non-PSA outcomes (measurable disease/symptomatic progression or death) was 7.6 months (3.7–11.5) and 5.6 months (3.9–7.3) respectively. Follow up for OS is continuing. Conclusions: Patupilone 8 mg/m2 every 3 weeks was well tolerated and associated with encouraging PFS, PSA and pain responses in pts with docetaxel resistant/refractory disease. Further investigation of patupilone in this population is warranted. [Table: see text]