Phase II study of docetaxel re-treatment in docetaxel-pretreated castration-resistant prostate cancer

To determine the activity and tolerability of docetaxel re-treatment after first-line therapy with docetaxel in castration-resistant prostate cancer (CRPC).

Between November 2005 and January 2009, 45 patients initially responding to docetaxel and then experiencing disease progression after a period of biochemical remission of at least 5 months were enrolled in a prospective multicenter study and re-treated with docetaxel. The primary endpoint was the biochemical response (biochemical partial response defined as > 50% prostate-specific antigen [PSA] decline); secondary endpoints were objective response, toxicity, progression-free survival (PFS) and overall survival (OS).

Partial PSA responses were observed in 11 patients (24.5%), 4 (25%) of whom also had an objective response. The treatment was well tolerated, with grade 1-2 neutropenia, thrombocytopenia, vomiting and peripheral neuropathy noted in 18 (40%), 11 (24.5%), 8 (17.8%), and 6 (13.3%) patients, respectively. The most common grade 3 toxicity was neutropenia, which was observed in 8 patients (17.8%). Median PFS was 5 months and median OS was 13 months.

Docetaxel re-treatment preserves anti-tumour activity and is well tolerated in a selected population of pretreated patients with CRPC. Further randomized trials are needed to confirm our preliminary results.