Summary Background Ipilimumab is a fully human monoclonal antibody that binds cytotoxic T-lymphocyte antigen 4 to enhance antitumour immunity. Our aim was to assess the use of ipilimumab after ...radiotherapy in patients with metastatic castration-resistant prostate cancer that progressed after docetaxel chemotherapy. Methods We did a multicentre, randomised, double-blind, phase 3 trial in which men with at least one bone metastasis from castration-resistant prostate cancer that had progressed after docetaxel treatment were randomly assigned in a 1:1 ratio to receive bone-directed radiotherapy (8 Gy in one fraction) followed by either ipilimumab 10 mg/kg or placebo every 3 weeks for up to four doses. Non-progressing patients could continue to receive ipilimumab at 10 mg/kg or placebo as maintenance therapy every 3 months until disease progression, unacceptable toxic effect, or death. Patients were randomly assigned to either treatment group via a minimisation algorithm, and stratified by Eastern Cooperative Oncology Group performance status, alkaline phosphatase concentration, haemoglobin concentration, and investigator site. Patients and investigators were masked to treatment allocation. The primary endpoint was overall survival, assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov , number NCT00861614. Findings From May 26, 2009, to Feb 15, 2012, 799 patients were randomly assigned (399 to ipilimumab and 400 to placebo), all of whom were included in the intention-to-treat analysis. Median overall survival was 11·2 months (95% CI 9·5–12·7) with ipilimumab and 10·0 months (8·3–11·0) with placebo (hazard ratio HR 0·85, 0·72–1·00; p=0·053). However, the assessment of the proportional hazards assumption showed that it was violated (p=0·0031). A piecewise hazard model showed that the HR changed over time: the HR for 0–5 months was 1·46 (95% CI 1·10–1·95), for 5–12 months was 0·65 (0·50–0·85), and beyond 12 months was 0·60 (0·43–0·86). The most common grade 3–4 adverse events were immune-related, occurring in 101 (26%) patients in the ipilimumab group and 11 (3%) of patients in the placebo group. The most frequent grade 3–4 adverse events included diarrhoea (64 16% of 393 patients in the ipilimumab group vs seven 2% of 396 in the placebo group), fatigue (40 11% vs 35 9%), anaemia (40 10% vs 43 11%), and colitis (18 5% vs 0). Four (1%) deaths occurred because of toxic effects of the study drug, all in the ipilimumab group. Interpretation Although there was no significant difference between the ipilimumab group and the placebo group in terms of overall survival in the primary analysis, there were signs of activity with the drug that warrant further investigation. Funding Bristol-Myers Squibb.
Summary Background Cabazitaxel is a novel tubulin-binding taxane drug with antitumour activity in docetaxel-resistant cancers. We aimed to compare the efficacy and safety of cabazitaxel plus ...prednisone with those of mitoxantrone plus prednisone in men with metastatic castration-resistant prostate cancer with progressive disease after docetaxel-based treatment. Methods We undertook an open-label randomised phase 3 trial in men with metastatic castration-resistant prostate cancer who had received previous hormone therapy, but whose disease had progressed during or after treatment with a docetaxel-containing regimen. Participants were treated with 10 mg oral prednisone daily, and were randomly assigned to receive either 12 mg/m2 mitoxantrone intravenously over 15–30 min or 25 mg/m2 cabazitaxel intravenously over 1 h every 3 weeks. The random allocation schedule was computer-generated; patients and treating physicians were not masked to treatment allocation, but the study team was masked to the data analysis. The primary endpoint was overall survival. Secondary endpoints included progression-free survival and safety. Analysis was by intention to treat. This study is registered at ClinicalTrials.gov , NCT00417079. Findings 755 men were allocated to treatment groups (377 mitoxantrone, 378 cabazitaxel) and were included in the intention-to-treat analysis. At the cutoff for the final analysis (Sept 25, 2009), median survival was 15·1 months (95% CI 14·1–16·3) in the cabazitaxel group and 12·7 months (11·6–13·7) in the mitoxantrone group. The hazard ratio for death of men treated with cabazitaxel compared with those taking mitoxantrone was 0·70 (95% CI 0·59–0·83, p<0·0001). Median progression-free survival was 2·8 months (95% CI 2·4–3·0) in the cabazitaxel group and 1·4 months (1·4–1·7) in the mitoxantrone group (HR 0·74, 0·64–0·86, p<0·0001). The most common clinically significant grade 3 or higher adverse events were neutropenia (cabazitaxel, 303 82% patients vs mitoxantrone, 215 58%) and diarrhoea (23 6% vs one <1%). 28 (8%) patients in the cabazitaxel group and five (1%) in the mitoxantrone group had febrile neutropenia. Interpretation Treatment with cabazitaxel plus prednisone has important clinical antitumour activity, improving overall survival in patients with metastatic castration-resistant prostate cancer whose disease has progressed during or after docetaxel-based therapy. Funding Sanofi-Aventis.
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