Margaret A. Marshall

Phase III Randomized Clinical Trial Comparing Tremelimumab With Standard-of-Care Chemotherapy in Patients With Advanced Melanoma

PURPOSE In phase I/II trials, the cytotoxic T lymphocyte-associated antigen-4-blocking monoclonal antibody tremelimumab induced durable responses in a subset of patients with advanced melanoma. This phase III study evaluated overall survival (OS) and other safety and efficacy end points in patients with advanced melanoma treated with tremelimumab or standard-of-care chemotherapy. PATIENTS AND METHODS Patients with treatment-naive, unresectable stage IIIc or IV melanoma were randomly assigned at a ratio of one to one to tremelimumab (15 mg/kg once every 90 days) or physicians choice of standard-of-care chemotherapy (temozolomide or dacarbazine). RESULTS In all, 655 patients were enrolled and randomly assigned. The test statistic crossed the prespecified futility boundary at second interim analysis after 340 deaths, but survival follow-up continued. At final analysis with 534 events, median OS by intent to treat was 12.6 months (95% CI, 10.8 to 14.3) for tremelimumab and 10.7 months (95% CI, 9.36 to 11.96) for chemotherapy (hazard ratio, 0.88; P = .127). Objective response rates were similar in the two arms: 10.7% in the tremelimumab arm and 9.8% in the chemotherapy arm. However, response duration (measured from date of random assignment) was significantly longer after tremelimumab (35.8 v 13.7 months; P = .0011). Diarrhea, pruritus, and rash were the most common treatment-related adverse events in the tremelimumab arm; 7.4% had endocrine toxicities. Seven deaths in the tremelimumab arm and one in the chemotherapy arm were considered treatment related by either investigators or sponsor. CONCLUSION This study failed to demonstrate a statistically significant survival advantage of treatment with tremelimumab over standard-of-care chemotherapy in first-line treatment of patients with metastatic melanoma.

Phase II trial of tremelimumab (CP-675,206) in patients with advanced refractory or relapsed melanoma

Purpose: This phase II study assessed the antitumor activity of tremelimumab, a fully human, anti–CTL-associated antigen 4 monoclonal antibody, in patients with melanoma. Experimental Design: Patients with refractory/relapsed melanoma received 15 mg/kg tremelimumab every 90 days. After 4 doses, patients with tumor response or stable disease were eligible to receive ≤4 additional doses. Primary endpoint was best overall tumor response assessed by an independent endpoint review committee, and secondary endpoints included duration of response, overall survival, progression-free survival, and safety. Results: Of 251 patients enrolled, 246 (241 response-evaluable) received tremelimumab. Objective response rate was 6.6% (16 partial responses); duration of response was 8.9 to 29.8 months. Eight (50%) objective responses occurred in patients with stage IV M1c disease, and 11 (69%) were ongoing at last tumor assessment. Eight (3.3%) patients achieved responses in target lesions (Response Evaluation Criteria in Solid Tumors) despite progressive disease within the first cycle. All 8 survived for >20 months; 5 (63%) remained alive. Clinical benefit rate (overall response + stable disease) was 21% (16 partial responses and 35 stable disease), and median overall survival was 10.0 months. Progression-free survival at 6 months was 15%, and survival was 40.3% at 12 months and 22% at 24 months. Common treatment-related adverse events were generally mild to moderate, and grade 3/4 adverse events included diarrhea (n = 28, 11%), fatigue (n = 6, 2%), and colitis (n = 9, 4%). There were 2 (0.8%) treatment-related deaths. Conclusions: Tremelimumab showed an objective response rate of 6.6%, with all responses being durable ≥170 days since enrollment, suggesting a potential role for tremelimumab in melanoma. Clin Cancer Res; 16(3); 1042–8

Safety profile and pharmacokinetic analyses of the anti-CTLA4 antibody tremelimumab administered as a one hour infusion

BackgroundCTLA4 blocking monoclonal antibodies provide a low frequency but durable tumor responses in patients with metastatic melanoma, which led to the regulatory approval of ipilimumab based on two randomized clinical trials with overall survival advantage. The similarly fully human anti-CTLA4 antibody tremelimumab had been developed in the clinic at a fixed rate infusion, resulting in very prolonged infusion times. A new formulation of tremelimumab allowed testing a shorter infusion time.MethodsA phase 1 multi-center study to establish the safety and tolerability of administering tremelimumab as a 1-hour infusion to patients with metastatic melanoma. Secondary endpoints included pharmacokinetic and clinical effects of tremelimumab.ResultsNo grade 3 or greater infusion-related adverse events or other adverse events preventing the administration of the full tremelimumab dose were noted in 44 treated patients. The overall side effect profile was consistent with prior experiences with anti-CTLA4 antibodies. Objective tumor responses were noted in 11% of evaluable patients with metastatic melanoma, which is also consistent with the prior experience with CTLA4 antagonistic antibodies.ConclusionsThis study did not identify any safety concerns when tremelimumab was administered as a 1-hour infusion. These data support further clinical testing of the 1-hour infusion of tremelimumab. (Clinical trial registration number NCT00585000).

Population pharmacokinetic and pharmacodynamic analysis of tremelimumab in patients with metastatic melanoma

Tremelimumab, a fully human monoclonal antibody specific for human cytotoxic T‐lymphocyte‐associated antigen 4, has been studied in clinical trials. We have reported the results of population pharmacokinetics for tremelimumab in 654 metastatic melanoma patients. Population estimates (inter‐individual variability [IIV]) for pharmacokinetic parameters in a final model were clearance (CL), 0.26 L/day (31.8%) and central volume of distribution, 3.97 L (20.4%). CL was faster in males, patients with higher values of creatinine clearance and endogenous immunoglobulin, and patients with relatively poor baseline prognostic factors. No dose adjustment was needed based on the magnitude of the change of CL (<30%). The association of CL and overall survival (OS) was investigated. In a Phase 3 trial evaluating tremelimumab as first‐line‐treatment, median OS for the 147 patients in the fast‐CL group (≥median CL value) was 9.6 months versus 15.8 months for the 146 patients in the slow‐CL group (