Phase I/II Trial of Tremelimumab in Patients With Metastatic Melanoma.
J Clin Oncol. 2009 Jan 12. [Epub ahead of print]
Camacho LH, Antonia S, Sosman J, Kirkwood JM, Gajewski TF, Redman B, Pavlov D, Bulanhagui C, Bozon VA, Gomez-Navarro J, Ribas A.
University of Texas M.D. Anderson Cancer Center, Houston, TX; H Lee Moffitt Cancer Center & Research Institute, Tampa, FL; Vanderbilt-Ingram Cancer Center, Nashville, TN; University of Pittsburgh School of Medicine, Pittsburgh, PA; University of Chicago, Chicago, IL; University of Michigan Comprehensive Cancer Center, Ann Arbor, MI; Pfizer Global Research & Development, New London, CT; University of California Los Angeles, Los Angeles, CA.
PURPOSE:
Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) blockade with tremelimumab (CP-675,206), a fully human anti-CTLA4 monoclonal antibody, was tolerated and demonstrated antitumor activity in a single dose, dose-escalation phase I trial in patients with solid tumors. This phase I/II trial was conducted to examine safety of multiple doses of tremelimumab, to further assess efficacy, and to identify an appropriate dosing regimen for further development.
PATIENTS AND METHODS:
Twenty-eight patients with metastatic melanoma received monthly intravenous infusions of tremelimumab at 3, 6, or 10 mg/kg for up to 1 year to determine recommended monthly phase II dose. During phase II, 89 patients received tremelimumab 10 mg/kg once every month or 15 mg/kg every 3 months.
RESULTS:
No dose-limiting toxicity was observed in phase I once every month dosing. In phase II, 8 (10%) of 84 response-assessable patients attained objective antitumor responses; best overall objective response was one complete response and three partial responses in each dosing regimen. Most responses were durable (range, 3 to 30+ months). Most frequent treatment-related adverse events (AEs) were diarrhea, rash, and pruritus. Frequency of grade 3/4 AEs was 13% in the 15 mg/kg every 3 months arm and 27% in the 10 mg/kg once every month. Serious AEs were also less frequent in the 15 mg/kg once every 3 months cohort (9% v 23% in 10 mg/kg arm).
CONCLUSION:
Multiple infusions of tremelimumab were generally tolerable and demonstrated single-agent antitumor activity. Both phase II regimens generated durable tumor responses. Based on its more favorable safety profile, 15 mg/kg every 3 months was selected for further clinical testing. |
