CHICAGO–Pembrolizumab plus low-dose ipilimumab combination therapy was considered to have an acceptable safety profile in patients with advanced melanoma or renal cell carcinoma during an initial safety run-in period, a study presented at the 2015 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, IL, has shown.

Researchers conducted an assessment of the safety and tolerability of pembrolizumab 2 mg/kg plus low-dose ipilimumab 1 mg/kg every 3 weeks for four doses, followed by pembrolizumab 2 mg/kg every 3 weeks for up to 2 years, among participants of the ongoing phase I/II KEYNOTE-029.

Twenty-two patients were enrolled, of which 12 had melanoma and 10 had renal cell carcinoma.

Results showed that dose-limiting toxicities occurred in six of 19 evaluable patients.

“All dose-limiting toxicities were of grade 3 severity except for one episode of grade 4 lipase elevation,” said Michael B. Atkins, MD, lead author and Deputy Director of the Georgetown Comprehensive Cancer Center in Washington, DC.

Specifically, dose-limiting toxicities included ALT/AST elevation, colitis, uveitis, elevation of pancreatic enzymes, hyperthyroidism, lipase elevation, and pneumonitis. Two patients experienced two dose-limiting toxicities each.

“All dose-limiting toxicities had resolved except for elevated lipase, which was ongoing at the time of data cutoff,” Dr. Atkins said.

Assessment of antitumor activity is ongoing with 14 patients remaining on pembrolizumab at the time of data cutoff.

Due to the positive findings, researchers have initiated a protocol-specified, single-arm expansion cohort to further assess the safety, tolerability, and efficacy of pembrolizumab plus low-dose ipilimumab in patients with advanced melanoma.

Reference

1. Atkins MB, Choueiri TK, Hodi FS, et al. Pembrolizumab (MK-3475) plus low-dose ipilimumab (IPI) in patients (pts) with advanced melanoma (MEL) or renal cell carcinoma (RCC): Data from the KEYNOTE-029 phase 1 study. J Clin Oncol. 2015:33(suppl; abstr 3009).

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