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.

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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.


  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).