A subset of patients with advanced endometrial cancer experienced durable response to pembrolizumab, according to a study published in the Journal of Clinical Oncology.1

KEYNOTE-028 (ClinicalTrials.gov Identifier: NCT02054806) is a phase 1b basket trial evaluating pembrolizumab in various solid tumor types. This analysis is of the advanced endometrial cancer cohort.

The cohort enrolled 24 patients with PD-L1–positive, relapsed/refractory, locally advanced or metastatic endometrial cancer to receive 10 mg/kg of pembrolizumab every 2 weeks for up to 24 months or until progression or unacceptable toxicity.

The baseline median age was 67 and 70.8% of patients were Caucasian. The majority of patients had endometroid adenocarcinoma (70.8%), followed by adenocarcinoma other (12.5%), high-grade serous carcinoma (8.3%), and carcinosarcoma (4.2%).

The objective response rate was 13% (95% CI, 2.8-33.6), all of which were partial responses experienced by patients with endometroid adenocarcinoma. The median time to partial response was 8.1 weeks, and the duration of response was at least 64 weeks.

Stable disease was achieved by 13% of patients, with a median duration of 24.6 weeks. There were no complete responses.

The median progression-free survival was 1.8 months (95% CI, 1.6-2.7 months) and median overall survival was not reached.

Treatment-related adverse events (TRAEs) occurred in 54.2% of patients during the 76.2 weeks of median follow-up. The most frequent were fatigue, pruritus, pyrexia, and decreased appetite.

Grade 3 TRAEs occurred in 16.7% and included asthenia and back pain; anemia, hyperglycemia, and hyponatremia; chills and pyrexia; diarrhea. There were no grade 4 or 5 events, and no immune-related adverse events were reported.

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According to the authors, the 13% response rate is comparable to that of chemotherapy for this disease. These data “indicate that pembrolizumab shows promise as a treatment for advanced endometrial cancer, a disease for which current treatment options are limited,” wrote the authors.

Reference

  1. Ott PA, Bang YJ, Berton-Rigaud D, et al. Safety and antitumor activity of pembrolizumab in advanced programmed death ligand 1–positive endometrial cancer: results from the KEYNOTE-028 study. J Clin Oncol. 2017 May 10. doi: 10.1200/JCO.2016.72.5952 [Epub ahead of print]