As reported in JAMA Oncology by Kristeleit et al, the UK-based phase II PEACOCC trial has shown the benefit of pembrolizumab in previously treated patients with advanced clear cell gynecological cancers (CCGCs).
As stated by the investigators, “Advanced CCGCs have a poor prognosis, with response rates to second-line chemotherapy less than 8%. Preliminary clinical activity with PD-1 inhibitors reported in CCGC merits further investigation.”
Rebecca Kristeleit, MD, PhD
Study Details
In the multicenter trial, 48 eligible patients were treated with pembrolizumab at 200 mg every 21 days for up to 2 years or until disease progression, discontinuation due to toxic effects, or patient/clinician decision. Patients who received 35 cycles of pembrolizumab were eligible for retreatment at disease progression. Overall, 85% of patients had ovarian, 13% endometrial, and 2% had cervical advanced CCGC. The median number of courses of prior therapy was three (range = 1–6). A total of 45 patients (98%) had mismatch repair (MMR)-proficient tumors. The primary endpoint of the trial was progression-free survival at 12 weeks, with the objective of achieving a rate of progression-free survival ≥ 33% and excluding a rate of progression-free survival < 15%.
Key Findings
The 12-week progression-free survival rate was 42% (95% confidence interval [CI] = 28%–57%).
Objective responses (all partial) were observed in 12 patients (25%, 95% CI = 14%–40%). Median duration of response was 13.1 months (95% CI = 4.2–26.5 months). An additional 33% of patients had stable disease.
After a median follow-up of 46.9 months, median progression-free survival was 2.7 months (95% CI = 1.3–5.4 months) and median overall survival was 14.8 months (95% CI = 6.7–28.2 months).
Grade 3 treatment-related adverse events were observed in nine patients (19%), most commonly increased alanine aminotransferase and hyperthyroidism in two patients each (4%). No treatment-related grade 4 adverse events or fatalities were observed.
The investigators concluded, “The PEACOCC trial showed clinical benefit with pembrolizumab in patients with previously treated advanced CCGC, of whom all except one had MMR-proficient disease. Clinical outcomes were durable with an overall tolerable safety profile, justifying further evaluation of pembrolizumab monotherapy for advanced CCGC in a randomized clinical trial.”
Dr. Kristeleit, of Guy’s and St Thomas’ NHS Foundation Trust and Comprehensive Cancer Centre, King’s College London, is the corresponding author for the JAMA Oncology article.
Disclosure: The study was funded by Merck Sharp & Dohme. For full disclosures of the study authors, visit jamanetwork.com.
