On September 17, 2019, the FDA accelerated the approval of a new combination of pembrolizumab (Keytruda; Merck) plus lenvatinib (Lenvima; Eisai) for patients with advanced endometrial carcinoma that is not associated with microsatellite instability high (MSI-H) or mismatch repair–deficient (dMMR) tumors in patients whose disease progressed after systemic therapy and who are candidates for curative surgery or radiation. The FDA granted this application priority review and a breakthrough therapy designation.
The approval of this combination was based on Study 111/KEYNOTE146, a single-arm, multicenter, open-label, multicohort clinical trial of 108 patients with metastatic endometrial carcinoma that had progressed after ≥1 systemic therapies. Patients received oral lenvatinib 20 mg daily plus intravenous pembrolizumab 200 mg every 3 weeks, until disease progression or unacceptable toxicity.
Of the 108 patients, 94 had non–MSI-H or non-dMMR tumors, 11 patients had MSI-H or dMMR tumors, and 3 patients had unknown MSI-H or dMMR status. Efficacy was measured by objective response rate (ORR) and duration of response.
In the 94 patients without MSI-H or dMMR tumors, the ORR was 38.3% (95% confidence interval, 29%-49%), including 10 (10.6%) complete responses and 26 (27.7%) partial responses. The median duration of response was not reached at the time of data cutoff, and 25 (69%) responders had responses lasting ≥6 months.
Side effects with this combination were similar to those previously seen with each treatment.