A phase II evaluation of selumetinib (AZD6244, ARRY-142886), a selective MEK-1/2 inhibitor in the treatment of recurrent or persistent endometrial cancer: an NRG Oncology/Gynecologic Oncology Group study.

Background: Activation of the mitogen activated protein kinase pathway plays a pivotal role in cell proliferation and is frequently activated in endometrial cancer. We sought to evaluate the efficacy/safety of selumetinib, a selective MEK-1/2 inhibitor in women with recurrent endometrial cancer.

Methods: This was a phase II, single-arm, open-label study evaluating response and 6-month event-free survival (EFS) as primary endpoints. Eligible patients had measurable disease, 1-2 prior cytotoxic regimens, and performance status 0-2. Selumetinib 75mg PO BID was administered daily until progression or intolerance. One cycle was 28days.

Results: Fifty-four patients were enrolled; 2 were excluded due to improper pre-study treatment (1) and never treated (1), leaving 52 evaluable for efficacy/safety. Median age was 62; histology included endometrioid (58%), serous (17%) and mixed (23%). Seventeen patients (33%) had 2 prior cytotoxic regimens. The median number of cycles administered was 2 (1-34). Three (6%) patients had objective response (1 CR, 2 PR); 13 had SD as best response. The proportion of patients with 6-month EFS was 12%. Median EFS, progression-free and overall survival was 2.1, 2.3, and 8.5months, respectively. Drug-attributed grade 3/4 adverse events were observed (≥5%) were fatigue (15%), anemia (10%), pain (10%), extremity edema (8%), and dyspnea (6%). There was 1 grade 4 infection (renal), 1 grade 4 anemia, and 1 death due to hemorrhage (rectum).

Conclusions: Selumetinib was tolerable in this population but did not meet pre-trial specifications for clinical efficacy.