Selumetinib: a promising pharmacologic approach for KRAS-mutant advanced non-small-cell lung cancer.

Selumetinib is a potent and selective inhibitor of MEK1 and 2 that is currently being clinically developed for the treatment of several human malignancies. Initially administered as free-base suspension, a more convenient Hyd-sulfate capsule formulation has recently been developed. Phase I studies revealed that acneiform dermatitis was the dose-limiting toxicity of both the free-base and capsule formulation given two-times a day at the maximum tolerated doses of 100 and 75 mg, respectively, with the capsule formulation resulting into a significantly higher drug bioavailability. Importantly, as a MEK inhibitor, selumetinib could be particularly effective in tumors with a hyperactivated Ras/Raf/MEK/ERK pathway, which might be the case of KRAS-mutant non-small-cell lung cancers (NSCLCs). Accordingly, a recent randomized Phase II study evaluating docetaxel plus selumetinib or placebo in KRAS-mutant pretreated advanced NSCLC patients has demonstrated a significant improvement in terms of response rate, progression-free survival and patient-reported outcomes in favor of the combination arm. These positive results support further clinical evaluation of selumetinib in NSCLC, and confirmatory ongoing and future trials will assess its role according to KRAS-mutation status and in combination regimens with other targeted agents.