Dual MEK/AKT inhibition with trametinib and GSK2141795 does not yield clinical benefit in metastatic NRAS-mutant and wild-type melanoma

Abstract

Aberrant MAPK and PI3K pathway signaling may drive the malignant phenotype in NRAS-mutant and BRAF^WT NRAS^WT metastatic melanoma. To target these pathways, NRAS-mutant and BRAF^WT NRAS^WT patients received oral trametinib at 1.5 mg daily and GSK2141795 at 50 mg daily in a two-cohort Simon two-stage design. Participants had adequate end-organ function and no more than two prior treatment regimens. Imaging assessments were performed at 8-week intervals. A total of 10 NRAS-mutant and 10 BRAF^WT NRAS^WT patients were enrolled. No objective responses were noted in either cohort. The median PFS and OS were 2.3 and 4.0 months in the NRAS-mutant cohort and 2.8 and 3.5 months in the wild-type cohort. Grade 3 and grade 4 adverse events, primarily rash, were observed in 25% of patients. We conclude that the combination of trametinib and GSK2141795 does not have significant clinical activity in NRAS-mutant or BRAF^WT NRAS^WT melanoma.

Trial registration: ClinicalTrials.gov NCT01941927.

Keywords: AKT; NRAS; GSK2141795; MEK; melanoma; trametinib; wild type.