Promising data from Array BioPharma’s MEK162 Phase 2 trial on BRAF and NRAS mutant melanoma

Array BioPharmaJun 5 2012

Promising data on MEK162 in an ongoing Phase 2 trial of patients with BRAF and NRAS mutated advanced melanoma was presented today at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois. MEK162, a small molecule selective inhibitor of the kinases MEK1 and MEK2, showed clinical activity and good tolerability in this patient population. This is the first targeted therapy to show activity in patients with NRAS mutated melanoma.    

Array BioPharma Inc. (NASDAQ: ARRY) invented MEK162 and licensed worldwide rights to develop and commercialize MEK162 to Novartis in April 2010. The ongoing Phase 2 open-label trial is being conducted by Novartis and continues to enroll patients.

Since February 2012, the study has shown that, of the 35 patients with BRAF mutations evaluable for response, eight had partial responses, including two confirmed partial responses and 13 patients demonstrated stable disease. The disease control rate was 60 percent among these patients with at least two scans. Of the 28 patients with NRAS mutations who were evaluable for response, six had partial responses, including three confirmed partial responses and 13 patients demonstrated stable disease. The disease control rate was 68 percent among these patients with at least two scans. The median progression-free survival was 3.55 months [95% CI 2.00 - 3.81 months] for patients with BRAF mutation and 3.65 months [95% CI 2.53 - 5.39 months] for patients with NRAS mutations.

Common adverse events of all grades were consistent with data reported for the MEK inhibitor class and included rash, diarrhea, acneiform dermatitis, edema, creatine phosphokinase elevation, central serous retinopathy-like events, nausea, and fatigue.

"Significant treatment progress has been achieved for patients with advanced melanoma, particularly those with BRAF mutations, over the past few years," said Paolo A. Ascierto, MD, Director of the Unit of Medical Oncology and Innovative Therapy, National Tumor Institute Fondazione G. Pascale. "However, for patients with NRAS mutations, no targeted treatment has been available and prognosis is poor. MEK162 has shown for the first time efficacy in the NRAS mutated melanoma population. This is another important brick in the wall we are building to stop melanoma."

In conclusion, MEK162, the first targeted therapy to show activity in patients with NRAS mutant melanoma, showed clinical activity and good tolerability in patients with BRAF and NRAS mutated advanced melanoma. Novartis is evaluating the development options of MEK162 in melanoma.