Array BioPharma announced the submission of a New Drug Application (NDA) for binimetinib in patients with advanced NRAS-mutant melanoma to the US Food and Drug Administration (FDA). The submission is based on results of the pivotal phase 3 NEMO (NRAS MELANOMA AND MEK INHBITOR) study, which found binimetinib significantly extended median progression-free survival (PFS), the study's primary endpoint, as compared with dacarbazine.

"The new drug application for binimetinib represents Array's first – an important milestone for this promising compound and our company," said Ron Squarer, chief executive officer, Array BioPharma. "NRAS-mutant melanoma represents an often overlooked subset of advanced disease without meaningful treatment options beyond immunotherapy and NEMO is the first-ever trial to meet a PFS endpoint in this population. We look forward to working with the FDA as they evaluate our application and the potential for binimetinib as a treatment option for these patients."

In the NEMO study, binimetinib significantly extended median PFS at 2.8 months, as compared with 1.5 months observed with dacarbazine [hazard ratio (HR)=0.62 (95% CI 0.47-0.80), p<0.001] in patients with advanced NRAS-mutant melanoma. In the pre-specified subset of patients who received prior treatment with immunotherapy, including ipilimumab, nivolumab or pembrolizumab, patients who received binimetinib experienced 5.5 months of median PFS (95% CI, 2.8–7.6), compared with 1.6 months for those receiving treatment with dacarbazine (95% CI, 1.5–2.8).

Mr. Squarer added, "While the results in the pre-specified sub-group of patients who had received prior treatment with immunotherapy are of interest, interpretation beyond overall consistency with the primary result should be made with care. Array anticipates that the primary consideration for marketing approval will be the results for the primary endpoint of the trial."

In addition to improving PFS, binimetinib also demonstrated significant improvement in overall response rate (ORR) and disease control rate (DCR). While there was no statistically significant difference demonstrated in overall survival, the median overall survival (mOS) favored the binimetinib arm.

Confirmed ORR was 15 percent (95% CI, 11-20 percent) in patients receiving binimetinib vs. 7 percent (95% CI, 3-13 percent) in patients receiving dacarbazine. DCR for patients receiving binimetinib was 58 percent (95% CI, 52-64 percent) vs. 25 percent (95% CI, 18-33 percent) for patients receiving dacarbazine. mOS was estimated at 11.0 months in patients receiving binimetinib vs. 10.1 months for patients treated with dacarbazine [(HR) = 1.0 (95% CI 0.75-1.33), p=0.499].

Under the NEMO protocol, and in accordance with accepted statistical practice, the subgroup analyses of OS are formally conducted only if the key secondary endpoint of OS reached statistical significance.

Binimetinib was generally well-tolerated and the adverse events (AEs) reported were consistent with previous results in NRAS-mutant melanoma patients. Grade 3/4 AEs reported in greater than or equal to 5 percent of patients receiving binimetinib included increased creatine phosphokinase (CPK) and hypertension.

The NEMO results were presented at the 2016 American Society of Clinical Oncology (ASCO) Annual Congress earlier in June.

The NEMO trial, (NCT01763164), is an international, randomized phase 3 study evaluating the safety and efficacy of 45 mg BID binimetinib, compared to 1,000 mg/m2 dacarbazine dosed every three weeks. Prior immunotherapy treatment was allowed.

The primary endpoint of the study is PFS, and secondary endpoints include overall survival (OS), ORR and DCR. Patients underwent radiographic assessment of disease status every six weeks, and assessment of progression was determined by blinded central review. Over 100 sites across North America, Europe, South America, Asia and Australia participated in the study.

Melanoma is the fifth most common cancer among men and the seventh most common cancer among women in the United States, with more than 76,000 new cases and nearly 10,000 deaths from the disease projected in 2016. Activating NRAS mutations are present in up to 20 percent of patients with metastatic melanoma, and is a poor prognostic indicator for these patients. Treatment options for this population remain limited beyond immunotherapy, and patients face poor clinical outcomes and high mortality.

MEK and BRAF are key protein kinases in the MAPK signaling pathway (RAS-RAF-MEK-ERK). Research has shown this pathway regulates several key cellular activities including proliferation, differentiation, survival and angiogenesis. Inappropriate activation of proteins in this pathway has been shown to occur in many cancers, such as melanoma, non-small cell lung, colorectal and thyroid cancers. Binimetinib is a late-stage small molecule MEK inhibitor, which targets key enzymes in this pathway.

Binimetinib is currently being studied in phase 3 trials in advanced cancer patients, including the COLUMBUS trial studying encorafenib in combination with binimetinib in patients with BRAF-mutant melanoma and the recently initiated BEACON trial that will study encorafenib in combination with binimetinib and cetuximab in patients with BRAF V600E-mutant colorectal cancer. Array projects COLUMBUS top-line results availability during the third quarter of 2016.