Genentech’s Investigational Combination of Cobimetinib Plus Zelboraf Provided Significant Benefit to People With Advanced Melanoma Over Zelboraf Alone

Genentech has announced positive data from the coBRIM Phase III study. The results showed that people with previously untreated BRAF V600 mutation-positive advanced melanoma who received the MEK inhibitor cobimetinib plus Zelboraf (vemurafenib) lived significantly longer without their disease worsening or death (progression-free survival; PFS) compared with Zelboraf alone. 

The combined therapy reduced the risk of disease worsening or death by half (hazard ratio [HR]=0.51, 95 percent confidence interval [CI] 0.39-0.68; p<0.0001), with a median PFS of 9.9 months for cobimetinib plus Zelboraf compared with 6.2 months with Zelboraf alone. The safety profile was consistent with a previous study of the combination. The most common adverse events seen in the combination arm included diarrhea, nausea, rash, photosensitivity and lab abnormalities.

“We combined cobimetinib and Zelboraf in this study to better inhibit a major cancer growth pathway and hopefully improve clinical outcomes,” said Sandra Horning, MD, Chief Medical Officer and head of Global Product Development. “The coBRIM results are exciting because they support the potential of the combination as a new treatment option for people with BRAF mutation-positive advanced melanoma.”

The coBRIM results were statistically significant across multiple secondary endpoints. The median PFS by independent review committee (IRC) was 11.3 months for the combination arm compared to 6.0 months for the control arm (HR=0.60, 95 percent CI 0.45-0.79; p=0.0003). The objective response rate (ORR) was higher in the combination compared to the control arm (68 vs. 45 percent; p<0.0001). Overall survival (OS) data are not yet mature.

Roche has submitted the coBRIM data to the European Medicines Agency, and Genentech plans to submit a New Drug Application to the US FDA later this year.