Cobimetinib Plus Vemurafenib Associated With Improved PFS for Advanced Melanoma

Exelixis and their partner Roche are seeking Fast Track, US Food and Drug Administration (FDA) approval for their combination therapy drug for people with BRAF V600 mutation-positive advanced melanoma.

A New Drug Application for cobimetinib (MEK inhibitor) in combination with vemurafenib (Zelboraf) showed promising results based on the success of the coBRIM Phase III study. Melanoma patients diagnosed with the V600 mutation in their genes had improved progression-free survival (PFS) with the duo therapy compared to vemurafenib alone.

Vemurafenib is used to treat those patients with BRAF V600 mutation-positive metastatic melanoma, whereas cobimetinib works by “shutting down” the MEK pathway-this pathway helps to regulate growth factor receptors and promotes tumor proliferation.

The phase III combination drug therapy trial helped patients live longer without tumor growth compared to single-agent vemurafenib therapy. Patients treated with the combination had a median PFS of 9.9 months compared to 6.2 months on vemurafenib alone.

The most common adverse events noted in the coBRIM combination trial were diarrhea, nausea, rash, photosensitivity, and lab abnormalities. More serious adverse events noted (grade 3 or higher) were diarrhea, liver function test abnormalities, and elevated CPK levels.

The combination therapy is already under review with the European Medicines Agency  (EMA) and if the FDA accepts the application, the review time may be reduced from 10 months to 6 months-Roche submitted its application to the EMA in September.

References:

FierceBiotech (2014). Roche and Exelixis head to the FDA with their melanoma combo.