Plexxikon seeks vemurafenib marketing approval from FDA and EMA for melanoma treatment

Plexxikon Inc., a member of the Daiichi Sankyo Group, today announced that applications for market approval for vemurafenib (PLX4032/RG7204) for the treatment of metastatic melanoma have been submitted to the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA). Additionally, a pre-marketing application for approval for a companion diagnostic test has been submitted in the U.S.; the test also will be registered in Europe. Vemurafenib is an oral drug that selectively targets the BRAF ^V600 mutation, which occurs in about half of all cases of melanoma and eight percent of all solid tumors. The companion diagnostic determines whether a patient's tumor tests positive for the BRAF mutation and is eligible to receive vemurafenib treatment.

"We are truly excited to have reached this milestone for vemurafenib, particularly for the melanoma patients who are in desperate need of new treatment options," said K. Peter Hirth, Ph.D., chief executive officer of Plexxikon. "From the discovery of vemurafenib in 2005 to this submittal for marketing approval, a dedicated team has advanced this personalized medicine through development as expeditiously as possible for the benefit of patients. Our partner, Roche, as well as our clinical investigator team and collaborators, have collectively made this a truly rewarding collaboration."

The submissions are based on results from Phase 2 and 3 trials (BRIM2 and BRIM3) that evaluated vemurafenib in patients with BRAF ^V600 mutation-positive melanoma, as determined by the cobas 4800 BRAF ^V600 Mutation Test. Earlier this year, the company reported positive data from an interim analysis of BRIM3 which showed that the study met the pre-specified criteria for co-primary endpoints for BRIM3 for progression-free survival and overall survival, and that the safety profile was generally consistent with the previous vemurafenib studies. Based on these results, the data safety monitoring board for the trial recommended early termination of the trial and allowed dacarbazine-treated patients to immediately cross over to vemurafenib treatment. BRIM2 results reported earlier showed a 52 percent confirmed response rate, with tumor shrinkage in the majority of patients, consistent with results from earlier studies.

The most frequent Grade 3 adverse event observed in clinical trials of vemurafenib was cutaneous squamous cell carcinoma, a common skin cancer treated by local excision (minor surgery done in a physician's office). The most common adverse events were rash, increased sun sensitivity, joint pain, hair loss and fatigue. Possible serious side effects of vemurafenib include liver problems, changes in heartbeat or very fast or abnormal heartbeats, and allergic reactions.