Patients in the control arm of a Phase III study evaluating the Roche/Genentech/Plexxikon metastatic melanoma candidate RG7204 (PLX4032) are being offered the chance to cross over and start receiving the investigational drug. The decision to make the drug available to all trial patients follows the release of interim data from the BRIM3 study, which confirmed that in comparison with dacarbazine therapy, treatment using RG7204 significantly lengthened both overall and progression-free survival times of patients with previously untreated BRAF V600 mutation-positive metastatic melanoma tumors.
Roche’s Genentech says it is now working with health authorities worldwide to expand the recently announced Patient Access Program for RG7204 and include its use as first-line therapy in patients with BRAF V600 mutation-positive metastatic melanoma. Plexxikon, which originally discovered the drug, separately suggests that plans are also on track to file for marketing approval of RG7204 and its companion diagnostic in the U.S. and Europe during 2011.
RG7204 is a small-molecule candidate designed to selectively inhibit the mutated BRAF protein that is expressed in about 50% of metastatic melanoma cases, Roche explains. The BRIM3 study, initiated in 2010, is comparing oral RG7204 therapy with intravenous dacarbazine as first-line therapy in metastatic melanoma patients with tumors expressing the V600 BRAF mutation. The mutation status of candidate patients is being assessed using Roche Molecular Diagnostics’ cobas® 4800 BRAF V600 Mutation Test, which is being developed in partnership with Plexxikon as a companion diagnostic alongside RG7204.
"PLX4032, first tested in patients in 2006, demonstrates the potential to accelerate development when appropriate patients can be selected with a diagnostic and treated with a targeted medicine," comments K. Peter Hirth, Ph.D., Plexxikon CEO.
Roche and Plexxikon originally signed their license and collaboration agreement for RG7204 in 2006. At the start of 2011 Plexxicon inked a deal with Genentech to co-promote the drug (which it has designated PLX4032) in the U.S., and says it will build its commercial organization and sales force during 2011. The firm says the V600 BRAF mutation is also found in about 10% of colorectal cancers and about 8% of all solid tumors.