Plexxikon Inc. announces that enrollment has been initiated and the first patient has been treated in the first of two pivotal trials of PLX4032 (RG7204) in patients with metastatic melanoma. PLX4032 is a novel, oral and highly selective drug that targets the BRAFV600E cancer-causing mutation occurring in about 50 percent of melanomas and about eight percent of all solid tumors. This single arm Phase 2 B-Raf Inhibitor in Melanoma (BRIM2) trial for previously-treated metastatic melanoma patients, along with a randomized, controlled Phase 3 trial (BRIM3) expected to start by the end of 2009 in first-line patients, are part of the planned registration program for PLX4032. The initiation of the Phase 2 trial has triggered a significant milestone payment to Plexxikon from Roche. Plexxikon is entitled to receive additional payments for milestone achievements as well as royalties on sales of PLX4032. Plexxikon and Roche are co-developing PLX4032 under their 2006 license and collaboration agreement.
The Phase 2 trial (Study #NP22657) is an open label, single arm study in which approximately 100 metastatic melanoma patients who test positive for the BRAFV600E cancer-causing mutation will be treated with PLX4032 at a dose of 960 mg twice-daily (BID). Eligible patients for this trial must have progressed after at least one prior treatment. Patients will be monitored throughout the study for safety and efficacy endpoints. The primary endpoint of this trial is Best Overall Response Rate (BORR) as indicated by tumor regression measured by RECIST (Response Evaluation Criteria in Solid Tumors) criteria. Secondary endpoints include progression-free survival (PFS), symptom improvement and overall survival.
The Phase 2 trial will be conducted at 13 sites in the United States and Australia, and enrollment is expected to be complete by the end of 2009. Patients interested in enrolling in the Phase 2 trial may find additional information at the Roche Clinical Trials Registry (http://www.roche-trials.com/), by visiting www.clinicaltrials.gov, or by contacting the Roche Call Center at 973-235-5000. Roche is conducting all future clinical trials of PLX4032, including these Phase 2 and 3 clinical trials.
Plexxikon has conducted the Phase 1 dose escalation study, and has completed an extension study in exclusively mutation-positive metastatic melanoma patients. Enrollment for a second extension study of mutation-positive colorectal cancer patients is expected to complete by year end.