Vertex’s Collaborator Merck Suspends Patient Enrollment in Clinical Trials of MK-0457 (VX-680) Pending Full Analysis of Clinical Data

Vertex Pharmaceuticals Incorporated (Nasdaq: VRTX) and Merck & Co., Inc. today provided an update to their collaborative Aurora kinase research and development program, which is targeting the treatment of cancer. Merck has suspended enrollment in clinical trials of the lead investigational Aurora kinase inhibitor in the collaboration, MK-0457 (VX-680), pending a full analysis of all efficacy and safety data for MK-0457. The decision was based on preliminary safety data, in which a clinical safety finding of QTc prolongation was observed in one patient. Merck and Vertex have a broad research and development program underway to evaluate Aurora kinase inhibitors as novel approaches to targeted cancer treatment. As part of Merck’s strategy to develop multiple drug candidates in different tumor types and treatment combinations, Merck plans to initiate in early 2008 a Phase 1 trial of VX-689 in patients with advanced and/or refractory solid tumors.

MK-0457 is being investigated in a Phase 2 trial in patients with treatment-refractory chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ALL) containing the T315I mutation, as well as an ongoing Phase 1 clinical trial in patients with advanced leukemias. Patients currently enrolled in these trials may continue to be treated with MK-0457, with additional monitoring for QTc prolongation. A recently initiated Phase 1 trial of MK-0457 in combination with dasatinib in patients with CML or Ph+ALL has also been suspended. In addition, development of the Aurora kinase inhibitor MK-6592 (VX-667) has been discontinued after the compound did not meet pharmacokinetic objectives in a Phase 1 clinical study.