Vertex Pharmaceuticals said Merck & Co halted enrollment on trials of their investigational leukemia drug MK-0457 due to a potential heart safety issue in one patient.
Vertex and Merck said they suspended trials involving MK-0457, also known as VX-680, pending a full analysis of efficacy and safety data after preliminary data showed that one patient experienced QTc prolongation.
QTc prolongation is a disorder of the heart's electrical system that can result in an irregular heartbeat and is associated with increased risk of sudden cardiac death.
MK-0457 is the lead Aurora kinase inhibitor drug from the companies' development collaboration.
The drug is being studied in a Phase 2 trial in patients with treatment-resistant chronic myelogenous leukemia, or Philadelphia chromosome-positive acute lymphoblastic leukemia.
The companies also suspended a newly launched Phase 1 trial of MK-0457 in combination with dasatinib in those same patient groups.
MK-0457 is also being studied in an ongoing Phase 1 trial in patients with advanced leukemias.
Vertex and Merck said patients currently enrolled in trials may continue to be treated with MK-0457, with additional monitoring for QTc prolongation.
The companies also said they discontinued development of their Aurora kinase inhibitor MK-6592, or VX-667, after the investigational drug failed to meet pharmacokinetic objectives in a Phase 1 trial.