Epizyme, a clinical-stage biopharmaceutical company creating novel epigenetic therapeutics, has earned a $6 million milestone payment from GlaxoSmithKline (GSK). The milestone payment follows GSK’s initiation of patient dosing in a Phase 1 clinical trial of GSK3326595 (formerly EPZ015938), a first-in-class protein arginine methyltransferase-5 (PRMT5) inhibitor discovered by Epizyme and licensed to GSK. PRMT5 is a protein methyltransferase that is associated with a number of human cancers.

“Epizyme has pioneered the discovery and development of epigenetic therapies for the treatment of cancer, with three agents discovered by Epizyme now in clinical development,” said Robert Bazemore, president and chief executive officer, Epizyme. “Our collaboration with GSK represents an important part of our strategy of partnering with industry leaders to extend the breadth of our epigenetic therapies while providing resources to help us accelerate our portfolio of assets. We look forward to GSK’s continued progress with this program.”

GSK has initiated a Phase 1, dose-escalation study to investigate the safety, pharmacokinetics, pharmacodynamics and clinical activity of GSK3326595 in patients with solid tumors and non-Hodgkin lymphoma.

“The introduction of this PRMT5 inhibitor into the clinic by GSK is an exciting scientific achievement for Epizyme,” said Robert Copeland, president of research and chief scientific officer, Epizyme. “This milestone reinforces the strength of our scientific capabilities, which have enabled us to expand our platform into new epigenetic target classes of potentially high importance in oncology. Through our collaborations with GSK and other biopharmaceutical companies, as well as our in-house research efforts, we have developed a number of novel epigenetic programs that we believe hold tremendous potential, including this first-in-class PRMT5 inhibitor.”