GlaxoSmithKline has linked up with Epizyme in a deal that could be worth over $650 million to the US biotech.

The alliance will see the firm develop small molecule therapeutics targeting histone methyltransferases (HMTs), described as "an important class of epigenetic enzymes", for the treatment of cancer and other diseases. Under the terms of the agreement, Epizyme will receive an upfront fee of $20 million, plus research funding, and is als eligible to receive more than $630 million in total milestone payments if medicines are commercialized for all targets in the collaboration. 

Epizyme, which could also receive up to double-digit royalties, noted that it will be primarily responsible for research up to development candidate selection, and GSK will take the treatments on from there. The Cambridge, Massachusetts-based group said that the HMT family of epigenetic enzymes contains as many as 96 members, "many of which have been associated genetically with cancer and other diseases". 

Robert Gould, chief executive at Epizyme, said the firm's mission is to develop "personalised therapeutics for genetically-defined patients based on our understanding of the driving role played by many HMTs in human disease". He added that the GSK collaboration "validates our unique discovery platform and the targeted approach we bring to HMT therapeutics".