EPIX has ongoing preclinical and discovery programs targeting GPCRs and ion channels for the treatment of cardiac arrhythmia, cancer, inflammatory diseases, pain and cystic fibrosis.

In 2006 EPIX entered into a worldwide multi-target strategic collaboration with GlaxoSmithKline (GSK) to discover, develop and market novel medicines targeting four GPCRs for the treatment of a variety of diseases, including EPIX's novel 5-HT4 partial agonist program, PRX-03140, in clinical development for the treatment of Alzheimer's disease. EPIX will be responsible for the discovery and development of small molecule drug candidates targeting four GPCRs, including PRX-03140, through to clinical proof-of-concept, at which point GSK will have an exclusive option to license each product for further development and commercialization on a worldwide basis. If GSK exercises the option to license EPIX's 5-HT4 partial agonist program, EPIX will retain the right to co-promote any products from that program in the United States.

EPIX has an agreement with Amgen for the development of novel, orally available S1P1 modulators for the treatment of multiple auto-immune diseases. EPIX and Amgen are collaborating on the development of existing EPIX preclinical-stage compounds and new S1P1 modulators. Amgen will be responsible for clinical development and commercialization of the product candidate(s).

EPIX also has a collaborative research, development, and commercialization agreement with Cystic Fibrosis Foundation Therapeutics Inc., the drug discovery and development affiliate of the Cystic Fibrosis Foundation, focused on discovering potential drug therapies targeting the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) ion channel.