Enanta Pharmaceuticals, a biotechnology company working on the development of small molecule drugs to treat infections, has announced that it is entering into a new licensing agreement with Novartis to recover the full rights of its EDP-239 product, an NS5A inhibitor that is being developed for the treatment of hepatitis C virus (HCV). The two companies had collaborated together on the therapy in 2012.

The strategic partnership between Enanta and Novartis, dating back from February 2012, appears to be coming to an end, with the ongoing specified proof-of-concept clinical studies involving to EDP-239 set to transition back to Enanta. The company will also assume responsibility for a combination study involving EDP-239 and Alisporivir, a cyclophilin inhibitor licensed by Novartis from Debiopharm.

“Novartis notified Enanta that as part of an ongoing portfolio transformation HCV research would no longer be a strategic focus for Novartis” said the president and CEO of the company, Jay R. Luly, Ph.D. “We appreciate Novartis’ contributions to the clinical development of EDP-239 and its ready agreement to return the NS5A program to us. Enanta is now positioned with three wholly-owned HCV programs from which future drug combinations can be explored.”

EDP-239 is an inhibitor of the non-structural viral protein that encourages the replication of HCV, while NS4A has already been proven effective in the treatment of the majority of HCV genotypes during previously conducted phase 1 clinical trials. EDP-239 also features additive or synergistic antiviral activity if administrated in combination with other anti-HCV therapeutics in reducing HCV replication — hence Enanta’s belief that the therapeutic could be well-suited for HCV combination therapies. In addition, the HCV portfolio from Enanta also includes a cyclophilin inhibitor and nucleotide polymerase inhibitor programs, which are currently in preclinical development.