Enanta Regains Full Rights to NS5A Inhibitor EDP-239 for Hepatitis C Virus from Novartis

WATERTOWN, Mass., October 1, 2014 — Enanta Pharmaceuticals, Inc., (NASDAQ: ENTA) a research and development-focused biotechnology company dedicated to creating small molecule drugs in the infectious disease field, today announced that the company has entered into an agreement to regain full rights from Novartis to EDP-239, an NS5A inhibitor currently in phase 1 development for hepatitis C virus (HCV).

"Novartis notified Enanta that as part of an ongoing portfolio transformation, HCV research would no longer be a strategic focus for Novartis," stated Jay R. Luly, Ph.D., President and CEO. "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."

Enanta and Novartis entered into their strategic collaboration to advance EDP-239 in February 2012. The new agreement provides for the completion or transition to Enanta of specified proof-of-concept clinical studies currently underway involving EDP-239, and a combination study with EDP-239 and Alisporivir, a cyclophilin inhibitor licensed by Novartis from Debiopharm.

Enanta's proprietary HCV portfolio includes EDP-239 in Enanta's NS5A inhibitor program, as well as its cyclophilin inhibitor and nucleotide polymerase inhibitor programs, both of which are in preclinical development.

About EDP-239

EDP-239 is Enanta's lead NS5A inhibitor for HCV infection. NS5A is a non-structural (NS) viral protein that is essential to viral replication of HCV. EDP-239 has demonstrated potent activity against major HCV genotypes when tested in the replicon assay, which is a common in vitro test for determining potency of an active compound in reducing HCV replication. In addition, EDP-239 has additive or synergistic antiviral activity when used in combination with other anti-HCV therapeutics (direct-acting antiviral and host-targeted antiviral) in reducing HCV replication. Enanta's NS5A program and intellectual property estate in the HCV field were derived from its internal drug discovery efforts.

About Enanta

Enanta Pharmaceuticals is a research and development-focused biotechnology company that uses its robust chemistry-driven approach and drug discovery capabilities to create small molecule drugs in the infectious disease field. Enanta is discovering, and in some cases developing, novel inhibitors designed for use against the hepatitis C virus (HCV). These inhibitors include members of the direct-acting antiviral (DAA) inhibitor classes – protease (partnered with AbbVie), NS5A and nucleotide polymerase – as well as a host-targeted antiviral (HTA) inhibitor class targeted against cyclophilin. Additionally, Enanta has created a new class of antibiotics, called Bicyclolides, for the treatment of multi-drug resistant bacteria, with a focus on developing an intravenous and oral treatment for hospital and community MRSA (methicillin-resistant Staphylococcus aureus) infections.

Forward Looking Statements Disclaimer

This press release contains forward-looking statements, including with respect to the prospects for development of EDP-239 and the planned transition of clinical development of EDP-239. Statements that are not historical facts are based on our management's current expectations, estimates, forecasts and projections about our business and the industry in which we operate and our management's beliefs and assumptions. The statements contained in this release are not guarantees of future performance and involve certain risks, uncertainties and assumptions, which are difficult to predict. Therefore, actual outcomes and results may differ materially from what is expressed in such forward-looking statements. Important factors that may affect actual results include results of ongoing clinical trials of EDP-239, the development of other compounds of Enanta or others for use in combination with EDP-239, and the clinical development and commercialization of competitive product candidates for HCV. Enanta cautions investors not to place undue reliance on the forward-looking statements contained in this release. These statements speak only as of the date of this release, and Enanta undertakes no obligation to update or revise these statements, except as may be required by law.