Enanta Pharmaceuticals Announces That AbbVie Has Initiated Enrollment of Six Global Phase 3 Clinical Studies of Its Once-Daily, Pan-Genotypic Hepatitis C Treatment

Enanta Pharmaceuticals, Inc., (NASDAQ:ENTA) a research and development-focused biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, today announced the initiation by AbbVie of six global phase 3 clinical studies evaluating the safety and efficacy of an all-oral, once-daily, ribavirin-free, investigational hepatitis C virus (HCV)treatment consisting of a co-formulated combination of ABT-493, an NS3/4A protease inhibitor, and ABT-530, an NS5A inhibitor, in patients with genotypes 1-6 (GT1-6) chronic HCV infection.

ABT-493 is Enanta’s next-generation protease inhibitor being developed by AbbVie and is one of the two direct-acting antivirals in the combination treatment being investigated in the phase 3 studies.

The ENDURANCE and EXPEDITION studies are part of AbbVie’s Phase 3 HCV pipeline program and will recruit approximately 1,600 patients globally, from over 250 study sites in 27 countries. The primary efficacy endpoint of all six studies is the rate of sustained virologic response at 12 weeks post-treatment (SVR₁₂).

The four ENDURANCE studies evaluate AbbVie’s investigational regimen in patients without cirrhosis for up to 12 weeks. ENDURANCE-1 compares SVR in GT1 chronic HCV infected patients who received ABT-493/ABT-530 treatment durations of 12 weeks and as short as eight weeks. ENDURANCE-2 evaluates AbbVie’s investigational regimen versus placebo in GT2 chronic HCV infected patients. ENDURANCE-3 compares AbbVie’s investigational regimen with sofosbuvir/daclatasvir in treatment-naïve patients with GT3 chronic HCV infection. ENDURANCE-4 evaluates GT4-6 chronic HCV infected patients.

The EXPEDITION trials evaluate AbbVie’s investigational regimen for 12 weeks in difficult to treat patient populations with chronic HCV infection. EXPEDITION-1 evaluates AbbVie’s investigational regimen in GT1, 2, 4-6 chronic HCV infected patients with compensated cirrhosis (Child-Pugh A). EXPEDITION-4 evaluates GT1-6 chronic HCV infected patients with severe renal impairment and end-stage renal disease, with or without compensated cirrhosis.

More information on AbbVie’s studies is available at www.clinicaltrials.gov (NCT02604017, NCT02640482, NCT02640157, NCT02636595, NCT02642432, NCT02651194).

About AbbVie's HCV Clinical Development Program for ABT-493 and ABT-530

AbbVie's HCV clinical development program is intended to advance scientific knowledge and the clinical care of people with chronic HCV infection by investigating pan-genotypic (genotypes 1-6), all-oral, ribavirin-free, once-daily treatment for 12 weeks, including eight week duration in GT1 patients. AbbVie's investigational treatment is a co-formulated combination of 300 mg ABT-493, an NS3/4A protease inhibitor, and 120 mg ABT-530, an NS5A inhibitor.

Protease Inhibitor Collaboration with AbbVie (formerly the research-based pharmaceutical business of Abbott Laboratories)

In December 2006, Enanta and Abbott announced a worldwide agreement to collaborate on the discovery, development and commercialization of HCV NS3 and NS3/4A protease inhibitors and HCV- protease-inhibitor-containing drug combinations. Paritaprevir and ABT-493 are protease inhibitors identified through the collaboration. Under the agreement, AbbVie is responsible for all development and commercialization activities for the collaboration’s lead compound, paritaprevir, as well as ABT-493, the collaboration’s next-generation protease inhibitor. Enanta is eligible to receive annually tiered, double-digit royalties on AbbVie’s worldwide net sales allocable to any of the collaboration’s protease inhibitor products and is eligible to receive up to $80 million in commercial regulatory approval milestones for ABT-493.

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 for viral infections and liver diseases. Enanta has developed novel protease and NS5A inhibitors that are members of the direct-acting-antiviral (DAA) inhibitor classes designed for use against the hepatitis C virus (HCV). Enanta’s protease inhibitors developed through its collaboration with AbbVie include paritaprevir, which is contained in AbbVie’s marketed DAA regimens for HCV, and ABT-493, Enanta’s next-generation protease inhibitor which AbbVie is developing in phase 3 studies in combination with ABT-530, AbbVie’s next-generation NS5A inhibitor. Enanta also has discovered EDP-494, a host-targeted antiviral (HTA) inhibitor for HCV targeted against cyclophilin, which Enanta plans to study in a phase 1 clinical trial beginning in the first quarter of calendar 2016. In addition, Enanta plans to advance into clinical development later in 2016 its program in non-alcoholic steatohepatitis, or NASH, a condition that results in liver inflammation and liver damage caused by a buildup of fat in the liver.

Forward-Looking Statements Disclaimer

This press release contains forward-looking statements, including statements with respect to the prospects for development of AbbVie’s next-generation, pan-genotypic treatment regimen for HCV. Statements that are not historical facts are based on management’s current expectations, estimates, forecasts and projections about Enanta’s business and the industry in which it operates and 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 and risks that may affect actual results include: the efforts of AbbVie (our collaborator on ABT-493) to continue the planned clinical development of next-generation regimens containing ABT-493; regulatory actions affecting any approval of a treatment regimen containing ABT-493 and the impact of competitive products on those regulatory actions; the pricing, market acceptance and reimbursement rates of treatment regimens containing ABT-493 compared to competitive HCV products on the market and product candidates of other companies under development ; and other risk factors described or referred to in “Risk Factors” in Enanta’s most recent Form 10-K for the fiscal year ended September 30, 2015 and any other periodic reports filed more recently with the Securities and Exchange Commission. 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.

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