ENTA Enanta Pharmaceuticals Inc

• Co-Development Option on Next-Generation Protease Inhibitor ABT-493 Not Exercised
• Net Sales Allocations for ABT-450-Containing Regimens Finalized

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 it has decided not to exercise its co-development option for ABT-493, Enanta’s next-generation protease inhibitor for hepatitis C virus (HCV) being developed in Enanta’s collaboration with AbbVie. Per the original collaboration agreement signed in December 2006, Enanta will be eligible for certain regulatory approval milestones as well as royalties on net sales allocable to ABT-493 from worldwide sales of any ABT-493-containing regimens. Enanta also announced that it has reached agreement with AbbVie regarding the net sales allocations for royalty calculations for ABT-450-containing regimens, as well as any regimens containing ABT-493. ABT-450 is the first clinical-stage protease inhibitor candidate developed within the Enanta-AbbVie collaboration, and ABT-493 is the second.

“We believe that the development and commercialization of our HCV protease assets, ABT-450 and ABT-493, are in good hands with the expertise and resources of a global biopharmaceutical company such as AbbVie,” stated Jay R. Luly, Ph.D., President and CEO. “At this time, we have decided it is better to use our financial resources generated by these partnered assets to advance our other internal proprietary candidates for HCV, including our newly reacquired NS5A program, and to pursue the growth of our pipeline beyond HCV with additional candidates in infectious disease and other indications.”

Net Sales Allocations for Protease-Inhibitor-Containing Regimens Used to Calculate Annual RoyaltiesUnder the original agreement with AbbVie, Enanta is entitled to receive payments for regulatory and reimbursement approval milestones, as well as annually tiered royalties per product, ranging from the low double digits up to twenty percent, on AbbVie’s worldwide net sales allocable to the collaboration’s protease inhibitor product. With the amended agreement, the following percentages of worldwide net sales of ABT-450-containing regimens will be the net sales then used to calculate annual royalties payable to Enanta:

       

Protease Inhibitor-ContainingRegimens

   

Percentage of Annual NetSales Used for EnantaRoyalty Calculation

ABT-450-containing 3-DAA regimen(ABT-450/r, ombitasvir and dasabuvir)     30% ABT-450-containing 2-DAA regimen(ABT-450/r, ombitasvir)     45%

For any HCV treatment regimen containing ABT-493, net sales forroyalty purposes will be determined by dividing AbbVie’s worldwidenet sales of the regimen by the number of DAAs in the regimen (e.g.50% of net sales for a 2-DAA regimen and33 1/3% of net sales for a 3-DAA regimen).

 

In addition, although ABT-493 is not currently being developed for sale in combination with any active ingredient other than a DAA, if it were, then there would be a further adjustment to net sales of the regimen for royalty purposes based on the relative value of any non-DAA in the regimen sold by AbbVie.

Protease Inhibitor Collaboration with AbbVieIn 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. ABT-450 and ABT-493 are protease inhibitors identified through the collaboration. Under the agreement, AbbVie is responsible for all development and commercialization activities for ABT-450, the collaboration’s lead compound that has been submitted for approval in the United States and the European Union as part of a multi-drug regimen. Enanta received $57 million in connection with signing the collaboration agreement and $95 million in subsequent clinical and regulatory milestone payments, and is eligible to receive up to an additional $155 million in payments for regulatory and reimbursement approval milestones, as well as annually tiered, double-digit royalties per product on AbbVie’s worldwide net sales allocable to the collaboration’s protease inhibitors.

About EnantaEnanta 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 DisclaimerThis press release contains forward-looking statements, including with respect to the prospects for commercialization of ABT-450-containing regimens, net sales allocations for annual royalty purposes for any future worldwide net sales of ABT-450-containing regimens or ABT-493-containing regimens, and the prospects for the growth of Enanta’s research pipeline in HCV and beyond HCV. 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 the development and commercialization efforts of AbbVie (our collaborator on ABT-450 and ABT-493), regulatory actions affecting approvals of ABT-450-containing regimens and approvals of competitive product candidates in HCV, risks associated with trying to discover new product candidates, and other risk factors described or referred to in “Risk Factors” in Enanta’s most recent Annual Report on Form 10-K for the fiscal year ended September 30, 2013 and in other periodic reports filed 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.

Investor ContactEnanta Pharmaceuticals, Inc.Carol Miceli, 617-607-0710cmiceli@enanta.comorMedia ContactMacDougall Biomedical CommunicationsKari Watson, 781-235-3060kwatson@macbiocom.com