Enanta Pharma Reports Update on Collaboration Deal with AbbVie: Will Not Exercise Option for Co-Development, Co. Received $57M Related to Signing, $95M in Milestones

Enanta Pharmaceuticals, Inc.,

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 Royalties Under 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-Containing Percentage of Annual Net Regimens     Sales Used for Enanta Royalty Calculation ABT-450-containing 3-DAA regimen     30% (ABT-450/r, ombitasvir and dasabuvir) ABT-450-containing 2-DAA regimen     45% (ABT-450/r, ombitasvir) For any HCV treatment regimen containing ABT-493, net sales for royalty purposes will be determined by dividing AbbVie's worldwide net sales of the regimen by the number of DAAs in the regimen (e.g. 50% of net sales for a 2-DAA regimen and 33 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.