UPDATE: Enanta Announces Approval of Viekirax For Hepatitis C in Japan

Enanta Pharmaceuticals, Inc., ENTA a research and development-focused biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, today announced that the Japanese Ministry of Health, Labour and Welfare (MHLW) approved AbbVie's VIEKIRAX® (ombitasvir/paritaprevir/ritonavir), as a new interferon-free and ribavirin-free treatment option for adult patients in Japan with chronic genotype 1 (GT1) hepatitis C virus (HCV) infection, including those with compensated liver cirrhosis.1 VIEKIRAX consists of two-direct-acting antiviral (2-DAA), fixed-dose tablets containing paritaprevir/ritonavir with ombitasvir. VIEKIRAX is approved in Japan using once daily dosing for 12 weeks for GT1 HCV patients. Paritaprevir is Enanta's lead protease inhibitor identified within the ongoing Enanta-AbbVie collaboration and is one of the two DAAs in AbbVie's VIEKIRAX. Japan has one of the highest rates of hepatitis C infection in the industrialized world, with approximately 1.5 to 2 million people living with HCV.2, 3 Genotype 1 is the most common HCV genotype in Japan with 60 to 70 percent of patients infected and, of those, about 95 percent are infected with the genotype 1b (GT1b) sub-type.4 Enanta expects to earn and receive a $30 million milestone payment in the quarter ending December 31, 2015 upon price reimbursement approval of VIEKIRAX in Japan. In addition, forty five percent of AbbVie's net sales of the 2-DAA regimen in Japan will be included in the worldwide paritaprevir net sales on which Enanta is eligible to receive annually tiered royalties, ranging from the low double digits up to twenty percent. AbbVie is responsible for all worldwide development and commercialization of VIEKIRAX and other HCV treatment regimens containing paritaprevir. Paritaprevir/ritonavir and ombitasvir, AbbVie's NS5A inhibitor, are also included in AbbVie's 3-DAA VIEKIRA PAK™ regimen, which was approved in the U.S. in late 2014 for patients with GT1 HCV infection. VIEKIRAX was first approved under that name in Europe in January 2015. "The approval of VIEKIRAX in Japan marks another major territory in which a regimen containing paritaprevir is approved," stated Jay R. Luly, Ph.D., President and CEO. "VIEKIRAX offers HCV patients in Japan an all-oral, once daily treatment option that has demonstrated high cure rates. We are proud that paritaprevir is part of this regimen." The approval was supported by the phase 3 GIFT-I study.1 An overall 95 percent (n=140/148) of treatment-naïve and 94 percent (n=102/109) of treatment-experienced GT1b HCV infected patients achieved SVR12 with VIEKIRAX.1 The primary endpoint was achieved, demonstrating 95 percent (n=106/112) SVR12 in a sub-group of treatment-naïve, non-cirrhotic, adult, GT1b HCV infected Japanese patients who were eligible for therapy with interferon (IFN) and had a high viral load. A secondary endpoint in GT1b HCV patients with compensated cirrhosis achieved 91 percent (n=38/42) SVR12.5 Across all treatment arms, three patients (n=3/363) experienced on-treatment virologic failure, eight patients (n=8/354) experienced post-treatment relapse and three patients discontinued treatment due to adverse events. The most commonly reported adverse events (>5 percent in any arm) were nasopharyngitis, headache, peripheral edema, nausea, pyrexia and decreased platelet count.5 In April 2015, the Japanese MHLW granted AbbVie priority review for VIEKIRAX on the basis of clinical usefulness of the treatment and recognizing the severity and unmet need of HCV in Japan.