WATERTOWN, Mass.--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a research and development-focused biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, announced today that new data from AbbVie’s phase 3 GIFT-I study, its investigational, all-oral, interferon (IFN)- and ribavirin (RBV)-free, two direct-acting antiviral treatment with ombitasvir/paritaprevir/ritonavir, was presented at the Annual Meeting of the Japan Society of Hepatology in Kumamoto, Japan.1
GIFT-I evaluated genotype 1b (GT1b) chronic hepatitis C virus (HCV) infected Japanese patients, with and without cirrhosis, who were either treatment-naïve or Interferon (with or without RBV) treatment-experienced.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 IFN and had a high viral load.1 In study results related to the secondary endpoint, GT1b HCV patients with compensated cirrhosis achieved 91 percent (n=38/42) SVR12.
In an additional intent-to-treat (ITT) analysis, SVR12 was achieved in 98 percent (n=104/106) of the GT1b HCV infected patients without cirrhosis (Arm B) who were randomized to initially receive double-blind placebo for 12 weeks, followed by open-label treatment with ombitasvir/paritaprevir/ritonavir.1 The ITT population included every patient that was randomized to placebo and received at least one dose of active, open-label study drug.
Across all study arms, three patients (n=3/363) discontinued treatment due to adverse events.1 The most commonly reported adverse events (>5 percent in any arm) were nasopharyngitis, headache, peripheral edema, nausea, pyrexia and decreased platelet count.1
In Japan, approximately 1.5 to 2 million people are living with HCV.2 60 to 70 percent of Japanese HCV patients are infected with Genotype 1, and of those, about 95 percent are infected with the GT1b sub-type.3 AbbVie studied its two direct-acting antiviral treatment regimen without RBV in Japan due to patient and viral characteristics specific to the Japanese population, including high prevalence of GT1b.
Paritaprevir is Enanta’s lead protease inhibitor identified within the ongoing Enanta-AbbVie collaboration and is one of the two direct-acting antivirals (2-DAA) in AbbVie’s treatment regimen currently under priority review by the Japanese Ministry of Health, Labour and Welfare. AbbVie has previously announced that it expects regulatory approval of the 2-DAA treatment regimen in Japan in the second half of 2015. Upon commercialization regulatory approval in Japan, Enanta will be entitled to a $30 million milestone payment from AbbVie. In addition, Enanta will be eligible to receive annually tiered royalties, ranging from the low double digits up to twenty percent, on AbbVie’s aggregate net sales of all paritaprevir-containing regimens, including 45% of AbbVie’s worldwide net sales of any 2-DAA regimen.
Paritaprevir is included in AbbVie’s HCV treatment regimens approved in the U.S. in late 2014 and in the E.U. in early 2015.
About GIFT-I Study
GIFT-I comprises 363 patients in two
sub-studies. In sub-study 1, 321 genotype 1b (GT1b) patients without
cirrhosis, both treatment-naïve and interferon (IFN) [with or without
ribavirin (RBV)] treatment-experienced, were randomized to receive
either ombitasvir/paritaprevir/ritonavir (Arm A) [OBV/PTV/r] or placebo
(Arm B) [2:1 randomization ratio, stratified by treatment history, past
response, viral load and IFN eligibility]. Patients initially randomized
to placebo (Arm B) then received OBV/PTV/r for an additional 12 weeks of
open-label treatment. Sustained virologic response was assessed 12 weeks
post-treatment (SVR12) as a primary efficacy endpoint in a sub-group of
previously untreated, non-cirrhotic GT1b patients who were eligible for
therapy with IFN and had a high viral load, defined as an HCV RNA level
≥ 100,000 IU/mL and received at least one dose of the double-blind,
active study drug.1
In sub-study 2, 42 GT1b treatment-naïve and IFN (with our without RBV) treatment-experienced patients with compensated cirrhosis received open-label treatment for 12 weeks (Arm C) with SVR12 and assessed as a secondary efficacy endpoint.1
One patient from each arm (n=3/363) experienced on-treatment virologic failure [Arm A, 0.5% (n=1/215); Arm B, 0.9% (n=1/106); Arm C, 2.4% (n=1/42)].1 Across all arms, eight patients (n=8/354) experienced post-treatment relapse [Arm A, 2.4% (n=5/209); Arm B, 1.0% (n=1/105); Arm C, 5.0% (n=2/40)].1
Protease Inhibitor Collaboration with AbbVie
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. AbbVie is Abbott’s successor under
the agreement and is responsible for all development and
commercialization activities for paritaprevir, as well as ABT-493, the
collaboration’s next-generation protease inhibitor.
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 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. In addition, Enanta has a preclinical program in
non-alcoholic steatohepatitis, or NASH, which is a condition that
results in liver inflammation and damage caused by a buildup of fat in
the liver.
Forward Looking Statements Disclaimer
This press release
contains forward-looking statements, including with respect to the
prospects for AbbVie’s paritaprevir-containing, 2-DAA regimen under
development for HCV in Japan. . 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 efforts of AbbVie
(our collaborator on paritaprevir) regarding regulatory approval and
commercialization in Japan for AbbVie’s treatment regimens containing
paritaprevir and for competitive treatment regimens; the level of market
acceptance and the pricing and rate of reimbursement for the AbbVie’s
regimen in Japan; the impact of competitive products on the use and
sales of the AbbVie regimen in Japan; 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, 2014 and 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.
1 Chayama K, et al. Ombitasvir/paritaprevir/ritonavir for Treatment of HCV Genotype 1b in Japanese Patients With or Without Cirrhosis: Results from GIFT-I. Presented at the Annual Meeting of the Japan Society of Hepatology. May 21-23; Kumamoto, Japan
2 Kohnodai Hospital. National Center for Global Health and Medicine [cited 20 February 2013]. Available from: http://www.ncgm.go.jp/center/forpatient_hcv.html
3 Hajarizadeh B et al. Nat Rev Gastroenterol Hepatol 2013; 10: 553-562. http://www.nature.com/nrgastro/journal/v10/n9/fig_tab/nrgastro.2013.107_F1.html