First of Six All-Oral, Interferon-Free Phase 3 Hepatitis C
Studies Using Regimen Containing ABT-450
Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA) today announced
results from the SAPPHIRE-I study, one of six phase 3
registrational studies being conducted by AbbVie for the treatment
of hepatitis C virus (HCV) genotype 1 (GT1) infection, using a
regimen containing Enanta’s lead protease inhibitor ABT-450.
ABT-450 is part AbbVie’s investigational three direct-acting
antiviral (3D) regimen, consisting of boosted protease inhibitor
ABT-450/ritonavir, NS5A inhibitor ABT-267, and non-nucleoside
polymerase inhibitor ABT-333. The SAPPHIRE-I study used this 3D
regimen plus ribavirin.
Results from the 631 patient SAPPHIRE-I trial demonstrated a
sustained virologic response at 12 weeks post-treatment (SVR12) of
96 percent in treatment-naïve adult patients chronically infected
with GT1 HCV. The majority of patients were GT1a, considered the
more difficult-to-treat subtype, and the SVR12 rates of GT1a and
GT1b were 95 percent and 98 percent, respectively. These results
were based on an intent-to-treat analysis and were achieved after
12 weeks of treatment. The rate of virologic relapse or
breakthrough was low, occurring in 1.7 percent of patients
receiving the 3D regimen. The treatment regimen was well tolerated,
with an equal percentage of patients in the active and placebo arms
(0.6 percent) discontinuing treatment due to adverse events.
“Achieving high SVR rates in this trial is an important step
toward our goal of providing a well-tolerated and highly effective
all-oral treatment option that doesn’t currently exist for this
important patient population,” stated Jay R. Luly, Ph.D., President
and Chief Executive Officer.
About Study M11-646 (SAPPHIRE-I)
SAPPHIRE-I is a global, multi-center, randomized, double-blind,
placebo-controlled study to evaluate the efficacy and safety of 12
weeks of treatment with ABT-333 (250mg), ribavirin (weight-based),
both dosed twice daily, and the fixed-dose combination of
ABT-450/ritonavir (150/100mg) co-formulated with ABT-267 (25mg) and
dosed once daily in non-cirrhotic, GT1a and GT1b HCV-infected,
treatment-naïve adult patients.
The study population consisted of 631 GT1 treatment-naïve
patients with no evidence of liver cirrhosis. 473 patients were
randomized to the 3D regimen plus ribavirin for 12 weeks, and 158
patients were randomized to placebo for the initial 12 weeks.
Patients initially randomized to placebo for the first 12 weeks
then received open-label treatment with the 3D regimen plus
ribavirin for 12 weeks.
Following 12 weeks of treatment with AbbVie’s 3D regimen plus
ribavirin, 96 percent (n=455/473) of patients achieved SVR12 based
on intent-to-treat analysis where patients with missing values for
any reason were considered treatment failures. In the active
treatment arm, patients with GT1b infection achieved 98 percent
SVR12 (148/151), while patients with GT1a achieved 95 percent SVR12
(307/322).
The most commonly reported adverse events in the 3D and placebo
arms, respectively, were fatigue, headache and nausea.
Discontinuations due to adverse events were reported in 0.6 percent
of patients receiving the 3D regimen and 0.6 percent of patients
receiving placebo. The rate of virologic relapse or breakthrough
was low, occurring in 1.7 percent of patients receiving the 3D
regimen.
AbbVie has announced that results from the remaining five
ABT-450 containing studies in AbbVie’s phase 3 program will be
available in the coming months, supporting regulatory submissions
starting in the second quarter of 2014. AbbVie will disclose
detailed SAPPHIRE-I results at future scientific congresses and in
publications.
Overview of AbbVie’s phase 3 clinical programs:
Study Patients (N)
Treatment Regimen Treatment Duration
SAPPHIRE-I GT1, treatment-naïve(631)
- ABT-450/rb +ABT-267c
- ABT-333
- Ribavirin
12 weeks
12 weeks, then active treatment for 12 weeks
SAPPHIRE-II GT1, treatment-experienced(400a)
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
12 weeks
12 weeks, then active treatment for 12 weeks PEARL-II
GT1b, treatment-experienced(210 a)
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
12 weeks
- ABT-450/r +ABT-267
- ABT-333
12 weeks PEARL-III GT1b, treatment-naïve(400 a)
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
12 weeks
- ABT-450/r +ABT-267
- ABT-333
- Placebo
12 weeks PEARL-IV GT1a, treatment-naïve(300 a)
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
12 weeks
- ABT-450/r +ABT-267
- ABT-333
- Placebo
12 weeks TURQUOISE-II GT1, treatment-naïve and
treatment-experienced (with compensated cirrhosis)(380 a)
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
12 weeks
- ABT-450/r +ABT-267
- ABT-333
- Ribavirin
24 weeks
a projected study populationb ABT-450/ritonavirc ABT-267 is
co-formulated with ABT-450/r, administered as two pills once
daily
ABT-450 is currently being studied in combination with other
AbbVie compounds in multiple phase 3 all-oral, interferon-free
clinical studies for HCV. Additional information about AbbVie’s
phase 3 studies can be found on www.clinicaltrials.gov.
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. ABT-450 is a
protease inhibitor identified as a lead compound through the
collaboration. Under the agreement, AbbVie is responsible for all
development and commercialization activities for ABT-450. Enanta
received $57 million in connection with signing the collaboration
agreement, has received $55 million in subsequent clinical
milestone payments, and is eligible to receive an additional $195
million in payments for regulatory milestones, as well as
double-digit royalties worldwide on any revenue allocable to the
collaboration’s protease inhibitors. Also, for any additional
collaborative HCV protease inhibitor product candidate developed
under the agreement, Enanta holds an option to modify the U.S.
portion of it rights to receive milestone payments and worldwide
royalties. With this option, Enanta can fund 40 percent of
U.S. development costs and U.S. commercialization
efforts (sales and promotion costs) for the additional
protease inhibitor in exchange for 40 percent of any U.S.
profits ultimately achieved after regulatory approval, instead
of receiving payments for U.S. commercial regulatory
approval milestones and royalties on U.S. sales of that protease
inhibitor.
About Hepatitis C Virus (HCV)
Hepatitis C is a liver disease affecting over 170 million people
worldwide. The virus is typically spread through direct contact
with the blood of an infected person. Hepatitis C increases a
person’s risk of developing chronic liver disease, cirrhosis, liver
cancer and death. There is an acute need for new HCV therapies that
are safer and more effective for many variants of the virus.
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 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 (partnered with Novartis) 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 Disclaimer
This press release contains forward-looking statements,
including with respect to clinical data, plans for announcing
additional data, and the planned clinical development and
regulatory submissions for ABT-450. 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 final results of
ongoing clinical trials, the development and marketing efforts of
AbbVie (our collaborator on ABT-450), regulatory actions affecting
clinical development of ABT-450 and clinical development of
competitive product candidates. 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:Carol Miceli,
617-607-0710cmiceli@enanta.comorMedia:MacDougall Biomedical
CommunicationsKari Watson, 781-235-3060kwatson@macbiocom.com
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