- Second 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-II study, the second 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 of 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-II study used this 3D
regimen plus ribavirin.
Results from the 394-patient SAPPHIRE-II trial demonstrated a
sustained virologic response at 12 weeks post-treatment (SVR12) of
96 percent in chronically infected GT1 HCV treatment experienced
adult patients who had previously failed pegylated interferon and
ribavirin treatment. Approximately 49 percent of these patients
were prior null responders, namely patients defined as not
achieving a significant reduction in the HCV virus during their
prior treatment. The majority of patients were GT1a, considered the
more difficult-to-treat subtype, and the SVR12 rates of GT1a and
GT1b were 96 percent and 97 percent, respectively. These results
were based on an intent-to-treat analysis and were achieved after
12 weeks of treatment. Virologic relapse or breakthrough was noted
in 2 percent of patients receiving the 3D regimen plus ribavirin.
The treatment regimen was well tolerated, with 1 percent of
patients discontinuing treatment due to adverse events.
“The high SVR rates in this SAPPHIRE-II trial and the previously
reported SAPPHIRE-I trial further validate this 3D regimen plus
ribavirin for both treatment-naive and treatment-experienced
patients,” stated Jay R. Luly, Ph.D., President and Chief Executive
Officer. “We look forward to the remaining phase 3 studies reading
out using the same 3D regimen with and without ribavirin, as well
as in the treatment of HCV patients with cirrhosis.”
About Study M13-098 (SAPPHIRE-II)
Following SAPPHIRE-I, SAPPHIRE-II is the second
placebo-controlled trial and the second of six phase 3 trials
supporting AbbVie’s investigational 3D regimen for the treatment of
GT1 hepatitis C patients. AbbVie will disclose detailed SAPPHIRE-II
results at future scientific congresses and in publications.
SAPPHIRE-II 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, co-formulated
combination of ABT-450/ritonavir (150/100mg) and ABT-267 (25mg)
dosed once daily in non-cirrhotic, GT1a and GT1b HCV-infected,
treatment-experienced adult patients who previously failed
treatment with pegylated interferon and ribavirin.
The study population consisted of 394 GT1 treatment-experienced
patients with no evidence of liver cirrhosis. 297 patients were
randomized to the 3D regimen plus ribavirin for 12 weeks, and 97
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. In the study, 49 percent of patients were
prior null responders to pegylated interferon and ribavirin,
generally considered among the most difficult to treat
successfully.
Following 12 weeks of treatment with AbbVie’s 3D regimen plus
ribavirin, 96 percent (n=286/297) of patients achieved SVR12 based
on an intent-to-treat analysis, where patients with missing values
for any reason were considered treatment failures. The SVR12 rates
in GT1a and GT1b patients were 96 percent (166/173) and 97 percent
(119/123), respectively. One subject had HCV genotype 1 and
achieved SVR12, but was unable to be sub-genotyped.
The most commonly reported adverse events in both the 3D and
placebo arms were headache, fatigue and nausea. Discontinuations
due to adverse events were reported in three (1 percent) patients
receiving the 3D regimen and no patients receiving placebo.
Virologic relapse or breakthrough was noted in 2 percent of
patients receiving the 3D regimen plus ribavirin.
AbbVie has announced that results from the remaining four
ABT-450 containing studies in AbbVie’s phase 3 program will be
available in the coming months.
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(394)
- 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/ritonavircABT-267 is
co-formulated with ABT-450/r, administered as two pills once
daily
Additional information about AbbVie’s phase 3 studies can be
found at 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 ContactCarol Miceli,
617-607-0710cmiceli@enanta.comorMedia ContactMacDougall
Biomedical CommunicationsKari Watson,
781-235-3060kwatson@macbiocom.com
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