Enanta Pharmaceuticals Announces New Drug Application Submission to the U.S. FDA for All-Oral, Interferon-Free Hepatitis C

  Enanta Pharmaceuticals Announces New Drug Application Submission to the U.S.
  FDA for All-Oral, Interferon-Free Hepatitis C Regimen

                 Filing Triggers Milestone Payment to Enanta

  *AbbVie’s submission to FDA triggers $20 million milestone payment to
  *Regimen includes Enanta’s and AbbVie’s protease inhibitor ABT-450

Business Wire

WATERTOWN, Mass. -- April 22, 2014

Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a research and development-focused
biotechnology company dedicated to creating small molecule drugs in the
infectious disease field, today announced that AbbVie, Enanta’s collaboration
partner for ABT-450, has submitted a New Drug Application (NDA) to the U.S.
Food and Drug Administration (FDA) seeking approval for an investigational,
all-oral, interferon-free regimen for the treatment of adult patients with
chronic genotype 1 (GT1) hepatitis C virus (HCV) infection.

The three direct-acting antiviral regimen consists of boosted protease
inhibitor ABT-450/ritonavir, NS5A inhibitor ABT-267, and non-nucleoside
polymerase inhibitor ABT-333. ABT-450 is the lead protease inhibitor developed
through Enanta’s collaboration with AbbVie.

The U.S. NDA filing triggers a $20 million milestone payment to Enanta from
AbbVie. AbbVie also plans to submit applications for regulatory approval of
its regimen in the European Union in early May. Enanta is entitled to receive
an additional $20 million upon the first regulatory filing in the European
Union for a regimen containing a collaboration compound.

The NDA is supported by AbbVie’s data from the largest all-oral,
interferon-free clinical program in GT1 patients conducted to date,^1 with six
phase 3 studies that included more than 2,300 patients in over 25 countries.

“This submission marks a very significant step toward Enanta being part of the
first wave of all-oral therapies that may be approved to treat patients with
genotype 1 hepatitis C virus,” stated Jay R. Luly, Ph.D., Enanta’s President
and Chief Executive Officer. “No all-oral therapy has yet been approved to
treat GT1 HCV infection, which is estimated to affect approximately 70% of the
3.2 million people of the U.S. population infected with HCV.”^2

In May of 2013, AbbVie's investigational direct-acting antiviral (DAA) regimen
with and without ribavirin for HCV genotype 1 was designated as a Breakthrough
Therapy by the U.S. FDA. This designation is intended to help expedite the
development of drugs for serious or life-threatening conditions and is based
in part on preliminary clinical evidence demonstrating a drug or regimen may
have substantial improvement on at least one clinically significant endpoint
compared to available therapy.

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. 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, is entitled to receive
$20 million in connection with the NDA filing in the U.S. described above, and
is eligible to receive up to an additional $175 million in payments for
regulatory and commercialization 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 ABT-450

ABT-450 is an NS3 protease inhibitor discovered through Enanta’s ongoing
collaboration with AbbVie. AbbVie and Enanta have an agreement to collaborate
on the discovery, development and commercialization of HCV NS3 and NS3/4A
protease inhibitors. Protease inhibitors play an essential role in the viral
life cycle of the hepatitis C virus (HCV). Inhibition of the protease prevents
non-structural (NS) proteins from forming and thereby prevents replication and
survival of the HCV virus. ABT-450 is part of AbbVie’s investigational regimen
for HCV that consists of boosted protease inhibitor ABT-450/ritonavir
(referred to as ABT-450/r), NS5A inhibitor ABT-267 and non-nucleoside
polymerase inhibitor ABT-333.

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 statements
with respect to the prospects for regulatory filings for AbbVie’s HCV
treatment regimen containing ABT-450 and the prospects for milestone payments
to Enanta resulting from such filings and any subsequent regulatory approvals.
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
ABT-450) to obtain regulatory approvals and commercialize treatment regimens
containing ABT-450, the development, regulatory and marketing efforts of
others with respect to competitive treatment regimens, regulatory actions
affecting any ABT-450-containing regimen, any competitive regimen, or both,
and the level of market acceptance and the rate of reimbursement for any
ABT-450-containing regimen. 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

^1 Comparison based on review of data from www.clinicaltrials.gov for phase 3a
programs of Gilead, BMS and BI as of November 15, 2013.

^2 http://www.cdc.gov/hepatitis/HCV/PDFs/HepCGeneralFactSheet.pdf;


Investor Contact
Enanta Pharmaceuticals, Inc.
Carol Miceli, 617-607-0710
Media Contact
MacDougall Biomedical Communications
Kari Watson, 781-235-3060
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