Breakthrough Therapy Designation from the U.S. Food and Drug Administration Granted to Investigational HCV Regimen Containing

  Breakthrough Therapy Designation from the U.S. Food and Drug Administration
  Granted to Investigational HCV Regimen Containing Protease Inhibitor ABT-450

Business Wire

WATERTOWN, Mass. -- May 6, 2013

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’s
investigational direct-acting antiviral (DAA) combination regimen with and
without ribavirin for the treatment of genotype 1 (GT1) hepatitis C virus
(HCV) infection has been designated as a Breakthrough Therapy by the U.S. Food
and Drug Administration (FDA). ABT-450, Enanta’s lead HCV protease inhibitor
identified in its ongoing collaboration with AbbVie, is one of three DAAs in
the regimen.

The all-oral, triple-DAA combination regimen is currently being studied in
Phase 3 clinical trials that are being conducted by AbbVie. The Phase 3
program includes more than 2,000 patients with genotype 1 HCV infection, with
trial sites in 29 countries. The DAAs in the trials include ABT-450/r
(protease inhibitor and ritonavir) combined with two of AbbVie’s proprietary
investigational DAAs, ABT-267 (NS5A inhibitor) and ABT-333 (non-nucleoside
polymerase inhibitor), and are being dosed with and without ribavirin.

According to the FDA, Breakthrough Therapy designation is intended to expedite
the development and review of drugs for serious or life-threatening
conditions. The criteria for Breakthrough Therapy designation include
preliminary clinical evidence demonstrating a drug may have substantial
improvement on at least one clinically significant endpoint compared to
available therapy. A Breakthrough Therapy designation conveys all of the fast
track program features, as well as more intensive FDA guidance on an efficient
drug development program.^1

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

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. Under the agreement, AbbVie (as the successor to Abbott) is
responsible for all development and commercialization activities for ABT-450.
Enanta received a $57 million upfront payment upon signing the collaboration
agreement, has received all 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. developmentcosts and U.S. commercialization efforts(sales and
promotion costs) inexchange for 40 percent of any U.S. profits ultimately
achieved afterregulatory approval instead ofreceiving payments for U.S.
commercialregulatory approval milestones and royalties on U.S. sales.

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 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 class
of host-targeted antiviral (HTA) inhibitors targeted against cyclophilin.
Additionally, Enanta has created a new class of antibiotics, called
Bicyclolides, for the treatment of multi-drug resistant bacteria, with a
current focus on developing an intravenous and oral treatment for hospital and
community MRSA (methicillin-resistant Staphylococcus aureus) infections.

Forward-Looking Statement Disclaimer

This press release contains forward-looking statements, including statements
with respect to the Breakthrough Therapy designation that the FDA has given to
AbbVie’s regimen containing ABT-450 for treatment of genotype 1 HCV infection
and milestones and royalties that Enanta is eligible to receive on ABT-450 and
any additional collaboration protease inhibitor products. 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 development and commercialization efforts of
AbbVie for HCV treatment regimens containing ABT-450 or any additional
collaboration protease inhibitor product, regulatory actions affecting
clinical development or treatment regimens containing ABT-450 or any
additional collaboration protease inhibitor product, 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.

^1U.S. Food and Drug Administration. Frequently Asked Questions: Breakthrough
Therapies. 2013.


Carol Miceli, 617-607-0710
Enanta Pharmaceuticals, Inc.
Kari Watson, 781-235-3060
MacDougall Biomedical Communications
Press spacebar to pause and continue. Press esc to stop.