Enanta Pharmaceuticals Reports Financial Results for its Fiscal First Quarter Ended

Enanta Pharmaceuticals Reports Financial Results for its

Fiscal First Quarter Ended December 31, 2014

February 5, 2015 Enanta Pharmaceuticals, Inc., (NASDAQ: ENTA), a research and development-focused biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, today reported financial results

for its fiscal first quarter ended December 31, 2014.

Fiscal First Quarter Ended December 31, 2014 Financial Results

Revenue for the three months ended December 31, 2014 was $77.5 million, compared to $0.9 million for the three months ended December 31, 2013. The

increase in revenue for the most recent quarter was primarily due to the achievement of a $75 million milestone payable from AbbVie for the U.S. regulatory approval of VIEKIRA PAK , as well

as $1.4 million in royalty revenue, which was earned from a portion of AbbVie s net sales of VIEKIRA PAK in the U.S. from the December 19, 2014 approval date through December 31, 2014. VIEKIRA PAK contains paritaprevir, Enanta s

lead hepatitis C virus (HCV) protease inhibitor identified within the ongoing AbbVie-Enanta collaboration, and is one of the direct-acting antivirals in the regimen. Milestone payments, royalties and other payments from collaborations have varied

significantly from period to period, and are expected to continue to do so.

Research and development expenses totaled $4.5 million for the three months

ended December 31, 2014, compared to $4.3 million for the three months ended December 31, 2013. The increase in the three month period is primarily due to increased spending on Enanta s proprietary research programs.

General and administrative expenses totaled $2.8 million for the three months ended December 31, 2014, compared to $2.1 million for the three months

ended December 31, 2013. The increase in the three month period primarily reflects increases in stock-based compensation expense, due principally to increases in Enanta s stock price, as well as additional expenses incurred as Enanta

expands its operations.

Net income for the three months ended December 31, 2014 was $42.0 million, or $2.18 per diluted common share, compared to a

net loss of $5.4 million, or $(0.30) per diluted common share, for the corresponding period in 2013. The increase in net income during the three-month period ended December 31, 2014 was primarily due to the milestone amount of $75 million

payable from AbbVie.

Cash, cash equivalents and short-term and long-term marketable securities totaled $127.6 million at

December 31, 2014, excluding the $75 million milestone earned but not received during the quarter. This compares to a total of $131.8 million in such accounts at September 30, 2014. Enanta expects that its current cash, cash equivalents

and marketable securities will be sufficient to meet its anticipated cash requirements for at least the next 24 months.

Our first wave of HCV

market opportunity has begun with our HCV partner AbbVie s recent U.S. and European marketing approvals for VIEKIRA PAK and VIEKIRAX , respectively, commented Jay R. Luly,

Ph.D., President and Chief Executive Officer. With a third potential HCV regimen approval anticipated in Japan later this year, and our next generation protease inhibitor candidate expected to advance into phase 3 studies this year as well,

Enanta expects to have a portfolio of revenue-producing assets to support our research and development in new therapeutic areas of growth, beginning with our new NASH program targeting candidate selection for later this year.

Program and Business Review of the Quarter

Recent Developments since January 1, 2015

Upcoming Events and Presentations

Enanta management will participate in the following upcoming investor conferences and events:

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 liver damage caused by a buildup of fat in the liver.

Forward Looking Statements Disclaimer

contains forward-looking statements, including statements with respect to the prospects for regulatory filing and approval in Japan for AbbVie s HCV treatment regimen containing paritaprevir, the prospects for AbbVie s development of a

regimen containing ABT-493, the prospects for completion of a proof-of-concept study of EDP-239, the prospects for selection of a NASH development candidate, the prospects for future revenues generated from products sales and development and the

projected sufficiency of Enanta s cash-equivalent resources and marketable securities. Statements that are not historical facts are based on management s current expectations, estimates, forecasts and projections about Enanta s

business and the industry in which it operates and 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 and risks that may affect actual results include: Enanta s reliance on AbbVie s

planned regulatory approval and commercialization efforts for its treatment regimens containing paritaprevir; Enanta s reliance on AbbVie s planned clinical development of ABT-493; regulatory actions affecting further approvals of

treatment regimens containing paritaprevir or any approval of a treatment regimen containing ABT-493; the pricing, market acceptance and reimbursement rates of such treatment regimens compared to competitive HCV product candidates of other

companies; the risk of early stage discovery efforts in new disease areas; Enanta s lack of clinical development experience; Enanta s need to attract and retain senior management and key scientific personnel; Enanta s need to obtain

and maintain patent protection for its product candidates and avoid

potential infringement of the intellectual property rights of others; 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.

ENANTA PHARMACEUTICALS, INC.

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share amounts)

ENANTA PHARMACEUTICALS, INC.

CONDENSED CONSOLIDATED BALANCE SHEETS

Enanta Pharmaceuticals, Inc.

MacDougall Biomedical Communications