Enanta Pharmaceuticals to Provide Updates on its Research and Development Programs and Outlook for 2021 at the 39th Annual J.P. Morgan Healthcare Conference

• Announces New Oral HBV RNA Destabilizer, EDP-721, as an Additional Component Toward Functional HBV Cure; Expects to Initiate Phase 1 Study Mid-2021
• Expands RSV Program with Introduction of Discovery Initiative for RSV L-Inhibitors
• Initiated RSVTx, a Phase 2b Study of EDP-938 in Adult Hematopoietic Cell Transplant Recipients with Acute RSV Infection
• Strong Cash Balance of $419 Million at September 30, 2020 Supports Expanding Research and Development Programs

WATERTOWN, Mass.--(BUSINESS WIRE)--Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a clinical-stage biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, today announced that Jay R. Luly, Ph.D., Enanta’s President and Chief Executive Officer, will provide an update across its pipeline programs in virology and non-alcoholic steatohepatitis (NASH), including its newest candidate, EDP-721, a novel oral hepatitis B virus (HBV) RNA destabilizer and the expansion of its respiratory syncytial virus (RSV) platform with a new RSV-L inhibitor program, as well as provide an update on its plans for 2021 during Enanta’s presentation at the 39^th Annual J.P. Morgan Healthcare Conference on January 12, 2021 at 8:20 a.m. ET.

“Throughout 2020, Enanta made meaningful progress with the initiation of five clinical trials across our pipeline. We look forward to building on this momentum in 2021, starting with the introduction today of our newest HBV clinical candidate, EDP-721, a novel RNA destabilizer with the potential to reduce the production of multiple HBV proteins, which we believe could be a key component in achieving a functional cure in this indication,” stated Jay R. Luly, President and Chief Executive Officer of Enanta Pharmaceuticals. “Robust pre-clinical data has demonstrated that EDP-721 has the potential to reduce HBsAg production with HBV pan-genomic activity and exhibits additive to synergistic activity with approved nucleoside therapies and with Enanta’s HBV core inhibitor, EDP-514. These data give us the confidence to progress EDP-721 into a Phase 1 clinical study by mid-2021, bringing us one step closer to developing an all-oral, triple regimen that could be a functional cure for patients living with chronic HBV.”

“We are also excited about the expansion of our RSV program, highlighted by our new discovery of potent RSV L-inhibitors. We look forward to continuing our progress throughout 2021 with multiple milestones expected across our pipeline, including the initiation of our Phase 2 study of EDP-938 in pediatric patients with RSV this quarter, preliminary data from two Phase 1b studies of EDP-514 in HBV in the second quarter, and results from our Phase 1 study of EDP-297 in development for the treatment of NASH, also in the second quarter. Furthermore, we expect to have preliminary information from an initial interim analysis of our Phase 2b NASH study of EDP-305 around mid-year, which we will use to help with further internal assessment of our NASH program,” continued Dr. Luly. “Overall, 2021 is shaping up to be an exciting, catalyst-heavy year for Enanta, and we believe we are well-positioned to extend our track record of success heading into the new year.”

During the presentation, Dr. Luly will discuss Enanta’s pipeline program updates and expectations for 2021.

Pipeline Programs Update and Review

Virology

Hepatitis B Virus

• EDP-721, Enanta’s newest clinical candidate, is a potent and selective HBV RNA destabilizer, which has demonstrated a robust reduction of viral transcripts in preclinical models, leading to reduced production of multiple HBV proteins, including HBV surface antigen (HBsAg) and e-antigen (HBeAg). By targeting HBV RNA, EDP-721 is expected to reduce HBsAg derived from both integrated and covalently-closed circular DNA (cccDNA). Since high levels of HBsAg are known to suppress innate and adaptive immune responses, which are believed to occur through multiple mechanisms, a sustained reduction of HBsAg is regarded as a key component of a functional cure for HBV. Enanta plans to develop EDP-721 for use alone or in combination with other mechanisms, such as EDP-514, with the ultimate goal of achieving a functional cure. Enanta expects to initiate a Phase 1 clinical study of EDP-721 in mid-2021.
• EDP-514, Enanta’s core inhibitor with Fast Track Designation from the FDA, is being developed in two Phase 1b studies for the treatment of HBV across different patient populations: subjects on treatment with a nucleos(t)ide reverse transcriptase inhibitor (NUC-suppressed patients), and chronic HBV subjects with high viral loads who are not currently on therapy (viremic patients). Preliminary data is expected for both trials in the second quarter of 2021.

Respiratory Syncytial Virus

• EDP-938, Enanta’s N-protein inhibitor with Fast Track Designation from the FDA, is being evaluated in a broad clinical development program, consisting of three trials.
  • In December, Enanta initiated RSVTx, a Phase 2b, randomized, double-blind, placebo-controlled, multicenter study evaluating the efficacy and safety of EDP-938 in adult hematopoietic cell transplant recipients with acute RSV infection and symptoms of upper respiratory tract infection. The company plans to enroll, within 72 hours of symptom onset, approximately 200 adult subjects 18 to 75 years of age, who will receive EDP-938 or placebo for 21 days. The primary endpoint is the incidence of lower respiratory tract complications within 28 days of enrollment, while secondary endpoints include change from baseline in RSV RNA viral load, safety and pharmacokinetics.
  • RSVP, a Phase 2b randomized, double-blind, placebo-controlled study in 70 adult outpatients with community-acquired RSV infection, is ongoing, but to date the 2021 RSV season in the Northern Hemisphere has not yet begun due to COVID-19 mitigation measures. Enanta has made extensive efforts to expand its clinical sites beyond North America, including sites across the EU and Asia-Pacific, to be ready when RSV infection arrives. The company will provide further guidance on trial completion once RSV becomes prevalent again.
  • RSVPEDs, a Phase 2 randomized, double-blind, placebo-controlled study in hospitalized and non-hospitalized pediatric RSV patients age 28 days to 24 months, is expected to initiate in early 2021.

Virology Discovery Programs – In 2021, Enanta anticipates identifying development candidates for two of its three virology discovery programs listed below:

Respiratory Syncytial Virus

• The RSV L-protein is a viral RNA-dependent RNA polymerase that contains multiple enzyme activities required for RSV replication. Today, Enanta announced the expansion of its RSV program with the introduction of an RSV L-inhibitor discovery initiative that includes potent nanomolar leads active against both RSV-A and RSV-B. An RSV-L-inhibitor is not expected to have cross-resistance to other classes of inhibitors, and therefore can potentially be used alone or in combination with agents targeting other RSV mechanisms, such as EDP-938.

Human Metapneumovirus (hMPV)

• Enanta is developing nanomolar inhibitors of human metapneumovirus, a pathogen that causes upper and lower respiratory tract infections in young children and the elderly, as well as in immunocompromised patients or those with COPD or asthma.

SARS-CoV-2

• Enanta is working to discover direct-acting antiviral drug candidates for patients infected with the novel coronavirus, SARS-CoV-2, using a combination of drug target screening and drug design. The company is focused on polymerase and protease inhibitors and is currently optimizing potent lead molecules.

Non-Alcoholic Steatohepatitis

• EDP-305, Enanta's lead farnesoid X receptor (FXR) agonist with Fast Track Designation from the FDA, is currently being evaluated in ARGON-2, a Phase 2b randomized, double-blind, placebo-controlled 72-week study of approximately 340 patients with biopsy-confirmed NASH with fibrosis, using doses of 1.5 mg and 2.0 mg. A 12-week interim analysis on a subset of patients for the company’s internal assessment is planned for mid-year 2021.
• EDP-297, Enanta’s highly potent and targeted follow-on FXR agonist also being developed for the treatment of NASH with fibrosis, is currently being evaluated in an ongoing Phase 1 randomized, double-blind, placebo-controlled, first-in-human clinical trial. Enanta expects to report safety, tolerability and pharmacokinetics data in the second quarter of 2021.
• Enanta plans to use the results of the Phase 1 study of EDP-297 and the 12-week interim analysis in ARGON-2 to prioritize both FXR agonist compounds and seek opportunities for development of one or both of them in combination with other mechanisms for NASH with fibrosis.

Webcast Information
Enanta’s presentation will take place on January 12, 2021 at 8:20 a.m. ET. A live webcast of the presentation, as well as the question and answer breakout session that follows the presentation, will be accessible by visiting the “Events and Presentations” section on the “Investors” page of Enanta’s website at www.enanta.com. A replay of the webcasts will be available following the presentation and will be archived for approximately 60 days.

ABOUT ENANTA PHARMACEUTICALS, INC.
Enanta is using its robust, chemistry-driven approach and drug discovery capabilities to become a leader in the discovery and development of small molecule drugs for the treatment of viral infections and liver diseases. Enanta’s research and development efforts have produced clinical candidates for the following disease targets: respiratory syncytial virus (RSV), hepatitis B virus (HBV) and non-alcoholic steatohepatitis (NASH). Enanta is also conducting research in human metapneumovirus (hMPV) and SARS-CoV-2 (COVID-19).

Enanta’s research and development activities are funded by royalties from hepatitis C virus (HCV) products developed under its collaboration with AbbVie. Glecaprevir, a protease inhibitor discovered by Enanta, is sold by AbbVie in numerous countries as part of its leading treatment for chronic HCV infection under the tradenames MAVYRET^® (U.S.) and MAVIRET^® (ex-U.S.) (glecaprevir/pibrentasvir). Please visit www.enanta.com for more information.

FORWARD LOOKING STATEMENTS
This press release contains forward-looking statements, including statements with respect to the prospects for advancement of Enanta’s clinical programs in RSV, HBV and NASH, as well as its discovery programs in SARS-CoV-2 and hMPV. 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: the impact of development, regulatory and marketing efforts of others with respect to competitive treatments for RSV, HBV, NASH, SARS-CoV-2 and hMPV; the discovery and development risks of Enanta’s programs in RSV, HBV, NASH, SARS-CoV-2 and hMPV; the competitive impact of development, regulatory and marketing efforts of others in those disease areas; any continuing impact of the COVID-19 pandemic on business operations and clinical trials; Enanta’s lack of clinical development experience; Enanta’s need to attract and retain senior management and key research and development 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, 2020, and any 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.

Investor and Media Contact:
Jennifer Viera
617-744-3848
jviera@enanta.com