<div id="readability-page-1"><article>SOUTH SAN FRANCISCO, Calif., May 13, 2026 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today announced topline clinical data on ABI-6250, an investigational oral hepatitis D virus (HDV) entry inhibitor, will be presented in a poster presentation at the European Association for the Study of the Liver (EASL) Congress taking place May 27-30, 2026, in Barcelona, Spain. “We are pleased to present additional Phase 1a data on ABI-6250 at EASL,” said Anuj Gaggar, MD, PhD, chief medical officer of Assembly Bio. “As the only oral entry inhibitor currently in clinical development for chronic hepatitis D, ABI-6250 is designed to offer a differentiated approach, and these data further support our plan to advance directly into a Phase 2 study by year-end.” The presentation will feature results from a randomized, blinded, Phase 1a study evaluating the safety, pharmacokinetics and pharmacodynamic activity of ABI-6250 following single- and multiple-dose administration in healthy participants. Presentation details are as follows: Title: Safety, Pharmacokinetics, and Pharmacodynamic Activity of ABI-6250, a First-in-Class Oral Hepatitis D Virus Entry Inhibitor, in Healthy Subjects: Interim Results From a Randomized, Blinded, Phase 1a Study Presenter: Edward J. Gane, MD, University of Auckland Poster Number: WED-579 Session: Viral Hepatitis B and D: New therapies, unapproved therapies or strategies Date: Wednesday, May 27, 2026 Assembly Bio intends to make the poster available on the “Events &amp; Presentations” page in the “Investors” section and on the “Publications” page in the “Pipeline” section of its website at www.assemblybio.com. ABI-6250 is an investigational product candidate that has not been approved anywhere globally, and its safety and efficacy has not been established. About Assembly Biosciences Assembly Biosciences is a biotechnology company dedicated to the development of innovative small-molecule therapeutics designed to change the path of serious viral diseases and improve the lives of patients worldwide. Led by an accomplished team of leaders in virologic drug development, Assembly Bio is committed to improving outcomes for patients struggling with the serious, chronic impacts of herpesvirus, hepatitis B virus (HBV) and HDV infections. For more information, visit assemblybio.com. Forward-Looking Statements The information in this press release contains forward-looking statements that are subject to certain risks and uncertainties that could cause actual results to materially differ. These risks and uncertainties include: Assembly Bio’s ability to realize the potential benefits of its collaboration with Gilead, including all financial aspects of the collaboration and equity investments; Assembly Bio’s ability to initiate and complete clinical studies involving its therapeutic product candidates, including studies contemplated by Assembly Bio’s collaboration with Gilead, in the currently anticipated timeframes or at all; safety and efficacy data from clinical or nonclinical studies may not warrant further development of Assembly Bio’s product candidates; clinical and nonclinical data may not differentiate Assembly Bio’s product candidates from other companies’ candidates; Assembly Bio’s ability to maintain financial resources and secure additional funding necessary to continue its research activities, clinical studies, and other business operations; potential effects of changes in government regulation; results of nonclinical studies may not be representative of disease behavior in a clinical setting and may not be predictive of the outcomes of clinical studies; and other risks identified from time to time in Assembly Bio’s reports filed with the U.S. Securities and Exchange Commission (the SEC). You are urged to consider statements that include the words may, will, would, could, should, might, believes, hopes, estimates, projects, potential, expects, plans, anticipates, intends, continues, forecast, designed, goal or the negative of those words or other comparable words to be uncertain and forward-looking. Assembly Bio intends such forward-looking statements to be covered by the safe harbor provisions contained in Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. More information about Assembly Bio’s risks and uncertainties are more fully detailed under the heading “Risk Factors” in Assembly Bio’s filings with the SEC, including its most recent Annual Report on Form 10-K, Quarterly Reports on Form 10-Q and Current Reports on Form 8-K. Except as required by law, Assembly Bio assumes no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise. Contacts: Investors: Patrick Till Meru Advisors (484) 788-8560 investor_relations@assemblybio.com Media: Sam Brown LLC Jamie Strachota (703) 819-7647 ASMBMedia@sambrown.com <img src="https://imageproxy.pbkrs.com/https://www.globenewswire.com/newsroom/ti/query-bmY9T1RjeE9EY3dNeU0zTlRrNE16WTBJekl3TWpZek9UTT0?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="1" height="1" original-src="https://imageproxy.pbkrs.com/https://www.globenewswire.com/newsroom/ti/query-bmY9T1RjeE9EY3dNeU0zTlRrNE16WTBJekl3TWpZek9UTT0"/> <img src="https://imageproxy.pbkrs.com/https://ml.globenewswire.com/media/NjNmN2U5NDktZTMzMS00ZDhjLWI1NmEtYzk0MDI4MzFjMjY4LTEwMzk3NzAtMjAyNi0wNS0xMy1lbg==/tiny/Assembly-Biosciences-Inc-.png?x-oss-process=image/auto-orient,1/interlace,1/resize,w_1440,h_1440/quality,q_95/format,jpg" width="1" height="1" original-src="https://imageproxy.pbkrs.com/https://ml.globenewswire.com/media/NjNmN2U5NDktZTMzMS00ZDhjLWI1NmEtYzk0MDI4MzFjMjY4LTEwMzk3NzAtMjAyNi0wNS0xMy1lbg==/tiny/Assembly-Biosciences-Inc-.png"/></article></div>

ASMB

Assembly Biosciences, Inc. (Nasdaq: ASMB) announced it will present topline Phase 1a data on its investigational oral hepatitis D virus entry inhibitor, ABI-6250, at the EASL Congress from May 27-30, 2026, in Barcelona. The data will support the advancement into a Phase 2 study by year-end. The presentation will cover safety, pharmacokinetics, and pharmacodynamic activity from a randomized, blinded study. ABI-6250 is currently not approved globally, and its safety and efficacy remain unestablished. For more details, visit assemblybio.com.

Assembly Biosciences to Present Topline Phase 1a Data on Hepatitis Delta Virus Entry Inhibitor ABI-6250 at the EASL Congress 2026 | ASMB Stock News