Exhibit 99.1 Assembly Biosciences Reports Fourth Quarter and Year End 2023 Financial Results and Recent Highlights • Four candidates planned to be in clinical development in 2024 with interim data from two studies anticipated by year end • Clinical development timelines accelerated for ABI-5366; now anticipating interim data from Phase 1a available in 3Q2024, initiation of Phase 1b in individuals with recurrent genital herpes by end of 2024 and interim Phase 1b data available in 1H2025 • Gilead Sciences, In ...

– Assembly Bio common stock expected to begin trading on a split-adjusted basis on February 12, 2024 – SOUTH SAN FRANCISCO, Calif., Feb. 08, 2024 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (NASDAQ:ASMB), a biotechnology company developing innovative antiviral therapeutics targeting serious viral diseases, today announced that it expects a 1-for-12 reverse stock split of its outstanding shares of common stock will be effective as of February 9, 2024. The company anticipates that its common stock will beg ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________to___________. Commission file number: 001-35005 ASSEMBLY BIOSCIENCES, INC. (Exact name of Registrant as specified in its charter) Delaware 20-8729264 (St ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________to___________. Commission file number: 001-35005 ASSEMBLY BIOSCIENCES, INC. (Exact name of Registrant as specified in its charter) Delaware 20-8729264 (State o ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from ___________to___________. Commission file number: 001-35005 ASSEMBLY BIOSCIENCES, INC. (Exact name of Registrant as specified in its charter) Delaware 20-8729264 (State ...

Clinical Development - The biopharmaceutical company is advancing clinical candidates targeting chronic hepatitis B virus (HBV) and hepatitis delta virus (HDV), with a focus on improving patient outcomes and developing curative therapies[217]. - The company has paused the development of its first-generation core inhibitor, VBR, due to insufficient efficacy data and is now prioritizing next-generation core inhibitors, ABI-H3733 and ABI-4334[218][236]. - In the Phase 1b trial of ABI-H3733, six of eight patients in the 50 mg cohort achieved HBV DNA levels below the lower limit of quantification (<LLOQ) within 21 days, with a mean decline of approximately 3.1 logs[233]. - ABI-H4334 has demonstrated a best-in-class preclinical profile with single-digit nanomolar potency against both the production of new virus and the formation of cccDNA[239]. - The company initiated a Phase 1a clinical study of ABI-H4334 in October 2022, with interim data showing mild to moderate treatment-emergent adverse events and no significant ECG abnormalities reported[240]. - The company aims to develop oral small molecule entry inhibitors for HDV, which currently relies on off-label treatments that require complex administration[222]. - The strategic focus includes advancing research activities on HBV/HDV entry inhibitors and long-acting HSV-2 helicase inhibitors targeting high-recurrence genital herpes[218]. - The company announced a research program for a novel oral small molecule entry inhibitor targeting HBV and HDV, aiming to nominate a product candidate for development in 2023[242]. - The investigational IFNAR agonist program aims to selectively activate the IFN-α pathway in the liver, improving tolerability compared to existing subcutaneous therapies[243]. - The company has identified an opportunity to develop an oral pan-herpes NNPI for transplant-associated herpesvirus infections, simplifying treatment for patients[250]. - The company’s herpesvirus programs target high-recurrence genital herpes and transplant-associated herpesviruses, addressing significant unmet medical needs[246]. Financial Performance - As of December 31, 2022, the company reported an accumulated deficit of $724.5 million, with expectations of continued losses as product candidates are developed[252]. - The company has had no revenue from product sales since inception and has funded operations primarily through debt and equity financings[251]. - Collaboration revenue for the year ended December 31, 2022 was $0, a decrease of 100% compared to $6.3 million in 2021, which was recognized upon discontinuing development of product 2158[273]. - Research and development expenses increased to $70.0 million in 2022 from $68.5 million in 2021, reflecting a $1.5 million increase driven by higher employee and contractor-related expenses[276]. - General and administrative expenses decreased by 16% to $24.1 million in 2022 from $28.8 million in 2021, primarily due to reductions in professional fees and stock-based compensation[278]. - The impairment of goodwill and indefinite-lived intangible assets was $0 in 2022, compared to $41.6 million in 2021, reflecting a significant reduction in impairment charges[279]. - Interest and other income increased by 238% to $1.0 million in 2022 from $0.3 million in 2021, mainly due to higher interest income from marketable securities[280]. - The company raised an aggregate of $605.0 million in net proceeds from public offerings and private placements from inception to December 31, 2022[284]. - Future operating expenses are expected to decrease due to cost savings from a strategic reorganization plan implemented in July 2022, but substantial additional funding will still be required[285]. - The company has no FDA-approved products and has generated operating losses since its incorporation in October 2005, relying on additional financings to achieve business objectives[289]. Operational Changes - The company implemented a strategic restructuring plan in July 2022, resulting in a workforce reduction of 30 employees, leaving approximately 70 employees[218]. - Contractual obligations include operating lease obligations totaling $3.5 million as of December 31, 2022, with $3.4 million being short-term[286]. - Net cash used in operating activities was $84.5 million for the year ended December 31, 2022, primarily due to a net loss of $93.1 million[294]. - Net cash provided by investing activities for the year ended December 31, 2022 was $90.6 million, mainly from proceeds of $89.2 million from sales and maturities of marketable securities[296]. - Net cash provided by financing activities for the year ended December 31, 2022 was $0.6 million, resulting from the sale of 300,827 shares of common stock[297]. - The company reported a net cash used in operating activities of $93.4 million for the year ended December 31, 2021, due to a net loss of $129.9 million[294]. - The company had a net cash provided by investing activities of $26.5 million for the year ended December 31, 2021[296]. - The company expects to finance cash needs through equity offerings, debt financings, collaborations, strategic alliances, and licensing arrangements[290]. - If additional funds are not raised, the company may need to delay or terminate product development efforts[291]. - The company does not have any committed external source of funds, which may lead to dilution of stockholder ownership if additional capital is raised[290]. Asset Impairment - The company recognized a goodwill impairment charge of $12.6 million in 2021 due to a decline in market capitalization and unfavorable clinical trial results[263]. - The indefinite-lived intangible asset related to in-process research and development was fully impaired, reflecting the challenges in advancing certain projects[266]. - As of December 31, 2022, the company had an accumulated deficit of $724.5 million primarily due to research and development and general administrative expenses[272]. Internal Controls - The company’s internal control over financial reporting was deemed effective as of December 31, 2022[300].