ABI-1179

Dosing initiated in healthy participants in Phase 1a/b trial for ABI-5366 targeting recurrent genital herpes, with interim Phase 1a first-in-human data expected in Q3 2024 and interim Phase 1b data in participants with recurrent genital herpes expected in first half of 2025Dosing initiated in Phase 1b trial for ABI-4334 in participants with chronic HBV infection, with interim Phase 1b data expected by end of yearTwo additional pipeline candidates, ABI-1179 and ABI-6250, anticipated to enter clinic by end of year SOUTH SAN FRANCISCO, Calif., Aug. 08, 2024 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today reported financial results and recent updates for the second quarter ended June 30, 2024. “Entering the second half of the year, I’m incredibly proud of our team’s accomplishments on our path to delivering novel therapeutics for individuals living with serious viral diseases,” said Jason Okazaki, chief executive officer and president of Assembly Bio. “We are rapidly progressing toward key inflection points for our clinical development programs and remain on track with the data sets we plan to deliver in 2024. Specifically, in the third quarter, we look forward to sharing interim Phase 1a data for ABI-5366 in healthy participants. The pharmacokinetic data in this study will enable us to assess ABI-5366's ability to reach the target concentrations we have established for antiviral efficacy and to support our once-weekly oral dosing profile, while also informing dose selection in the Phase 1b part of the study in participants with recurrent genital herpes.” Second Quarter 2024 and Recent Highlights First participants were dosed in two clinical trials: The Phase 1a portion of a Phase 1a/b clinical study of ABI-5366, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate; the Phase 1a portion in healthy participants and the Phase 1b portion to be conducted in participants with recurrent genital herpesA Phase 1b study of ABI-4334, a next-generation, highly potent capsid assembly modulator candidate, in participants with chronic hepatitis B virus (HBV) infection Scientific conference presentations highlighted: Preclinical data for ABI-5366 (poster presentation) and ABI-1179 (poster and oral presentation) featured at the International Herpesvirus Workshop held July 13-17, 2024. ABI-1179 is the long-acting HSV helicase-primase inhibitor candidate contributed by Gilead Sciences, Inc. (Gilead) under the collaboration between Assembly Bio and GileadPreclinical data for ABI-6250, an oral, small molecule HBV/hepatitis delta virus (HDV) entry inhibitor candidate, featured in a poster presentation at the European Association for the Study of the Liver (EASL) Congress™ 2024 held June 5-8, 2024Preclinical data for ABI-6250 featured in an oral presentation at the Science of HBV Cure Meeting 2024 held July 26-27, 2024 Strengthened balance sheet with equity investments that resulted in aggregate gross proceeds to Assembly Bio of approximately $12.6 million, supporting advancement of antiviral portfolio and extending cash runway into Q1 2026 Upcoming Anticipated Milestones ABI-5366 Phase 1a interim clinical data in healthy participants expected in Q3 2024 and interim Phase 1b data in participants with recurrent genital herpes expected in the first half of 2025ABI-4334 Phase 1b interim clinical data expected by the end of 2024Two additional candidates, ABI-1179 and ABI-6250, are anticipated to enter the clinic by the end of 2024 Upcoming Conferences Abstract highlighting preclinical data for ABI-6250 accepted for poster presentation at the International HBV Meeting taking place September 11-15, 2024, in Chicago Second Quarter 2024 Financial Results Cash, cash equivalents and marketable securities were $109.2 million as of June 30, 2024, compared to $113.0 million as of March 31, 2024. Assembly Bio’s cash position is projected to fund operations into Q1 2026.Revenue from collaborative research was $8.5 million for the three months ended June 30, 2024. There was no revenue recognized for the same period in 2023. Revenue for the three months ended June 30, 2024, consists of amounts recognized under the collaboration with Gilead.Research and development expenses were $16.3 million for the three months ended June 30, 2024, compared to $12.5 million for the same period in 2023. The increase is attributable to having more candidates in development in 2024.General and administrative expenses were $4.5 million for the three months ended June 30, 2024, compared to $5.0 million for the same period in 2023. The decrease is primarily due to a decrease in non-cash stock-based compensation expense.Net loss attributable to common stockholders was $11.2 million, or $1.98 per basic and diluted share, for the three months ended June 30, 2024, compared to $16.9 million, or $3.88 per basic and diluted share, for the same period in 2023. The investigational products and investigational product candidates referenced here have not been approved anywhere globally, and their safety and efficacy have not been established. About Assembly BiosciencesAssembly 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 hepatitis delta virus (HDV) infections. For more information, visit assemblybio.com. Forward-Looking StatementsThe 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 Sciences, Inc., 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 presented at conferences may not differentiate Assembly Bio’s product candidates from other companies’ candidates; 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 Investor and Corporate: Shannon Ryan SVP, Investor Relations, Corporate Affairs and Alliance Management (415) 738-2992 investor_relations@assemblybio.com Media: Sam Brown Inc.Hannah Hurdle(805) 338-4752ASMBMedia@sambrown.com ASSEMBLY BIOSCIENCES, INC.CONDENSED CONSOLIDATED BALANCE SHEETS(In thousands except for share amounts and par value) June 30, December 31, 2024 2023 (Unaudited) ASSETS Current assets Cash and cash equivalents$19,208 $19,841 Marketable securities90,011 110,406 Accounts receivable from collaboration— 43 Prepaid expenses and other current assets3,712 3,497 Total current assets112,931 133,787 Property and equipment, net349 385 Operating lease right-of-use assets1,731 2,339 Other assets312 312 Total assets$115,323 $136,823 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities Accounts payable$801 $461 Accrued research and development expenses2,531 885 Other accrued expenses3,587 5,744 Deferred revenue from a related party - short-term33,060 30,915 Operating lease liabilities - short-term1,295 1,220 Total current liabilities41,274 39,225 Deferred revenue from a related party - long-term38,916 55,379 Operating lease liabilities - long-term451 1,122 Total liabilities80,641 95,726 Commitments and contingencies Stockholders' equity Preferred stock, $0.001 par value; 5,000,000 shares authorized; no shares issued or outstanding— — Common stock, $0.001 par value; 150,000,000 shares authorized as of June 30, 2024 and December 31, 2023; 6,345,561 and 5,482,752 shares issued and outstanding as of June 30, 2024 and December 31, 2023, respectively6 5 Additional paid-in capital840,946 826,921 Accumulated other comprehensive loss(293) (81)Accumulated deficit(805,977) (785,748)Total stockholders' equity34,682 41,097 Total liabilities and stockholders' equity$115,323 $136,823 ASSEMBLY BIOSCIENCES, INC.CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS(In thousands except for share and per share amounts)(Unaudited) Three Months Ended June 30, Six Months Ended June 30, 2024 2023 2024 2023 Collaboration revenue from a related party$8,533 $— $14,318 $— Operating expenses Research and development16,259 12,523 28,138 27,070 General and administrative4,477 4,965 9,112 9,977 Total operating expenses20,736 17,488 37,250 37,047 Loss from operations(12,203) (17,488) (22,932) (37,047) Other income Interest and other income, net1,457 592 3,109 1,201 Total other income1,457 592 3,109 1,201 Loss before income taxes(10,746) (16,896) (19,823) (35,846) Income tax expense406 — 406 — Net loss$(11,152) $(16,896) $(20,229) $(35,846) Other comprehensive loss Unrealized (loss) gain on marketable securities(54) 188 (212) 478 Comprehensive loss$(11,206) $(16,708) $(20,441) $(35,368) Net loss per share, basic and diluted$(1.98) $(3.88) $(3.64) $(8.33)Weighted average common shares outstanding, basic and diluted5,642,752 4,355,007 5,563,033 4,303,244

– Data from both ABI-5366 and ABI-1179, novel long-acting helicase-primase inhibitor candidates for recurrent genital herpes, to be presented – – Poster presentation highlights key preclinical data from ABI-5366 supporting its entry into ongoing Phase 1a/b clinical trials – – Oral and poster presentations feature first data presented from ABI-1179, expected to enter the clinic by the end of 2024 – SOUTH SAN FRANCISCO, Calif., July 15, 2024 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today announced new preclinical data from its investigational herpes simplex virus (HSV) portfolio featured in three presentations at the International Herpesvirus Workshop (IHW), taking place July 13-17, 2024, in Portland, Ore. “We are excited to present promising data from our HSV helicase-primase inhibitor candidates ABI-5366 and ABI-1179, which we are rapidly progressing to deliver on our mission of offering new, effective treatments for people living with chronic viral diseases,” said Anuj Gaggar, MD, PhD, chief medical officer of Assembly Bio. “Current treatments for recurrent genital herpes often fall short in fully managing symptoms and preventing recurrences, and we are pleased with the potential of our HSV candidates to provide a different approach, as highlighted in the data presented at IHW. We continue to advance these candidates and look forward to sharing further updates with the herpesvirus community, including interim ABI-5366 Phase 1a first-in-human data expected in the third quarter of this year.” Approximately 50% of individuals with initial symptomatic genital herpes infection have three or more recurrences per year, including over four million people in the United States and France, Germany, Italy and Spain (collectively, the EU4), and the United Kingdom. While genital herpes can be caused by either HSV type 1 (HSV-1) or HSV type 2 (HSV-2), recurrences are more likely to be experienced by individuals infected by HSV-2. The current standard of care for recurrent genital herpes are nucleoside analogs; however, these are only partially effective in preventing recurrences. Assembly Bio’s HSV antiviral candidates target the HSV helicase-primase complex, an essential HSV enzyme complex with no host equivalent, and are designed for long-acting administration. A poster entitled “The Helicase-Primase Inhibitor ABI-5366 Is a Novel, Potent, Long-Acting Inhibitor for the Treatment of Recurrent Genital Herpes” highlights preclinical data that supported ABI-5366’s entry into Phase 1 clinical evaluation. Results demonstrated that ABI-5366 showed low nanomolar activity against both HSV-1 and HSV-2, including broad activity against HSV clinical isolates, and specificity for HSV. ABI-5366 was shown to be generally non-toxic across a variety of cell types with no off-target effects observed in vitro or in vivo, including no activity against carbonic anhydrase esterases. Further, a favorable in vivo safety profile of ABI-5366 was observed in 28-day oral toxicity studies in two species, and pharmacokinetic (PK) studies evaluating ABI-5366 when administered orally or intramuscularly demonstrated long-acting potential for this compound. The Phase 1a/b study for ABI-5366 was initiated in May 2024 and is currently enrolling; interim Phase 1a data are expected in Q3 2024 and interim Phase 1b data are expected in the first half of 2025. Additionally, an oral and poster presentation entitled “Preclinical Characterization of ABI-1179, a Potent Helicase Primase Inhibitor for the Treatment of Recurrent Genital Herpes” features preclinical data from ABI-1179, a structurally distinct, long-acting helicase-primase inhibitor candidate, licensed from Gilead Sciences, Inc. (Gilead) under the collaboration between Assembly Bio and Gilead. ABI-1179 has demonstrated low nanomolar activity across HSV-1 and HSV-2 lab strains and clinical isolates, including acyclovir-resistant isolates. In resistance selection studies, ABI-1179 displayed a higher barrier to resistance development than acyclovir. Furthermore, ABI-1179 demonstrated antiviral activity against some HSV-2 strains harboring mutations known to confer resistance to other helicase-primase inhibitors. In a preclinical study, ABI-1179 demonstrated a favorable PK profile that supports the evaluation of once-weekly oral dosing. Further, in a preclinical model of recurrent HSV infection, ABI-1179 significantly reduced the development of recurrent lesions. Assembly Bio expects to initiate a Phase 1a/b first-in-human study of ABI-1179 by the end of 2024. Assembly Bio intends to make the presentations available on the “Events & Presentations” page in the “Investors” section of its website at www.assemblybio.com. The investigational product candidates ABI-5366 and ABI-1179 have not been approved anywhere globally, and their safety and efficacy have 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 hepatitis delta virus (HDV) infections. For more information, visit assemblybio.com. Forward-Looking StatementsThe 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 Sciences, Inc., 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 presented at conferences may not differentiate Assembly Bio’s product candidates from other companies’ candidates; 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. ContactsInvestor and Corporate:Shannon RyanSVP, Investor Relations, Corporate Affairs and Alliance Management(415) 738-2992investor_relations@assemblybio.com Media:Sam Brown Inc.Hannah Hurdle(805) 338-4752ASMBMedia@sambrown.com