ABI-4334

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

— Funding supports advancement of antiviral portfolio, including four candidates in clinical development, and extends cash runway into Q1 2026 — — Anticipated near term interim data read outs include ABI-5366 Phase 1a in 3Q24 and Phase 1b in 1H25, and ABI-4334 Phase 1b by end of 2024 — SOUTH SAN FRANCISCO, Calif., June 17, 2024 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (“Assembly Bio”) (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today announced that it has closed the issuance of shares of its common stock and warrants to Armistice Capital LLC (“Armistice Capital”), a healthcare-focused institutional investor, and Gilead Sciences, Inc. (“Gilead”), in separate equity financings that have resulted in aggregate gross proceeds to Assembly Bio of approximately $12.6 million, before deducting expenses. The sale of common stock to Gilead maintains Gilead’s ownership of 19.9 percent of the outstanding voting stock of Assembly Bio as of the date of closing pursuant to the terms of the Investor Rights Agreement entered into between Assembly Bio and Gilead in October 2023 (the “Investor Rights Agreement”). Assembly Bio and Gilead have also agreed to extend the time period to satisfy certain conditions related to Assembly Bio’s right to require Gilead to increase its ownership from 19.9 percent up to 29.9 percent of Assembly Bio’s outstanding voting stock at a premium. “The Armistice and Gilead investments strengthen our balance sheet as we look to deliver important interim clinical data readouts expected by the end of the year and continue to advance our novel pipeline,” said Jason Okazaki, chief executive officer and president of Assembly Bio. “In addition, the amendment of our equity agreement terms with Gilead reflects our companies’ shared commitment to the advancement of our collaboration candidates in the coming years, with four candidates expected to be in clinic this year.” Assembly Bio sold 634,500 shares of common stock and warrants to purchase up to 634,500 shares to Armistice Capital, and sold 179,500 shares of common stock and warrants to purchase up to 179,500 shares to Gilead, in each case, at a combined price of $15.46 per share of common stock and accompanying warrant. The warrants have an exercise price of $17.00 per share of common stock, will be immediately exercisable and will expire on June 18, 2029. Assembly Bio currently expects to use the net proceeds from the equity financings for general corporate purposes. The shares of common stock and warrants sold to Armistice Capital were issued in a registered direct offering pursuant to Assembly Bio’s existing effective shelf registration statement on Form S-3 (File 333-270760) that was originally filed on March 22, 2023, and declared effective by the Securities and Exchange Commission (“SEC”) on April 14, 2023. The shares and warrants sold to Gilead were sold in a private placement. The securities sold to Gilead have not been registered under the Securities Act of 1933, as amended, or applicable state securities laws, and may not be offered or sold in the United States except pursuant to an effective registration statement or an applicable exemption from the registration requirements. Pursuant to the Investor Rights Agreement, as amended, Assembly Bio has agreed to registration statement with the Securities and Exchange Commission registering the resale of the shares of common stock issued to Gilead and the shares of common stock issuable upon exercise of the warrants issued to Gilead. This press release shall not constitute an offer to sell or the solicitation of an offer to buy any securities described herein, nor shall there be any sale of these securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to the registration or qualification under the securities laws of any such state or jurisdiction. 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. 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 forward-looking statements include all statements other than historical fact, including, without limitation, statements regarding the equity financings and the use of proceeds therefrom; and statements regarding the Company’s future performance and clinical development plans. 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 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. 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 sryan@assemblybio.com Media: Sam Brown Inc. Hannah Hurdle (805) 338-4752 ASMBMedia@sambrown.com