Vebicorvir

Clinical trial application clearances received for a Phase 1a/1b trial for ABI-5366 targeting recurrent genital herpes, and a Phase 1b trial for ABI-4334 in chronic HBV infection; both studies on track to initiate by mid-2024 ABI-5366 interim Phase 1a first-in-human data expected in Q3 2024 and ABI-4334 interim Phase 1b data expected by end of year SOUTH SAN FRANCISCO, Calif., May 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 highlights for the first quarter ended March 31, 2024. “We are pleased that we now have regulatory clearance to initiate trials evaluating our promising investigational therapies ABI-5366 and ABI-4334 and look forward to sharing interim data from these studies later this year,” said Jason Okazaki, chief executive officer and president of Assembly Bio. “These clearances are a significant step toward our goal of reaching key clinical inflection points for multiple programs in our antiviral pipeline by year end. Our continued clinical progress reflects the strength and agility of our highly experienced team and our singular focus of improving treatment options for those living with serious viral diseases.” First Quarter 2024 and Recent Highlights Two clinical trial applications received clearance to proceed: ABI-5366, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate, for initiation of Phase 1a/1b clinical studies in both healthy volunteers and in individuals with recurrent genital herpesABI-4334, a next-generation, highly potent capsid assembly modulator candidate, for initiation of a Phase 1b study in individuals with chronic hepatitis B virus (HBV) infection An abstract highlighting preclinical data for ABI-6250, an oral, small molecule HBV/hepatitis delta virus (HDV) entry inhibitor candidate, has been accepted for poster presentation at the European Association for the Study of the Liver (EASL) CongressTM 2024, June 5-8, 2024 Anticipated 2024 Milestones ABI-5366 and ABI-4334 studies expected to initiate by mid-2024: ABI-5366 Phase 1a interim clinical data expected in Q3 2024 and interim Phase 1b data expected in the first half of 2025ABI-4334 Phase 1b interim clinical data expected by the end of 2024 Two additional candidates are anticipated to enter the clinic by the end of 2024: ABI-1179, a long-acting HSV helicase-primase inhibitor contributed by Gilead Sciences, Inc. (Gilead) under the collaboration between Assembly Bio and GileadABI-6250, a small molecule orally-bioavailable HDV entry inhibitor First Quarter 2024 Financial Results Cash, cash equivalents and marketable securities were $113.0 million as of March 31, 2024, compared to $130.2 million as of December 31, 2023. Assembly Bio’s cash position is projected to fund operations into the second half of 2025.Revenues from collaborative research were $5.8 million for the three months ended March 31, 2024. There was no revenue recognized for the same period in 2023. Revenue for the three months ended March 31, 2024 consists of amounts recognized under the collaboration with Gilead.Research and development expenses were $11.9 million for the three months ended March 31, 2024, compared to $14.5 million for the same period in 2023. Increased expenses related to the development of ABI-1179 and ABI-6250 were more than offset by savings from the discontinuation of ABI-H3733 and vebicorvir as well as reduced employee and contractor-related expenses.General and administrative expenses were $4.6 million for the three months ended March 31, 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 $9.1 million, or $1.66 per basic and diluted share, for the three months ended March 31, 2024, compared to $19.0 million, or $4.46 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) 338-4752  ASMBMedia@sambrown.com ASSEMBLY BIOSCIENCES, INC. CONDENSED CONSOLIDATED BALANCE SHEETS (In thousands except for share amounts and par value) March 31, December 31, 2024 2023 (Unaudited) ASSETS Current assets Cash and cash equivalents $18,749 $19,841 Marketable securities 94,227 110,406 Accounts receivable from collaboration 43 43 Prepaid expenses and other current assets 4,149 3,497 Total current assets 117,168 133,787 Property and equipment, net 367 385 Operating lease right-of-use assets 2,036 2,339 Other assets 312 312 Total assets $ 119,883 $ 136,823 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities Accounts payable $727 $461 Accrued research and development expenses 2,059 885 Other accrued expenses 2,051 5,744 Deferred revenue from a related party - short-term 32,771 30,915 Operating lease liabilities - short-term 1,145 1,220 Total current liabilities 38,753 39,225 Deferred revenue from a related party - long-term 47,738 55,379 Operating lease liabilities - long-term 791 1,122 Total liabilities 87,282 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 March 31, 2024 and December 31, 2023; 5,482,752 shares issued and outstanding as of March 31, 2024 and December 31, 2023 5 5 Additional paid-in capital 827,660 826,921 Accumulated other comprehensive loss (239) (81) Accumulated deficit (794,825) (785,748) Total stockholders' equity 32,601 41,097 Total liabilities and stockholders' equity $ 119,883 $ 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 March 31, 2024 2023 Collaboration revenue from a related party $5,785 $— Operating expenses Research and development 11,879 14,547 General and administrative 4,635 5,012 Total operating expenses 16,514 19,559 Loss from operations (10,729) (19,559) Other income Interest and other income, net 1,652 609 Total other income 1,652 609 Net loss $ (9,077) $ (18,950) Other comprehensive loss Unrealized (loss) gain on marketable securities (158) 290 Comprehensive loss $ (9,235) $ (18,660) Net loss per share, basic and diluted $(1.66) $(4.46) Weighted average common shares outstanding, basic and diluted 5,483,313 4,251,037

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, Inc. partnership supports advancement and strengthening of antiviral pipeline targeting serious viral diseases SOUTH SAN FRANCISCO, Calif., March 28, 2024 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today reported financial results and recent highlights for the fourth quarter and year ended December 31, 2023. “Our progress in 2023 demonstrated our capacity to drive our expanded antiviral pipeline forward and our commitment to individuals suffering from life-impacting viral diseases,” said Jason Okazaki, chief executive officer and president of Assembly Bio. “With our long-term partnership in place with Gilead and the addition of Dr. Anuj Gaggar to our management team as CMO, we are well-positioned to make critical progress clinically across multiple programs in 2024 and look forward to sharing preliminary data on 5366 and 4334 later this year.” Fourth Quarter 2023 and Recent Highlights Entered a long-term partnership with Gilead to advance discovery and development of novel antiviral therapies Strengthened the leadership team with the naming of Anuj Gaggar, MD, PhD, as chief medical officer Filed a clinical trial application for ABI-5366 to support initiation of Phase 1a/1b clinical studies Anticipated Milestones and Events By mid-year 2024: ABI-5366, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor targeting recurrent genital herpes, is expected to enter a Phase 1a/1b study ABI-4334, a next-generation, highly potent capsid assembly modulator, is anticipated to enter a Phase 1b study in individuals with chronic hepatitis B virus infection Q3 2024: Interim clinical data from the ABI-5366 Phase 1a study portion expected to be available By the end of 2024: Interim clinical data from the ABI-4334 Phase 1b study expected to be available The Phase 1b portion of the ABI-5366 study, in individuals with recurrent genital herpes, is anticipated to be underway Two additional candidates are anticipated to enter the clinic: ABI-1179, a long-acting HSV helicase-primase inhibitor contributed by Gilead under the collaboration between Assembly Bio and Gilead ABI-6250, a small molecule orally-bioavailable hepatitis delta virus entry inhibitor First half 2025: Interim clinical data from the Phase 1b portion of the ABI-5366 study expected to be available Fourth Quarter 2023 and Year End Financial Results Cash, cash equivalents and marketable securities were $130.2 million as of December 31, 2023, compared to $46.2 million as of September 30, 2023, and $91.6 million as of the year ended December 31, 2022. The company’s cash position is projected to fund operations into the second half of 2025. Revenues from collaborative research were $7.2 million for the year ended December 31, 2023. There was no revenue recognized for the same period in 2022. Revenue for the year ended December 31, 2023, consists of $4.4 million recognized under the collaboration with Gilead and the remaining deferred revenue balance of $2.7 million under the collaboration agreement with BeiGene following Assembly Bio’s decision to discontinue further development of ABI-H3733 in conjunction with entering into the Gilead collaboration, following the previous prioritization of ABI-4334 over ABI-H3733. Research and development expenses were $48.9 million for the year ended December 31, 2023, compared to $70.0 million in 2022. The decrease is due to completion of the clinical trials for ABI-H3733 and ABI-4334, discontinued development of vebicorvir and ABI-H2158, and decreases in employee and contractor-related expenses. General and administrative expenses were $22.9 million for the year ended December 31, 2023, compared to $24.1 million in 2022. The decrease is due to overall cost-saving initiatives. Net loss attributable to common stockholders was $61.2 million, or $13.38 per basic and diluted share, for the year ended December 31, 2023, compared to $93.1 million, or $23.08 per basic and diluted share in 2022. 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 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 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 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) 338-4752  ASMBMedia@sambrown.com ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED BALANCE SHEETS (In thousands except for share amounts and par value) As of December 31, 2023 2022 ASSETS Current assets Cash and cash equivalents $ 19,841 $ 52,418 Marketable securities 110,406 39,192 Accounts receivable from collaboration 43 944 Prepaid expenses and other current assets 3,497 4,413 Total current assets 133,787 96,967 Property and equipment, net 385 743 Operating lease right-of-use assets 2,339 3,195 Other assets 312 889 Total assets $ 136,823 $ 101,794 LIABILITIES AND STOCKHOLDERS' EQUITY Current liabilities Accounts payable $ 461 $ 2,493 Accrued research and development expenses 885 3,122 Other accrued expenses 5,744 7,317 Deferred revenue - short-term ($30,915 and $− to a related party) 30,915 — Operating lease liabilities - short-term 1,220 3,364 Total current liabilities 39,225 16,296 Deferred revenue - long-term ($55,379 and $− to a related party) 55,379 2,733 Operating lease liabilities - long-term 1,122 101 Total liabilities 95,726 19,130 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 December 31, 2023 and December 31, 2022; 5,482,752 and 4,074,552 shares issued and outstanding as of December 31, 2023 and December 31, 2022, respectively 5 4 Additional paid-in capital 826,921 807,983 Accumulated other comprehensive loss (81 ) (803 ) Accumulated deficit (785,748 ) (724,520 ) Total stockholders' equity 41,097 82,664 Total liabilities and stockholders' equity $ 136,823 $ 101,794 ASSEMBLY BIOSCIENCES, INC. CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (In thousands except for share and per share amounts) Year Ended December 31, 2023 2022 Collaboration revenue ($4,430 and $− from a related party) $ 7,163 $ — Operating expenses Research and development 48,900 69,980 General and administrative 22,909 24,134 Total operating expenses 71,809 94,114 Loss from operations (64,646 ) (94,114 ) Other income Interest and other income, net 3,451 1,022 Total other income 3,451 1,022 Loss before income taxes (61,195 ) (93,092 ) Income tax expense (33 ) — Net loss $ (61,228 ) $ (93,092 ) Other comprehensive loss Unrealized gain (loss) on marketable securities 722 (384 ) Comprehensive loss $ (60,506 ) $ (93,476 ) Net loss per share, basic and diluted $ (13.38 ) $ (23.08 ) Weighted average common shares outstanding, basic and diluted 4,577,371 4,034,105