
Executive Summary Assembly Biosciences reported its second quarter 2025 financial results, highlighting significant progress in its clinical pipeline for herpes simplex virus (HSV), hepatitis B virus (HBV), and hepatitis delta virus (HDV) programs, with key data readouts anticipated in 2025 Q2 2025 Overview Assembly Biosciences reported its second quarter 2025 financial results, highlighting significant progress in its clinical pipeline for herpes simplex virus (HSV), hepatitis B virus (HBV), and hepatitis delta virus (HDV) programs, with key data readouts anticipated in 2025 - On track for proof-of-concept Phase 1b data for long-acting HSV helicase-primase inhibitor candidates, ABI-5366 and ABI-1179, no later than fall 202512 - Delivered positive topline data from Phase 1b study of ABI-4334 (HBV) and interim data from Phase 1a study of ABI-6250 (HDV), supporting target engagement2 Recent Business Highlights and Clinical Development Assembly Bio made significant clinical progress in Q2 2025, reporting positive Phase 1b data for ABI-4334 (HBV), favorable interim Phase 1a data for ABI-6250 (HDV), and initiating Phase 1b dosing for ABI-1179 (HSV), with key data readouts expected in fall 2025 Key Clinical Trial Progress Assembly Bio reported positive topline Phase 1b results for ABI-4334 in chronic HBV, demonstrating strong antiviral activity. Interim Phase 1a data for ABI-6250 in HDV showed favorable pharmacokinetics for once-daily dosing and biomarker evidence of target engagement. Dosing for ABI-1179 in its Phase 1b HSV trial was initiated, with IND clearance for US expansion - Positive topline Phase 1b data reported for ABI-4334 (HBV) met target clinical profile, showing strong antiviral activity45 - Interim Phase 1a data for ABI-6250 (HDV) in healthy volunteers showed pharmacokinetics supportive of once-daily oral dosing and biomarker data indicating engagement of its NTCP target45 - Initiated dosing in the Phase 1b portion of the ongoing Phase 1a/b trial for ABI-1179 (HSV) and received IND clearance for study expansion to US sites5 Anticipated Milestones and Events The company anticipates reporting interim efficacy, safety, and PK data from Phase 1b studies for HSV candidates ABI-5366 and ABI-1179 in fall 2025. Preclinical profiling of ABI-6250 has been accepted for oral presentation at the International HBV Meeting in September 2025 - Interim efficacy, safety, and PK data from Phase 1b studies for ABI-5366 and ABI-1179 (HSV) are expected in fall 2025, evaluating weekly (and monthly for ABI-5366) oral dosing over a 28-day period9 - An abstract describing preclinical profiling of ABI-6250 has been accepted for oral presentation at the International HBV Meeting, September 8-12, 20259 - ABI-1179 was contributed by Gilead Sciences, Inc. under the collaboration between Assembly Bio and Gilead7 Financial Performance Assembly Bio reported a reduced net loss in Q2 2025, driven by increased collaboration revenue and controlled R&D expenses, with sufficient cash to fund operations into mid-2026 Q2 2025 Financial Results Summary Assembly Bio reported a net loss of $10.2 million for Q2 2025, an improvement from $11.2 million in Q2 2024. Collaboration revenue increased, while R&D expenses slightly decreased due to reduced spending on ABI-6250. The company's cash position is projected to fund operations into mid-2026 Q2 2025 Key Financial Highlights | Metric | Q2 2025 (in millions) | Q2 2024 (in millions) | Change (YoY) | | :-------------------------------- | :-------------------- | :-------------------- | :----------- | | Cash, cash equivalents & marketable securities (as of period end) | $75.0 (June 30) | $91.0 (March 31) | -$16.0 | | Collaboration Revenue (Gilead) | $9.6 | $8.5 | +$1.1 | | Research and Development Expenses | $16.1 | $16.3 | -$0.2 | | General and Administrative Expenses | $4.6 | $4.5 | +$0.1 | | Net Loss attributable to common stockholders | $10.2 | $11.2 | -$1.0 | | Net Loss per basic and diluted share | $1.33 | $1.98 | -$0.65 | - Cash, cash equivalents and marketable securities were $75.0 million as of June 30, 2025, projected to fund operations into mid-202610 - Research and development expenses decreased primarily due to a decrease in spending on ABI-6250, which had significant preclinical and Phase 1a start-up activities in 202410 Condensed Consolidated Balance Sheets As of June 30, 2025, total assets decreased to $80.78 million from $119.17 million at December 31, 2024, primarily driven by a reduction in cash, cash equivalents, and marketable securities. Total liabilities also decreased, while stockholders' equity saw a reduction Condensed Consolidated Balance Sheets (Key Figures) | Metric (in thousands) | June 30, 2025 | December 31, 2024 | Change | | :-------------------------------- | :-------------- | :---------------- | :----- | | Cash and cash equivalents | $24,006 | $38,344 | -$14,338 | | Marketable securities | $50,974 | $73,735 | -$22,761 | | Total current assets | $77,467 | $115,503 | -$38,036 | | Total assets | $80,780 | $119,168 | -$38,388 | | Total liabilities | $62,680 | $85,809 | -$23,129 | | Total stockholders' equity | $18,100 | $33,359 | -$15,259 | Condensed Consolidated Statements of Operations and Comprehensive Loss For the three months ended June 30, 2025, collaboration revenue increased by 12.8% year-over-year, while total operating expenses remained relatively flat. The net loss decreased to $10.2 million from $11.2 million in the prior year period, and net loss per share improved significantly Condensed Consolidated Statements of Operations (Q2 2025 vs Q2 2024) | Metric (in thousands) | Three Months Ended June 30, 2025 | Three Months Ended June 30, 2024 | Change (YoY) | | :-------------------------------- | :------------------------------- | :------------------------------- | :----------- | | Collaboration revenue | $9,626 | $8,533 | +$1,093 (12.8%) | | Research and development expenses | $16,125 | $16,259 | -$134 (-0.8%) | | General and administrative expenses | $4,594 | $4,477 | +$117 (2.6%) | | Total operating expenses | $20,719 | $20,736 | -$17 (-0.1%) | | Loss from operations | $(11,093) | $(12,203) | +$1,110 | | Net loss | $(10,198) | $(11,152) | +$954 | | Net loss per share, basic and diluted | $(1.33) | $(1.98) | +$0.65 | Condensed Consolidated Statements of Operations (Six Months Ended June 30, 2025 vs 2024) | Metric (in thousands) | Six Months Ended June 30, 2025 | Six Months Ended June 30, 2024 | Change (YoY) | | :-------------------------------- | :----------------------------- | :----------------------------- | :----------- | | Collaboration revenue | $19,045 | $14,318 | +$4,727 (33.0%) | | Research and development expenses | $30,976 | $28,138 | +$2,838 (10.1%) | | General and administrative expenses | $9,103 | $9,112 | -$9 (-0.1%) | | Total operating expenses | $40,079 | $37,250 | +$2,829 (7.6%) | | Loss from operations | $(21,034) | $(22,932) | +$1,898 | | Net loss | $(19,016) | $(20,229) | +$1,213 | | Net loss per share, basic and diluted | $(2.51) | $(3.64) | +$1.13 | Additional Information This section provides an overview of Assembly Biosciences, its therapeutic focus, forward-looking statement disclaimers, and contact information About Assembly Biosciences Assembly Biosciences is a biotechnology company focused on developing innovative small-molecule therapeutics to address serious viral diseases, specifically herpesvirus, hepatitis B virus (HBV), and hepatitis delta virus (HDV) infections - Assembly Biosciences is a biotechnology company developing innovative small-molecule therapeutics for serious viral diseases12 - The company is committed to improving outcomes for patients with herpesvirus, hepatitis B virus (HBV), and hepatitis delta virus (HDV) infections12 Forward-Looking Statements This section contains standard forward-looking statements, highlighting various risks and uncertainties that could cause actual results to differ materially. These include the company's ability to maintain financial resources, realize benefits from its collaboration with Gilead, initiate and complete clinical studies, and the potential impact of regulatory changes - Forward-looking statements are subject to risks and uncertainties, including the ability to maintain financial resources, secure additional funding, and realize benefits from the Gilead collaboration13 - Risks also include the ability to initiate and complete clinical studies in anticipated timeframes, and that safety and efficacy data may not warrant further development or differentiate product candidates13 - Such statements are intended to be covered by the safe harbor provisions of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 193413 Contacts This section provides contact information for investor relations and media inquiries - Investor and Corporate Contact: Shannon Ryan, SVP, Investor Relations, Corporate Affairs and Alliance Management, (415) 738-2992, investor_relations@assemblybio.com14 - Media Contact: Alyssa Kuciunas, Sam Brown Healthcare Communications, (331) 481-3751, ASMBMedia@sambrown.com14