Company Description
Assembly Biosciences, Inc. (Nasdaq: ASMB) is a biotechnology company focused on developing small‑molecule therapeutics for serious viral diseases. According to multiple company disclosures, Assembly Biosciences (often referred to as Assembly Bio) is dedicated to creating medicines intended to change the course of chronic viral infections and improve the lives of patients affected by these conditions. The company emphasizes programs in herpesviruses and viral hepatitis, including hepatitis B virus (HBV) and hepatitis delta virus (HDV).
Assembly Biosciences is described in its public communications as being led by an experienced team in virologic drug development. Across its news releases and SEC filings, the company consistently characterizes its approach as centered on innovative small‑molecule antiviral therapeutics targeting key steps in viral lifecycles. Its common stock is listed on The Nasdaq Global Select Market under the ticker symbol ASMB, as indicated in the company’s Form 8‑K filings.
Focus on serious viral diseases
In repeated “About Assembly Biosciences” statements contained in press releases and financial updates, the company states that it is committed to improving outcomes for patients dealing with the serious, chronic impacts of herpesvirus, hepatitis B virus (HBV) and hepatitis delta virus (HDV) infections. These conditions are highlighted as areas of significant unmet medical need, and Assembly Bio’s pipeline is organized around these disease areas.
Publicly reported programs include investigational candidates for:
- Recurrent genital herpes, caused by herpes simplex virus (HSV), where the company is advancing long‑acting helicase‑primase inhibitor candidates ABI‑5366 and ABI‑1179 in Phase 1b clinical studies.
- Chronic hepatitis B virus infection, where Assembly Bio is developing ABI‑4334, described as a next‑generation, highly potent capsid assembly modulator (CAM) candidate evaluated in a Phase 1b study.
- Chronic hepatitis delta virus infection, where ABI‑6250 is being studied as an orally bioavailable HDV entry inhibitor candidate in a Phase 1a trial in healthy participants.
These candidates are explicitly identified in company news releases and SEC filings as investigational products that have not been approved anywhere globally, and their safety and efficacy have not been established.
Pipeline and clinical‑stage programs
Assembly Biosciences describes itself as a clinical‑stage biotechnology company in earlier public descriptions, and its more recent communications detail multiple ongoing clinical studies. The company reports randomized, blinded, placebo‑controlled Phase 1a and Phase 1b trials across its pipeline, with designs focused on safety, tolerability, pharmacokinetics (PK), biomarkers of target engagement and antiviral activity.
For recurrent genital herpes, Assembly Bio is conducting Phase 1b studies of ABI‑5366 and ABI‑1179 in participants seropositive for HSV‑2 with recurrent genital herpes. Company press releases describe ABI‑5366 and ABI‑1179 as long‑acting HSV helicase‑primase inhibitor candidates administered orally on weekly or monthly regimens. Interim analyses reported by the company highlight reductions in HSV‑2 shedding rates, high viral load shedding and genital lesion rates compared to placebo in certain dosing cohorts, along with pharmacokinetic profiles that support once‑weekly and potentially once‑monthly dosing for ABI‑5366 and once‑weekly dosing for ABI‑1179.
For chronic HBV infection, Assembly Bio has reported Phase 1b data for ABI‑4334 in individuals with HBeAg‑negative chronic hepatitis B infection not suppressed on nucleoside analogues. The company describes ABI‑4334 as a next‑generation capsid assembly modulator with high potency, and it has reported multi‑log declines in HBV DNA and pregenomic RNA (pgRNA) consistent with suppression of viral replication in the studied population.
For HDV, the company is evaluating ABI‑6250 in a Phase 1a clinical study in healthy participants. Public interim data indicate that ABI‑6250 is an orally bioavailable small‑molecule entry inhibitor candidate targeting the sodium taurocholate cotransporting polypeptide (NTCP), which Assembly Bio identifies as the receptor used by HDV to infect hepatocytes. The company reports a mean half‑life of approximately four days in the evaluated cohorts, supporting a once‑daily oral dosing profile, as well as dose‑dependent elevations in total serum bile acids as a biomarker of NTCP engagement.
Collaboration with Gilead Sciences
Assembly Biosciences has an ongoing collaboration with Gilead Sciences, Inc., described in multiple press releases and an 8‑K filing. Under this collaboration, Gilead has rights to opt in to exclusive licenses for certain Assembly Bio programs after reviewing option data packages. Company communications state that ABI‑1179 was contributed by Gilead under the collaboration, and that Gilead has option rights for the HSV helicase‑primase inhibitor program and the ABI‑4334 capsid assembly modulator program.
In a joint press release, Assembly Bio and Gilead announced that Gilead exercised its combined option to exclusively license Assembly Bio’s HSV helicase‑primase inhibitor programs for recurrent genital herpes, including ABI‑1179 and ABI‑5366. According to that announcement, Gilead will receive an exclusive license and will assume sole responsibility for further clinical development and commercialization of these HSV programs, while Assembly Bio remains eligible for regulatory and commercial milestone payments, tiered royalties on net sales, and has an option to share in costs and profits in the United States under certain conditions.
Financial position and capital markets activity
Assembly Biosciences provides regular financial updates through quarterly press releases and corresponding Form 8‑K filings. These communications describe collaboration revenue from Gilead, research and development expenses associated with its HSV, HBV and HDV programs, and general and administrative expenses. The company reports that its common stock is registered under Section 12(b) of the Exchange Act and trades on The Nasdaq Global Select Market under the symbol ASMB.
In an 8‑K filing and accompanying press release, Assembly Bio disclosed that it entered into an underwriting agreement for an underwritten, registered offering of common stock, pre‑funded warrants and accompanying Class A and Class B warrants, as well as a separate securities purchase agreement with Gilead for a private placement of common stock and warrants. The company stated that it intends to use the net proceeds from these financings for general corporate purposes and that the transactions are expected to support ongoing and future clinical development.
Regulatory disclosures and risk considerations
Assembly Biosciences files current reports on Form 8‑K with the U.S. Securities and Exchange Commission (SEC) to disclose material events, including clinical data announcements, financing transactions and financial results. The company’s press releases and SEC filings include forward‑looking statements that are subject to risks and uncertainties, such as the ability to initiate and complete clinical studies as planned, to realize the potential benefits of the collaboration with Gilead, to secure additional funding, and to differentiate its product candidates from those of other companies.
In its public statements, Assembly Bio emphasizes that ABI‑5366, ABI‑1179, ABI‑4334 and ABI‑6250 are investigational product candidates. The company notes that these candidates have not been approved anywhere globally and that their safety and efficacy have not been established. It also highlights that results from nonclinical studies may not predict clinical outcomes and that interim clinical data may evolve as studies are completed and additional analyses are performed.
Business context for investors
From an investor perspective, Assembly Biosciences represents a clinical‑stage biotechnology company in the pharmaceutical preparation manufacturing industry, with a focused pipeline targeting serious viral diseases. Its business model, as described in public communications, combines internal discovery and development of small‑molecule antivirals with a strategic collaboration with Gilead Sciences. Revenue reported in recent periods is primarily from collaborative research with Gilead, reflecting funding and cost sharing under the collaboration agreement.
Investors reviewing ASMB may consider the company’s progress in advancing its HSV, HBV and HDV programs through early‑stage clinical development, the structure and potential economics of its collaboration with Gilead, and its use of capital from equity offerings and private placements. Assembly Bio’s SEC filings, including 8‑K reports and financial statements, provide additional detail on its cash position, deferred revenue from collaboration, operating expenses and accumulated deficit.
Frequently asked questions about Assembly Biosciences (ASMB)
The following questions and answers summarize key points drawn directly from Assembly Biosciences’ public disclosures and regulatory filings.
Stock Performance
Assembly Bioscie (ASMB) stock last traded at $28.46, up 0.42% from the previous close. Over the past 12 months, the stock has gained 157.0%. At a market capitalization of $435.1M, ASMB is classified as a small-cap stock with approximately 15.9M shares outstanding.
Latest News
Assembly Bioscie has 10 recent news articles, with the latest published 4 days ago. Of the recent coverage, 8 articles coincided with positive price movement and 2 with negative movement. Key topics include earnings, clinical trial, conferences. View all ASMB news →
SEC Filings
Assembly Bioscie has filed 5 recent SEC filings, including 1 Form S-3, 1 Form 10-K, 1 Form 8-K, 1 Form SCHEDULE 13G/A. The most recent filing was submitted on March 19, 2026. SEC filings provide transparency into a company's financial condition, material events, and regulatory compliance. View all ASMB SEC filings →
Financial Highlights
Assembly Bioscie generated $72.3M in revenue over the trailing twelve months, operating income reached -$12.1M (-16.8% operating margin), and net income was -$6.1M, reflecting a -8.5% net profit margin. Diluted earnings per share stood at $-0.55. The company generated -$41.1M in operating cash flow. With a current ratio of 5.22, the balance sheet reflects a strong liquidity position.
Upcoming Events
Phase 2 trial start
Phase 2 initiation
Phase 2 trial initiation
ABI-6250 Phase 2 initiation
Assembly Bioscie has 4 upcoming scheduled events. The next event, "Phase 2 trial start", is scheduled for May 1, 2026 (in 38 days). Investors can track these dates to stay informed about potential catalysts that may affect the ASMB stock price.
Short Interest History
Short interest in Assembly Bioscie (ASMB) currently stands at 1.5 million shares, down 1.7% from the previous reporting period, representing 14.5% of the float. Over the past 12 months, short interest has increased by 8872.9%. This moderate level of short interest indicates notable bearish positioning. With 14.0 days to cover, it would take significant time for short sellers to close their positions based on average trading volume.
Days to Cover History
Days to cover for Assembly Bioscie (ASMB) currently stands at 14.0 days, down 8.4% from the previous period. This elevated days-to-cover ratio indicates it would take over two weeks of average trading volume for short sellers to exit their positions, suggesting potential for a short squeeze if positive news emerges. The days to cover has increased 1299% over the past year, indicating improving liquidity conditions. The ratio has shown significant volatility over the period, ranging from 1.0 to 15.3 days.
ASMB Company Profile & Sector Positioning
Assembly Bioscie (ASMB) operates in the Biotechnology industry within the broader Pharmaceutical Preparations sector and is listed on the NASDAQ.
Investors comparing ASMB often look at related companies in the same sector, including Larimar Therapeutics Inc (LRMR), Tectonic Therapeutic Inc (TECX), Y-Mabs Therapeutics (YMAB), Benitec Biopharm (BNTC), and Rocket Pharmaceu (RCKT). Comparing financial metrics, valuation ratios, and stock performance across these peers can help investors evaluate ASMB's relative position within its industry.