Assembly Bioscie Stock Price, News & Analysis

The company aims to address significant unmet needs in viral hepatitis treatment, with HDV being the most serious form affecting liver health, and HBV affecting 254 million people globally with 1.1 million deaths in 2022.

Assembly Biosciences (NASDAQ: ASMB) presented new data for its herpes simplex virus (HSV) program at the 2025 ESCMID Congress, featuring clinical and preclinical results for ABI-5366, a novel long-acting helicase-primase inhibitor candidate.

Key findings from the Phase 1a study showed ABI-5366 was well-tolerated up to 350mg with no serious adverse events. The drug demonstrated an approximate 20-day half-life, supporting potential once-weekly or monthly oral administration. Preclinical studies revealed broad activity against both HSV-1 and HSV-2.

A retrospective analysis of U.S. healthcare data identified 262,457 total genital herpes cases and 148,067 recurrent cases in 2023. When extrapolated to the U.S. population, approximately 1.35 million individuals experience recurrent genital herpes, with over 800,000 receiving chronic or intermittent suppressive therapy.

The company expects to report interim Phase 1b data for both ABI-5366 and ABI-1179 in fall 2025.

Assembly Biosciences (ASMB) reported its financial results for 2024, highlighting progress across its antiviral pipeline. The company ended 2024 with $112.1 million in cash, projecting operations funding into mid-2026. Revenues increased to $28.5 million from $7.2 million in 2023, while net loss decreased to $40.2 million ($6.69 per share) from $61.2 million in 2023.

Key clinical developments include positive Phase 1a interim data for ABI-1179 for recurrent genital herpes, supporting once-weekly oral dosing. The company's ABI-4334 for chronic HBV infection showed promising results with a 2.9 log10 IU/mL mean decline in HBV DNA. ASMB initiated Phase 1a study for ABI-6250 for hepatitis delta virus and advanced ABI-7423 into IND/CTA-enabling studies.

The company received a $20.1 million equity investment and $10 million in accelerated funding from Gilead Sciences to advance clinical development programs.

Assembly Biosciences (ASMB) has initiated dosing in a Phase 1a clinical trial for ABI-6250, their oral hepatitis delta virus (HDV) entry inhibitor candidate. The study will evaluate safety, tolerability, and pharmacokinetics across single and multiple ascending dose cohorts in healthy participants, with data expected in Q3 2025.

The trial will monitor serum bile acids as a biomarker of ABI-6250's engagement with its target, the NTCP transporter. Currently, only one therapy is approved for chronic HDV infection in the EU, requiring daily injections, with no approved treatments in the US.

In preclinical studies, ABI-6250 has shown low nanomolar potency across multiple HDV genotypes, selectivity for NTCP versus other bile acid transporters, and a pharmacokinetic profile supporting once-daily oral dosing. Chronic HDV is considered the most severe form of viral hepatitis, with 70% of patients progressing to cirrhosis within 10 years.

Assembly Biosciences (NASDAQ: ASMB) reported positive interim Phase 1a results for ABI-1179, their investigational long-acting herpes simplex virus (HSV) helicase-primase inhibitor for recurrent genital herpes. The drug demonstrated a favorable safety profile and approximately four-day half-life, supporting once-weekly oral dosing potential.

Key findings from the Phase 1a trial include:

• Well-tolerated safety profile across all doses (50mg, 100mg, and 300mg)
• Exceeded target plasma concentrations for antiviral activity even at lowest dose
• All treatment-emergent adverse events were mild and deemed unrelated to treatment

The company will advance directly to Phase 1b testing in participants with recurrent genital herpes, running concurrently with their ongoing Phase 1b study of ABI-5366. Interim data for both candidates is expected in fall 2025.

Assembly Biosciences (ASMB) announced interim results from its Phase 1b trial of ABI-4334, a next-generation capsid assembly modulator for chronic hepatitis B virus. The first cohort, receiving 150 mg daily oral dose, showed strong antiviral activity with a mean HBV DNA reduction of 2.9 log IU/mL over 28 days. The drug demonstrated favorable safety profile and half-life supporting once-daily dosing.

Among participants with detectable HBV RNA at baseline, a mean decline of 2.5 log10 U/mL was observed. Enrollment is ongoing for the final 400 mg cohort, with data expected in 1H 2025. Under the collaboration agreement, Gilead has the option to further develop and commercialize ABI-4334 after Phase 1b study completion.

Assembly Biosciences (ASMB) has secured a significant financial boost through a $30.1 million investment from Gilead Sciences, comprising a $20.1 million equity investment and $10 million in accelerated funding. This investment increases Gilead's ownership stake in ASMB to 29.9% and extends ASMB's cash runway to mid-2026.

The funding will support ASMB's clinical pipeline development of antiviral therapeutics targeting herpesviruses, hepatitis D virus (HDV), and hepatitis B virus (HBV). The company has initiated clinical studies for four small molecule antiviral candidates: ABI-5366, ABI-4334, ABI-1179, and ABI-6250. An interim Phase 1b proof-of-concept data readout for ABI-5366 is expected in the first half of 2025.

Assembly Biosciences (ASMB) reported Q3 2024 financial results and updates. The company announced positive Phase 1a interim data for ABI-5366, their genital herpes treatment candidate, supporting once-weekly and monthly oral dosing. Cash position was $95.0 million as of September 30, 2024, with funding projected into Q1 2026. Q3 revenue was $6.8 million from Gilead collaboration. R&D expenses increased to $13.5 million, while G&A expenses remained stable at $4.3 million. Net loss was $9.6 million ($1.51 per share), improved from $14.4 million loss in Q3 2023.

Assembly Biosciences (Nasdaq: ASMB) reported positive interim results from the Phase 1a portion of its ongoing Phase 1a/b study evaluating ABI-5366, a long-acting herpes simplex virus (HSV) helicase-primase inhibitor candidate for recurrent genital herpes. Key findings include:

1. ABI-5366 was well-tolerated with a favorable safety profile up to 70 days of exposure.
2. Single doses surpassed target plasma concentrations for antiviral efficacy.
3. Half-life of approximately 20 days supports once-weekly or once-monthly oral dosing.
4. Both weekly and monthly dosing cohorts will be included in Phase 1b.
5. Screening for Phase 1b in participants with recurrent genital herpes has begun.
6. Interim Phase 1b results expected in the first half of 2025.