Assembly Biosciences Presents New Data Highlighting Long-Acting Herpes Simplex Virus Candidate ABI-5366 and Genital Herpes Prevalence and Treatment Patterns at the 2025 ESCMID Congress
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 (NASDAQ: ASMB) ha presentato nuovi dati per il suo programma sul virus dell'herpes simplex (HSV) al Congresso ESCMID 2025, presentando risultati clinici e preclinici per ABI-5366, un nuovo candidato inibitore della elicasi-primasi a lunga durata d'azione.
I risultati chiave dello studio di Fase 1a hanno mostrato che ABI-5366 è stato ben tollerato fino a 350 mg senza eventi avversi gravi. Il farmaco ha dimostrato una emivita di circa 20 giorni, supportando la potenziale somministrazione orale settimanale o mensile. Gli studi preclinici hanno rivelato un'ampia attività contro sia HSV-1 che HSV-2.
Un'analisi retrospettiva dei dati sanitari statunitensi ha identificato 262.457 casi totali di herpes genitale e 148.067 casi ricorrenti nel 2023. Quando extrapolato alla popolazione statunitense, circa 1,35 milioni di individui sperimentano herpes genitale ricorrente, con oltre 800.000 che ricevono terapia soppressiva cronica o intermittente.
L'azienda prevede di riportare dati provvisori della Fase 1b sia per ABI-5366 che per ABI-1179 nell'autunno del 2025.
Assembly Biosciences (NASDAQ: ASMB) presentó nuevos datos para su programa sobre el virus del herpes simple (HSV) en el Congreso ESCMID 2025, mostrando resultados clínicos y preclínicos para ABI-5366, un nuevo candidato inhibidor de helicasa-primasa de larga duración.
Los hallazgos clave del estudio de Fase 1a mostraron que ABI-5366 fue bien tolerado hasta 350 mg sin eventos adversos graves. El fármaco demostró una vida media de aproximadamente 20 días, lo que apoya la posible administración oral una vez a la semana o mensualmente. Los estudios preclínicos revelaron una amplia actividad contra HSV-1 y HSV-2.
Un análisis retrospectivo de los datos de salud de EE. UU. identificó 262,457 casos totales de herpes genital y 148,067 casos recurrentes en 2023. Cuando se extrapola a la población de EE. UU., aproximadamente 1.35 millones de individuos experimentan herpes genital recurrente, con más de 800,000 recibiendo terapia supresiva crónica o intermitente.
La empresa espera informar sobre datos interinos de la Fase 1b tanto para ABI-5366 como para ABI-1179 en otoño de 2025.
어셈블리 바이오사이언스 (NASDAQ: ASMB)는 2025 ESCMID Congress에서 단순 포진 바이러스 (HSV) 프로그램에 대한 새로운 데이터를 발표하였으며, ABI-5366라는 새로운 장기 작용 헬리케이스-프리마제 억제제 후보의 임상 및 전임상 결과를 포함하고 있습니다.
1a상 연구의 주요 결과는 ABI-5366이 350mg까지 잘 견디며 심각한 부작용이 없음을 보여주었습니다. 이 약물은 약 20일의 반감기를 나타내어 주 1회 또는 월 1회의 경구 투여 가능성을 뒷받침합니다. 전임상 연구에서는 HSV-1과 HSV-2 모두에 대한 광범위한 활성을 밝혔습니다.
미국 의료 데이터에 대한 후향적 분석에서 총 262,457건의 생식기 포진 사례와 2023년 148,067건의 재발 사례가 확인되었습니다. 미국 인구에 추정할 때 약 135만 명이 재발성 생식기 포진을 경험하며, 80만 명 이상이 만성 또는 간헐적 억제 치료를 받고 있습니다.
회사는 2025년 가을에 ABI-5366 및 ABI-1179에 대한 중간 1b상 데이터를 보고할 것으로 예상하고 있습니다.
Assembly Biosciences (NASDAQ: ASMB) a présenté de nouvelles données pour son programme sur le virus de l'herpès simplex (HSV) lors du Congrès ESCMID 2025, présentant des résultats cliniques et précliniques pour ABI-5366, un nouveau candidat inhibiteur de l'hélicase-primase à action prolongée.
Les principales conclusions de l'étude de Phase 1a ont montré qu'ABI-5366 était bien toléré jusqu'à 350 mg sans événements indésirables graves. Le médicament a démontré une demi-vie d'environ 20 jours, soutenant une administration orale potentielle une fois par semaine ou par mois. Des études précliniques ont révélé une large activité contre HSV-1 et HSV-2.
Une analyse rétrospective des données de santé américaines a identifié 262 457 cas totaux d'herpès génital et 148 067 cas récurrents en 2023. Lorsqu'on extrapole à la population américaine, environ 1,35 million d'individus souffrent d'herpès génital récurrent, dont plus de 800 000 reçoivent une thérapie suppressive chronique ou intermittente.
L'entreprise s'attend à rapporter des données intermédiaires de la Phase 1b pour ABI-5366 et ABI-1179 à l'automne 2025.
Assembly Biosciences (NASDAQ: ASMB) präsentierte neue Daten für sein Herpes-simplex-Virus (HSV)-Programm auf dem ESCMID-Kongress 2025, die klinische und präklinische Ergebnisse für ABI-5366, einen neuartigen langwirksamen Helikase-Primase-Inhibitor, umfassen.
Wichtige Ergebnisse aus der Phase-1a-Studie zeigten, dass ABI-5366 bis zu 350 mg gut vertragen wurde, ohne schwerwiegende unerwünschte Ereignisse. Das Medikament zeigte eine ungefähre Halbwertszeit von 20 Tagen, was die potenzielle einmal wöchentliche oder monatliche orale Verabreichung unterstützt. Präklinische Studien zeigten eine breite Aktivität gegen sowohl HSV-1 als auch HSV-2.
Eine retrospektive Analyse von US-Gesundheitsdaten identifizierte 262.457 insgesamt Fälle von Genitalherpes und 148.067 wiederkehrende Fälle im Jahr 2023. Hochgerechnet auf die US-Bevölkerung erleben etwa 1,35 Millionen Menschen wiederkehrenden Genitalherpes, wobei über 800.000 eine chronische oder intermittierende suppressive Therapie erhalten.
Das Unternehmen erwartet, im Herbst 2025 interimistische Daten der Phase 1b sowohl für ABI-5366 als auch für ABI-1179 zu berichten.
- Phase 1a trial demonstrated positive safety profile with no serious adverse events
- Drug's 20-day half-life enables convenient once-weekly or monthly dosing
- Broad effectiveness against both HSV-1 and HSV-2 variants in preclinical studies
- Large addressable market with 1.35 million recurring genital herpes patients in the US
- Product still in early clinical development phase
- Final proof-of-concept data not yet available
- Faces competition from existing treatments in the market
Insights
Assembly Biosciences' presentation of new data for its HSV candidates represents meaningful progress for its clinical pipeline. The Phase 1a safety data for ABI-5366 demonstrates favorable tolerability with no serious adverse events reported, while the approximately 20-day half-life supports the company's differentiated positioning for a potentially once-weekly or once-monthly oral treatment regimen - a significant improvement over current daily antiviral therapies that have remained largely unchanged for decades.
The market research data presented is particularly compelling, suggesting an estimated 1.35 million individuals with recurrent genital herpes in the US, with over 800,000 patients receiving chronic or intermittent suppressive therapy. The identification that 28% of genital herpes patients receive no interventions highlights both undertreatment and potential commercial opportunity.
While this remains an early-stage program with pivotal efficacy data still pending, the concurrent advancement of two long-acting helicase-primase inhibitors (ABI-5366 and ABI-1179) demonstrates rational pipeline development. The expected interim Phase 1b readout in fall 2025 represents a meaningful near-term catalyst that could validate the program's potential. For Assembly Bio, which has a modest market capitalization of approximately
The clinical and preclinical data for ABI-5366 addresses a significant unmet need in HSV treatment. Current standard-of-care antivirals like acyclovir and valacyclovir require daily dosing for suppressive therapy, creating adherence challenges that impact long-term disease management. The 20-day half-life demonstrated by ABI-5366 represents a potential breakthrough in treatment paradigms for recurrent genital herpes.
The mechanism of targeting the viral helicase-primase complex is particularly promising, as it offers a novel approach compared to traditional nucleoside analogs. The reported broad activity against both HSV-1 and HSV-2 clinical isolates expands the potential therapeutic applications. Additionally, the demonstrated distribution to tissues relevant to HSV infection suggests appropriate pharmacokinetic properties for clinical efficacy.
The epidemiological data presented provides valuable insights into treatment patterns, revealing that only 57% of recurrent genital herpes patients receive suppressive therapy despite its established benefits for reducing transmission and outbreaks. This highlights substantial gaps in optimal disease management that a more convenient dosing regimen could help address. If ABI-5366 can demonstrate efficacy comparable to daily antivirals with significantly reduced dosing frequency, it could substantially improve disease management and quality of life for affected patients while potentially reducing transmission rates to uninfected partners.
– Clinical and preclinical data supporting dosing profile and tolerability for ABI-5366, a novel long-acting helicase-primase inhibitor candidate, featured in two poster presentations –
– Additional poster presentation highlights new insights in genital herpes prevalence and treatment patterns in the U.S. –
– ABI-5366 is currently being evaluated in ongoing Phase 1b clinical trial with interim proof-of-concept data expected in fall 2025 –
SOUTH SAN FRANCISCO, Calif., April 09, 2025 (GLOBE NEWSWIRE) -- Assembly Biosciences, Inc. (Nasdaq: ASMB), a biotechnology company developing innovative therapeutics targeting serious viral diseases, today announced data from its herpes simplex virus (HSV) program featured in three poster presentations at the 2025 Congress of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) taking place in Vienna, Austria, on April 11-15, 2025.
“We are encouraged by the data shared from our clinical and preclinical studies of ABI-5366, supporting its potential to be a once-weekly or once-monthly oral treatment option for those with recurrent genital herpes, an underserved disease space,” said Anuj Gaggar, MD, PhD, chief medical officer of Assembly Bio. “Importantly, our analysis of genital herpes prevalence and treatment patterns further underscores the substantial burden of genital herpes in the United States and wide variability in antiviral treatment patterns. This guides our efforts to improve therapeutic options in a field that has seen little innovation for decades.”
ABI-5366: a Long-Acting Helicase-Primase Inhibitor Candidate for Recurrent Genital Herpes
The ePoster entitled “The safety and pharmacokinetics of ABI-5366, a novel, oral, long-acting HSV helicase-primase inhibitor: Interim results from a Phase 1a/1b study in healthy participants” showcases clinical data from a single-dose Phase 1a evaluation of safety and pharmacokinetics (PK) of ABI-5366 in healthy participants. Results demonstrate that ABI-5366 was well tolerated when administered orally up to 350 mg with no Grade 3 or 4 treatment-related laboratory abnormalities or serious adverse events (AEs) reported. Further, an observed half-life of approximately 20 days across all dosing cohorts supports the potential for once-weekly or once-monthly oral administration.
Additionally, the poster entitled “Preclinical profile of ABI-5366, a novel potent HSV helicase-primase inhibitor, with potential for weekly or monthly oral dosing for the treatment of recurrent genital herpes” highlights results from preclinical studies of ABI-5366, in which broad activity against both HSV type 1 (HSV-1) and HSV type 2 (HSV-2) clinical isolates was observed. Preclinical data also reinforce a PK profile supportive of the potential for once-weekly or once-monthly oral dosing and demonstrate distribution of ABI-5366 to tissues relevant to HSV infection.
ABI-5366 is being evaluated in the Phase 1b portion of an ongoing Phase 1a/b study in participants with recurrent genital herpes. Assembly Bio expects to report interim Phase 1b data for both ABI-5366 and ABI-1179, a second long-acting helicase-primase inhibitor candidate, in fall 2025.
Genital Herpes Prevalence and Treatment Patterns
The poster entitled “Estimating Genital Herpes Prevalence and Treatment Patterns Among U.S. Healthcare-Engaged Individuals: Insights from Claims Data” features results from a retrospective analysis of data from Forian’s hybrid claims ecosystem and electronic health record (EHR) database, CHRONOS, of more than 40 million individuals to estimate genital herpes prevalence and treatment patterns. The analysis identified an estimated 262,457 total genital herpes cases and 148,067 recurrent cases in 2023 among the study sample, with the highest prevalence observed among females and those aged 18-39. These estimates reflect ICD-10-CM codes and symptom capture in a defined time period using a study sample of individuals engaged in the healthcare system. Extrapolated to the U.S. population, approximately 1.35 million individuals were estimated to experience recurrent genital herpes, with over 800,000 individuals estimated to receive chronic or intermittent suppressive therapy.
Among all genital herpes patients, an estimated
Assembly Bio intends to make the posters available on the “Events & Presentations” page in the “Investors” section of its website at www.assemblybio.com.
ABI-1179 and ABI-5366 are investigational product candidates that have not been approved anywhere globally, and their safety and efficacy have not been established. ABI-1179 was contributed by Gilead Sciences, Inc. (Gilead) under the collaboration between Assembly Bio and Gilead.
About Recurrent Genital Herpes
Genital herpes is a chronic viral infection caused by the herpes simplex virus (HSV) that can result in painful genital lesions, serious psychological and social impacts, and an increased risk of acquiring human immunodeficiency virus (HIV). Most people with initial symptomatic genital HSV type 2 (HSV-2) infection have three or more recurrences per year, with epidemiologic studies estimating over four million people in the United States and France, Germany, Italy, Spain and the United Kingdom experience recurrent genital herpes. While genital herpes can be caused by either HSV type 1 (HSV-1) or HSV-2, recurrences are more likely to be experienced by individuals infected by HSV-2. The current standard of care for recurrent genital herpes is nucleoside analogs given intermittently for recurrences or as daily chronic suppressive therapy; however, these are only partially effective in preventing recurrences and in reducing transmission of the virus. No new drugs have been approved in the United States or Europe to treat genital herpes for more than 25 years.
About Helicase-Primase Inhibition
HSV helicase-primase inhibitors target the viral helicase-primase complex, an essential viral enzyme complex that is conserved across both HSV-1 and HSV-2 and has no host equivalent. Inhibition of the helicase-primase complex is a clinically validated mechanism that has shown the potential for superior efficacy to the current standard of care, nucleoside analogs, in short-duration clinical studies in participants with recurrent genital herpes.
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 maintain financial resources necessary to continue its research activities, clinical studies and other business operations; 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
FAQ
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