ARN-75039 oral treatment for Lassa fever in West Africa

A Phase 2 Study to Evaluate Safety, Tolerability, And Virologic Efficacy of ARN-75039 For the Treatment of Lassa Fever in West Africa

Phase 2 Interventional Arisan Therapeutics, Inc. · NCT07419373

This study will test whether two doses of the oral antiviral ARN-75039 work as well as or better than standard intravenous ribavirin in adults hospitalized with confirmed Lassa fever in West Africa.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment135 (estimated)
Ages18 Years and up
SexAll
SponsorArisan Therapeutics, Inc. Industry-sponsored
Locations4 sites (Carlsbad, California and 3 other locations)
Trial IDNCT07419373 on ClinicalTrials.gov

What this trial studies

This is a randomized, open-label Phase 2 trial within the INTEGRATE platform comparing two oral dose regimens of ARN-75039 (100 mg BID and 50 mg BID) to locally mandated intravenous ribavirin. About 135 adults with RT-PCR-confirmed Lassa virus infection will be randomized 1:1:1 and treated as inpatients for 10 days, with follow-up through Day 28. The primary endpoints focus on safety, tolerability, and antiviral activity measured by change in RT-PCR cycle threshold (Ct) slope from Day 1 to Day 10, with randomization stratified by viral lineage and baseline viral load. Sites are specialized treatment centers in West Africa with diagnostic and inpatient Lassa care capacity and operate under coordinated regional and U.S. oversight.

Who should consider this trial

Good fit: Adults aged 18 or older who are hospitalized with clinical disease and RT-PCR-confirmed Lassa virus infection and who can provide informed consent are the ideal candidates.

Not a fit: People who are pregnant, recently received ribavirin or other specific Lassa therapies, have severe chronic liver or cardiac disease, or cannot be hospitalized at a participating site are unlikely to be eligible or benefit from enrollment.

Why it matters

Potential benefit: If effective, an oral antiviral could shorten illness, reduce complications and deaths, and make Lassa treatment easier to deliver than intravenous ribavirin.

How similar studies have performed: Ribavirin has been used historically with mixed evidence, while ARN-75039 is a novel oral viral-entry inhibitor with supportive preclinical and Phase 1 safety data but has not yet proven clinical effectiveness in large Lassa trials.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

Participants must meet all of the following criteria to be eligible for enrollment:

* Age ≥ 18 years
* Hospitalized with clinical disease consistent with Lassa fever
* Positive plasma Lassa virus RT-PCR at screening
* Requires hospitalization for Lassa fever per local clinical guidelines
* Able to provide written informed consent, or consent provided by a legally authorized representative.

Exclusion Criteria:

Participants will be excluded if they meet any of the following criteria:

* Pregnant (confirmed by positive urine pregnancy test in women of childbearing potential)
* Receipt of specific drug therapy for Lassa fever (e.g., ribavirin, direct antivirals, or host-directed therapies including corticosteroids) within 15 days before enrollment
* Prior vaccination against Lassa fever
* History of severe gastrointestinal disease
* History of chronic generalized pruritus
* History of severe chronic liver disease
* History of severe cardiac disorder

Sex and Reproductive Criteria

* Women of childbearing potential must have a negative pregnancy test at screening
* Breastfeeding is not permitted during the treatment period and early follow-up
* Participants must agree to comply with protocol-defined contraception requirements

Where this trial is running

Carlsbad, California and 3 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Lassa FeverEmerging infectious diseasesNeglected tropical diseasesViral hemorrhagic feverViral entry inhibitorRibavirin comparatorINTEGRATE platform trialLassa virus
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.