ARN-75039 Lassa Fever Treatment in West Africa

NCT07419373 | Active Not Recruiting Phase 2 DMC FDA Drug

• 2 other identifiers: ARN-75039-201MCDC2001-010
• Study Type: interventional
• Target: 135
• Locations: 2 countries
• Sites: 4

Brief Summary

This multicenter, randomized, open-label Phase 2 clinical trial evaluates the safety, tolerability, and virologic efficacy of ARN-75039, a novel oral antiviral, for treating Lassa fever in hospitalized adults in West Africa. The study is conducted within the INTEGRATE platform and compares two oral dose regimens of ARN-75039 (100 mg BID and 50 mg BID) with intravenous ribavirin, the locally mandated standard of care. Approximately 135 participants with RT-PCR-confirmed Lassa virus infection will be enrolled and randomized 1:1:1 to receive ARN-75039 high dose, ARN-75039 low dose, or ribavirin for 10 days, followed by safety and efficacy follow-up through Day 28. The primary objectives are to assess safety and tolerability and to evaluate antiviral activity, as measured by the change in slope of Lassa virus RT-PCR cycle threshold (Ct) values from Day 1 to Day 10, in participants with low baseline viral load Ct values. Secondary objectives include additional virologic, pharmacokinetic, and clinical outcome assessments, including time to viral clearance, symptom resolution, organ failure, and mortality. ARN-75039 is a small-molecule viral entry inhibitor targeting the Lassa virus glycoprotein complex and has demonstrated potent antiviral activity and favorable safety and pharmacokinetic profiles in preclinical models and Phase 1 clinical studies. This study aims to inform dose selection and support further clinical development of ARN-75039 as a potential treatment for Lassa fever.

Conditions

Lassa Fever

Keywords

Emerging infectious diseases; Neglected tropical diseases; Viral hemorrhagic fever; Viral entry inhibitor; Ribavirin comparator; INTEGRATE platform trial; Lassa virus; Lassa virus infection; RT-PCR viral load; ARN-75039; Glycoprotein fusion inhibitor

Outcome Measures

Primary Outcomes (2)

• Incidence of Treatment-Emergent Adverse Events (TEAEs) Grade ≥3

  Type and frequency of treatment-emergent adverse events of Grade 3 or higher

  Day 1 through Day 28

• Change in Viral Load Slope (RT-PCR Ct Values)

  Change in slope of Lassa virus RT-PCR cycle threshold (Ct) values between Day 1 and Day 10 in participants with low baseline Ct values.

  Day 1 to Day 10

Secondary Outcomes (34)

• Change in Viral Load Slope in Participants with Other Baseline Ct Values

  Day 1 to Day 10

• Change in RT-PCR Ct Values at Prespecified Timepoints (Change in Ct values. between Day 1 and Days 2, 3, 4, 6, 8, and 10).

  Day 1 to Day 10

• Time to First RT-PCR Result Below Lower Limit of Quantification (LLOQ)

  Day 1 to Day 28

• Time to First Undetectable Lassa Virus RT-PCR Result

  Day 1 to Day 28

• Proportion of Participants With RT-PCR <LLOQ

  Day 1 to Day 28

Study Arms (3)

ARN-75039: 100 mg maintenance (high oral dose)

EXPERIMENTAL

ARN-75039 is an investigational oral antiviral agent administered as tablets. This high dose regimen includes a 300 mg initial dose and 200 second dose on day 1, followed by a 200 mg BID dose on day 2 and 100 mg BID days 3-10.

Drug: ARN-75039 high

ARN-75039: 50 mg maintenance (low oral dose)

EXPERIMENTAL

ARN-75039 is an investigational oral antiviral agent administered as tablets. This high dose regimen includes a 150 mg initial dose and 100 second dose on day 1, followed by a 100 mg BID dose on day 2 and 50 mg BID days 3-10.

Drug: ARN-75039 low

Ribavirin intravenous (IV)

ACTIVE COMPARATOR

Standard of Care "Irrua regimen"

Drug: Intravenous ribavirin

Interventions

ARN-75039 high DRUG

ARN-75039 (100 mg maintenance) high dose

ARN-75039: 100 mg maintenance (high oral dose)

Intravenous ribavirin DRUG

Irrua Regimen SOC

Ribavirin intravenous (IV)

ARN-75039 low DRUG

ARN-75039 (50 mg maintenance) low dose

ARN-75039: 50 mg maintenance (low oral dose)

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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

Sponsors & Collaborators

• Arisan Therapeutics, Inc.: lead
• Irrua Specialist Teaching Hospital: collaborator
• Bernhard Nocht Institute for Tropical Medicine: collaborator
• Federal Medical Centre, Owo: collaborator
• ANRS, Emerging Infectious Diseases: collaborator
• Battelle Memorial Institute: collaborator
• JPEO, Chemical, Biological, Radiological, and Nuclear, Medical: collaborator
• Alliance for International Medical Action: collaborator

Study Sites (4)

Arisan Therapeutics

Carlsbad, California, 92008, United States

Location

Federal Medical Centre, Owo

Owo, Ondo State, Nigeria

Location

Abubakar Tafawa Balewa University Teaching Hospital

Bauchi, Nigeria

Location

Irrua Specialist Teaching Hospital

Irrua, 310115, Nigeria

Location

MeSH Terms

Conditions

Lassa Fever; Communicable Diseases, Emerging; Neglected Diseases; Hemorrhagic Fevers, Viral

Condition Hierarchy (Ancestors)

Arenaviridae Infections; RNA Virus Infections; Virus Diseases; Infections; Communicable Diseases; Disease Attributes; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Officials

• Ken McCormack, PhD

  Arisan Therapeutics, Inc.

  STUDY CHAIR

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: This study is conducted without masking. Participants, care providers, investigators, and some outcomes assessors are aware of the treatment assignments. Viremia and PK assessors will be masked.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Drug: ARN-75039 100 mg oral dose (high dose) Drug: ARN-75039 50 mg oral dose (low dose) Comparator: Ribavirin intravenous (IV), "Irrua regimen" (SOC)

Study Record Dates

• First Submitted: February 2, 2026
• First Posted: February 19, 2026
• Study Start: February 14, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): June 1, 2027
• Last Updated: June 1, 2026

Record last verified: 2026-02

Locations

US (1); NG (3)