ARN-75039 Lassa Fever Treatment in West Africa

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.