ARN-75039

Lassa fever (LF) is a viral haemorrhagic fever responsible of 5000 deaths per year in West Africa, with in-hospital mortality at 12%. Transmission to humans occurs mainly via direct or indirect exposure to excreta from the rodent reservoir, mainly made up of Mastomys natalensis . Less frequently, LASV may also be transmitted from human to human and cause nosocomial outbreaks. Ribavirin is the only treatment available with worrying toxicity, questionable efficacy and low access because of its high cost. Consequently, there is an urgent need for new drugs to treat LF patients. The Research and Development (R&D) Blueprint of the World Health Organization (WHO) has included LF in the list of priority diseases for urgent research and development.
The INTEGRATE consortium is an unprecedented international collaboration on Lassa fever of 15 partners from 10 countries across West Africa, Europe and North America and across several disciplines (epidemiological researchers, social scientists, medical health facility professionals, humanitarian actors, etc.).

ARN-75039-103 is a comparative, randomized, single-dose, cross-over study to assess the PK, safety, and tolerability of neat ARN-75039 in hydroxypropyl methylcellulose (HPMC) capsules compared with ARN-75039 with excipients in tablet form, both administered orally, in healthy adult participants. The safety assessments will include standard evaluations of vital signs, clinical laboratory values, and ECGs.
Participants will be admitted to the study site on the morning of Day -1, before Period 1 study drug administration, and will remain on site until Day 15. Upon confirmation of eligibility, participants will be randomized into the study on Day 1. Study drug administration will be performed on the first day of Periods 1 and 2 (Study Days 1 and 8, respectively) with a 7-day washout period between the two periods. Participants will receive the randomized study drug in the morning following a meal. A total of 16 participants will be randomized 1:1 to the following two sequences:
* Sequence 1:
* Form A: Neat ARN-75039 in HPMC capsules (reference product)
* Form B: ARN-75039 with excipients in tablet form (comparator)
* Sequence 2:
* Form B: ARN-75039 with excipients in tablet form (comparator)
* Form A: Neat ARN-75039 in HPMC capsules (reference product)
Participation in the study will be conducted in the following 5 defined periods:
* Screening Period: The Screening Period begins upon completion of the informed consent form (ICF). During this period, participants will undergo baseline assessments to determine eligibility for study participation. The Screening Period duration will be up to 21 days; it will end after all evaluations required to meet eligibility have been completed. If a participant meets all eligibility criteria, they will be offered enrollment into the study.
* Admission to Study Site: Participants will be admitted to the study site in the morning on the day before dosing of period 1 (Day -1). Participants who are eligible to participate in the study and are randomized into the study will remain at the study site until completion of the treatment period (Study Day 15).
* Treatment Period: This study consists of two treatment days separated by a 7-day washout period. The first treatment day will begin on Day 1 of Period 1 with administration of the first dose of study drug. The second treatment day will occur on the first day of Period 2 (Study Day 8). Following the dosing of the study drug on each treatment day, fifteen venous blood samples will be withdrawn via an indwelling cannula or by venipuncture at regular time intervals.
* End of Active Treatment (Day 15 Discharge Visit or Early Termination (ET) Visit): Upon successful completion of active treatment, participants will be discharged from the study site on Study Day 15. The Discharge Visit will include the completion of safety assessments, such as a physical examination, vitals, ECG recording, adverse event review, and clinical laboratory tests. Participants who complete both dosing days will be encouraged to complete all study visits.
Participants who do not complete all study visits or terminate from the study before Day 15 will be asked to complete The Early Termination Visit is within 1 day after withdrawal from the study.
• Day 36 Telephone Follow-Up Phone Call: Participants will be contacted by phone on Day 36-i.e., 28 days following the last study dose administered on Day 8. The purpose of this follow-up call is to assess for any adverse events.