A Comparison of the Pharmacokinetic Properties of ARN-75039 Tablets With Excipients to Neat ARN-75039 in Hydroxypropyl Methylcellulose (HPMC) Capsules in Healthy Adult Participants Under Fed Conditions

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