Some subjects could not complete the second crossover period due to COVID-19-related site closure. The study was closed to allow analysis of all collected data.

This is a randomized, double-blind, placebo-controlled, 2-way cross-over study in healthy male and female elderly participants.

Participants will receive up to a total of 30 daily doses of study drug (15 days of daily IW-6463, only; 15 days of daily placebo, only) administered across two 15-day dosing periods (Period 1 and Period 2). The dosing periods will be separated by a 27-day washout. Participants will be randomized to a sequence of receiving IW-6463 for Period 1 and then placebo for Period 2, or vice versa.

Inclusion Criteria:

• Subject is an ambulatory adult at least 65 years old at the screening visit
• Subject is in good health and has no clinically significant findings on physical examination
• Female participants must be postmenopausal. A postmenopausal state is defined as no menses for ≥12 consecutive months without an alternative medical cause. A high follicle-stimulating hormone (FSH) level at screening (>40 IU/L or mIU/mL) in the postmenopausal range may be used to confirm a postmenopausal state.
• Male participants who have not been surgically sterilized by vasectomy (conducted ≥60 days before the Screening Visit or confirmed via sperm analysis) must agree contraceptive use per protocol
• Men must also agree to not donate sperm throughout the study and for 3 months after the final dose of study drug
• Other inclusion criteria per protocol

Exclusion Criteria:

• Any active or unstable clinically significant medical condition
• Other exclusion criteria per protocol