Part 1: This is a Phase 1/2 proof-of-concept, double-blind, multicenter, placebo-controlled study to evaluate the safety, pharmacokinetics and efficacy of 3 oral dosing regimens of ATV-1601. Participants who meet eligibility requirements will be randomized in a double-blind manner to one of 3 doses of ATV-1601 or placebo. Participants will receive double-blind study treatment for a 16-week period.
Part 2: Eligible participants who complete Part 1 may enroll in an open-label extension study to receive up to 2 years of additional treatment. All participants in the open-label extension will receive ATV-1601. Once the recommended Phase 2 dose (RP2D) is determined based on Part 1, all participants in Part 2 will have the option to switch to the RP2D.
