Study to Determine the Efficacy&Safety of ARV-1801(ACG-701) for the Treatment of Cystic Fibrosis Pulmonary Exacerbations

This is a Phase 2, randomized, double-blind, multicenter study designed to evaluate the efficacy and safety of an oral ARV-1801/ACG-701 plus OBT compared to oral placebo plus OBT, each administered for 14 days, in the treatment of participants with CF-related PEx. Participants who provide informed consent (plus informed assent, if applicable) and meet all study eligibility criteria will be enrolled in the study and randomized via an interactive response technology (IRT) in a 1:1 ratio to receive ARV-1801/ACG-701 or placebo in addition to OBT for 14 days. A participant may be hospitalized (inpatient) or treated as an outpatient. If admitted to the hospital for initial treatment, the participant may be discharged at the Investigator's discretion to complete study therapy as an outpatient. The target study population will comprise 80 participants. The duration of participation in the study for an individual participant will be approximately 28 days and will involve up to 5 clinic visits as well as the requirement to complete an electronic symptom questionnaire every day for the duration of the study. Participation will include a Screening period of up to 24 hours prior to the first dose of study drug (Day 1), a 14 day treatment course of study drug, a Day 7 visit (±1 day), an end of treatment (EOT) visit (day of last dose of study drug +3 days), and end of study (EOS) visit on Day 28 (+3 days).