ARCT-032-02 is a Phase 2, open-label, multicenter, multiple-ascending dose study of ARCT-032 in adults with CF who are not eligible for CFTR modulator therapy or are not taking CFTR modulators due to drug intolerance, poor response, or lack of access to modulators.

This is an open-label, multiple-ascending dose study of ARCT-032 in adults with CF who are not on CFTR modulator therapy. After successful screening, eligible participants enrolled in cohorts 1-3 will receive nebulized ARCT-032 daily for 4 weeks and then will be followed for safety for a total of 12 weeks. In cohort 4, eligible participants will receive nebulized ARCT-032 for 12 weeks and will then be followed for safety for an additional 12 weeks.

Key Inclusion Criteria:

1. Confirmed diagnosis of Cystic Fibrosis
2. Not eligible for CFTR modulator therapy or not taking CFTR modulators for at least 60 days prior to dosing (e.g. due to intolerance, poor response, or lack of access to modulators)
3. FEV1 between 40% to 100% (cohorts 1-3) and 45% to 90% (cohort 4, inclusive) of predicted value for age, sex and height

Exclusion Criteria:

1. History of illness or medical condition that might pose an additional risk or may confound study results
2. Recent moderate or severe hemoptysis
3. Recent major surgery
4. Solid organ or hematologic transplant
5. Requirement of supplemental oxygen while awake or > 2L per minute while sleeping.
6. Chronic maintenance systemic corticosteroids exceeding equivalent of daily 15 mg oral prednisone or 30 mg every other day
7. Adequate liver and kidney function as determined by lab tests