This is a randomized, Phase 2a, double-blind, placebo-controlled study to evaluate the safety and efficacy of ARINA-1 compared to placebo (isotonic saline, 0.9%) in participants with NCFBE. Study participants will receive either study treatment or placebo twice daily for 28 days. Efficacy endpoints will include quality of life, sputum rheological markers, and blood inflammatory markers. Quality of life will be measured using the following tools: Quality of Life-Bronchiectasis (QOL-B) questionnaire, St. George's Respiratory Questionnaire (SGRQ), Chronic Airways Assessment Test (CAAT), and a daily clinical global impression questionnaire.

Inclusion Criteria:

• Diagnosis of NCFBE confirmed by chest CT
• 18-80 years old, inclusive at time of informed consent
• BMI >18
• Percent predicted FEV1 > 40%, pre-bronchodilator
• Stable for 90 days with any airway clearance technique (ACT) method(s)
• Stable on standard of care (SOC) therapy for 90 days (includes cycling antibiotics, such as inhaled tobramycin, and long-term macrolide therapy) and not likely, in the opinion of the investigator, to require any changes to therapy during the duration of study participation
• Fully vaccinated for COVID-19 (second dose of a 2-shot regimen or single dose of 1-shot regimen completed >14 days prior to the screening visit)
• Must be able to produce a sputum sample
• If female and of childbearing potential, must be willing to use contraception for the duration of the study.

Exclusion Criteria

• Positive urine pregnancy test for women of childbearing potential (WOCBP) at screening and baseline visit
• Active exacerbation ≤28 days prior to the baseline visit
• Initiating or changing antibiotic, antiviral, or antifungal therapy ≤ 28 days prior to the baseline visit
• Changing or initiating any vitamin C, glutathione or N-acetyl-cysteine-containing therapy or multivitamin within 30 says prior to the screening visit.
• Positive COVID-19 diagnostic test (PCR or antigen) within 90 days prior to the screening visit.
• Participated in other interventional drug or device studies within 30 days of the screening visit (Note: observational studies are acceptable)
• Significant unstable comorbidities (in the opinion of the site investigator), such as heart failure, cardiovascular disease, diabetes, renal disease, liver disease
• Current tobacco or marijuana smoker (those with active smoking exposure <180 days prior to the screening visit) (Note: edibles are acceptable)
• Requiring the use of any supplemental oxygen
• Currently on cycled antibiotics (e.g., tobramycin) or have been on a cycled antibiotic regimen within 90 days prior to the screening visit.
• Current diagnosis of non-tuberculous mycobacteria (NTM) requiring antibiotic treatment. (Participants who test positive for NTM but who are not currently on antibiotic therapy are eligible for screening)