The objectives of this Phase 1/2 prospective interventional trial are to: 1. Evaluate the safety, tolerability, and immunogenicity of a single dose of 4D-710 delivered via nebulization 2. Identify a recommended phase 2 dose (RP2D) for further evaluation 3. Evaluate 4D-710 target gene transduction/expression in bronchoscopic samples (Dose Exploration) and durability of expression (Dose Expansion) 4. Evaluate the impact of 4D-710 on pulmonary function (FEV1) and complications associated with CF lung disease 5. Evaluate the impact of 4D-710 on health-related quality of life (HRQOL) Primary outcome variables are: Incidence and severity of TEAEs, serious adverse events (SAEs), and DLTs including clinically significant changes from baseline to scheduled time points in safety parameters Secondary outcome variables are: 1. Maximum % change in FEV1 from baseline after 4D-710 administration (Month 2 to Month 12) 2. Change in percent predicted FEV1 (ppFEV1) from baseline (Month 2 to Month 12) 3. Time from baseline to first pulmonary exacerbation 4. Number of subjects with 1 pulmonary exacerbation through Month 12 5. Change from baseline in Cystic Fibrosis Questionnaire-revised (CFQ-R) scores for each domain by timepoint 6. Development and persistence of ADA to 4D-710 capsid proteins and CFTR 7. Gene transfer and expression in bronchoscopy samples as measured by quantitative

You may be eligible for this study if you meet the following criteria:

• Conditions: Medical Research
• Age: - 99 Years
• Gender: All