A Study to Access Activity and Safety With SAR445399 Compared With Placebo in Participants Aged 18 to 80 Years of Age With Non-Cystic Fibrosis Bronchiectasis

Inclusion Criteria: * Participants must be 18 to 80 years of age inclusive, at the time of signing the informed consent * Clinical history consistent with NCFB, such as chronic productive cough and/or recurrent respiratory infections * Documented evidence of at least 2 PEx defined as episodes requiring a physician-prescribed course of antibiotics (oral and/or IV) for ≥5 days for signs and symptoms of respiratory infection within the 12 months prior to the Screening Visit * Radiologic evidence of bronchiectasis, confirmed by a chest HRCT * A minimum MPS of 4 (out of maximum 18) on chest HRCT performed before Baseline Visit * Current sputum production with a documented history of chronic expectoration lasting ≥3 months within the previous 12 months * Participants must have a post-bronchodilator FEV1 ≥30% of predicted normal value Exclusion Criteria: * A primary diagnosis of smoking-related COPD or asthma as determined by the Investigator. Participants with comorbid smoking-related COPD may be included if bronchiectasis is confirmed as their primary diagnosis and is the predominant cause of their respiratory symptoms * Diagnosis of ABPA or any of the allergic bronchopulmonary mycoses * Active NTM lung infection or incomplete NTM treatment course * Bronchiectasis due to any of the following: CF, CVID, AAT or PCD * History of significant hemoptysis (requiring medical intervention and/or requiring blood transfusion) * Current tobacco smokers * Known or suspected immunosuppressio…