A Study of 24 to 52 Weeks Treatment to Evaluate The Efficacy And Safety of Galvokimig in Adult Study Participants With Non-Cystic Fibrosis Bronchiectasis (ATMOS)

Inclusion Criteria:

• Participant must be 18 to ≤80 years of age, inclusive, at the time of signing the informed consent form (ICF)

• Participant with a documented history of Non-Cystic Fibrosis Bronchiectasis (NCFB) (cough, chronic sputum production, and/or recurrent respiratory infections) confirmed by high resolution computed tomography (HRCT) demonstrating bronchiectasis in 1 or more lobes. Confirmation of diagnosis via HRCT will be performed as close as possible to, and within 7 calendar days of the Baseline visit, in all participants who meet all inclusion criteria and no exclusion criteria at Screening. Central reading confirmation, where images are evaluated by independent centralized experts, is required before the participant is randomized

• Participant with a history of chronic expectoration who are current sputum producers and are able to provide spontaneous sputum sample at Screening. If the participant is unable to produce spontaneous sputum at Screening, the participant will be considered a screening failure and may be rescreened once

• Participant with a history of at least 2 moderate or severe pulmonary exacerbations within the past 12 months prior to Screening or 1 severe pulmonary exacerbation within 6 months prior to Screening

• Participant with post- Bronchodilator (BD) forced expiratory volume (FEV) 1% predicted ≥30% at Screening and Baseline

• Participant has acceptable inhaler (where applicable) and spirometry techniques according to American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines during the Screening Visit. Participants who do not meet such criteria can be repeated once without being rescreened

• Participant can be male or female

• A male participant must agree to use contraception during the Intervention Period and for at least 60 days after the final dose of study intervention, and refrain from donating sperm during this period

• A female participant is eligible to[ participate if she is not pregnant, not breastfeeding (including pumping breastmilk to feed a child), and at least 1 of the following conditions applies:

  • Not a woman of childbearing potential (WOCBP) OR
  • A WOCBP who agrees to follow the contraceptive guidance during the Intervention Period and for at least 60 days after the final dose of study intervention

Exclusion Criteria:

• Participant has any history or presence of any medical or psychiatric condition, physical examination finding, laboratory test result, or Electrocardiogram (ECG) signal that, in the opinion of the investigator, could constitute a risk when taking the study intervention; or interfere with the interpretation of data and could jeopardize or would compromise the study participant's ability to participate in this study

• Participant has a presence or family history (first degree) of inflammatory bowel disease (IBD) (includes Crohn's disease and ulcerative colitis)

• Participant has a history of chronic or recurrent clinically significant infections, or a serious extrapulmonary infection within 6 months prior to the Baseline, as judged by the investigator.

• Participant is not permitted to enroll into the study if they meet any of the following Tuberculosis (TB) exclusion criteria:

  • Known active TB disease.
  • History of active TB involving any organ system unless adequately treated according to World Health Organization/Centers for Disease Control and Prevention therapeutic guidance and proven to be fully recovered upon consultation with an appropriate relevant specialist
  • Latent tuberculosis infection (LTBI) (unless a course of appropriate preventative therapy has been completed prior to study intervention dosing). TB preventive therapy should be in accordance with applicable clinical guidelines and appropriate specialist judgment based on the origin of the infection
  • High risk of acquiring TB infection

• Participant has clinically important pulmonary disease other than NCFB as judged by the investigator.

• Participant has an acute infection (including pulmonary infection) requiring antibiotics, systemic corticosteroids, or antiviral medication within 4 weeks prior to Screening (and in the Screening Period) based on the final day of antibiotic/antiviral/systemic steroid treatment or hospitalization discharge date, whichever occurred later. A participant who suffers from a pulmonary exacerbation during the Screening Period, prior to randomization, is considered a screen failure. Rescreening is allowed once following resolution of the pulmonary exacerbation

• Participant has bronchiectasis known to be due to lung fibrosis, cystic fibrosis, hypogammaglobulinemia, common variable immunodeficiency disorders or α1-antitrypsin deficiency

• Participant has a primary diagnosis of Chronic Obstructive Pulmonary Disease (COPD) or asthma. A secondary diagnosis is allowed

• Participant has significant hemoptysis defined as ≥300mL or requiring blood transfusion within 6 weeks from Screening

• Participant has a history of lung transplantation

• Study participant has an absolute neutrophil count (ANC) <1.5×10^3/μL. This test can be repeated once