Key Inclusion Criteria:  Has a diagnosis of Nontuberculous Mycobacterial pulmonary disease caused by MABc Has at least 2 of the following NTM-infection symptoms present at Screening and Baseline: chronic cough, coughing up blood (hemoptysis), wheezing, chest pain, frequent throat clearing, phlegm or sputum production, shortness of breath, fatigue, fever, night sweats, poor appetite, and/or weight loss. At least 1 positive pulmonary (sputum) culture for MABc in the 6 months prior to Screening and 1 positive culture at Screening Radiographic evidence of MABc infection via computed tomography (CT) scan of the chest within 3 months prior to Screening In the opinion of the investigator, guideline-directed antibiotic therapy for treatment of MABc will not be required within the next 3 months, and a delay, in order for the subject to participate in a placebo-controlled clinical trial, is considered reasonable and clinically acceptable Additional inclusion criteria as per protocol  Key Exclusion Criteria:  Has received antibiotic treatment within 6 months prior to Screening for MABc or MAC Has received systemic or inhaled antibiotic therapy (other than chronic macrolide therapy) within 4 weeks prior to Screening Has any of the following medical conditions: Active pulmonary malignancy, or any type of malignancy requiring chemotherapy or radiation within 1 year prior to Screening Active allergic bronchopulmonary mycosis, or any other condition requiring chronic treatment with systemic corticosteroids within 90 days prior to Screening Radiologic evidence of cavitary disease Known active pulmonary tuberculosis Cystic fibrosis History of lung transplantation Another advanced lung disease with a known percent predicted forced expiratory volume in 1 second < 30%. Disseminated or extra-pulmonary NTM disease Has been previously treated with omadacycline Has a history of hypersensitivity or allergic reaction to tetracyclines Additional exclusion criteria as per protocol