A Study to Evaluate the Efficacy, Safety, Tolerability, and Pharmacokinetics of SPR720 as Compared With Placebo for the Treatment of Participants With Mycobacterium Avium Complex (MAC) Pulmonary Disease

Inclusion Criteria:

1. Has a prior diagnosis of NTM-PD due to MAC according to American Thoracic Society (ATS) criteria

2. Has at least one prior lower respiratory culture (sputum or bronchoalveolar lavage [BAL]) positive for MAC in the 12 months prior to consent

3. Has an induced sputum culture at Screening positive for MAC by quantitative cultureon solid agar

4. Is either treatment naïve and has not received any prior treatment for MAC, OR ifpreviously treated for MAC and meets all of the following criteria:

5. Has a history of successful treatment with sputum culture conversion tonegative

6. Has recent sputum or BAL culture evidence of recurrent or relapsed disease and

7. Has been off therapy for at least 3 months prior to consent

8. Has clinical signs and symptoms within the 6 weeks prior to consent that areconsistent with NTM-PD with ≥2 of the following:

9. chronic cough

10. fatigue

11. frequent throat clearing

12. shortness of breath (dyspnea)

13. coughing up of blood (hemoptysis)

14. excessive mucus (sputum) production

15. fever (temperature >38ºC or >100.4ºF)

16. night sweats

17. loss of appetite

18. unintended weight loss

19. wheezing

20. chest pain

21. Has a measured forced expiratory volume in the first second following maximalinhalation (FEV1) % predicted ≥30% within 3 months prior to consent. If prior FEV1%predicted test result is not available, obtain FEV1% predicted at Screening toconfirm eligibility

Exclusion Criteria:

1. In the opinion of the Investigator, is not a candidate for a 5-month delay ininitiation of standard multidrug therapy to participate in a placebo-controlledclinical trial (e.g., participant has severe symptoms or, extensive disease burden)

2. Has disseminated or extrapulmonary NTM disease

3. Has end-stage NTM-PD or treatment-refractory NTM-PD

4. Has isolation on lower respiratory (sputum or BAL) cultures of any Mycobacteriumspecies other than those included in MAC within the 6 months prior to consent

5. Has any other condition or prior therapy, which, in the opinion of the Investigator,would make the participant unsuitable for this study, including compliance with allstudy assessments and adherence to the protocol schedule of assessment

6. Prior exposure to SPR720. Participants who are unable to comply with therequirements of the study or who in the opinion of the Investigator should notparticipate in the study are not eligible

• Other inclusion and exclusion criteria as per protocol may apply.