Inclusion Criteria;

• Male or female, ≥ 18 years of age (20 years or older in Japan).
• Current diagnosis of MAC lung infection (initial, second, or third infection event). MAC or mixed infection with MAC as the dominant species allowed, with MAC as the intended organism for treatment.
• Positive sputum culture for MAC within 6 months prior to Screening.
• Positive sputum culture for MAC at Screening.
• A high-resolution chest computed tomography (CT) scan or chest CT scan with contrast, read locally, within 6 months prior to Screening. Subjects who do not have a chest CT scan within 6 months prior to Screening will be required to obtain a high-resolution chest CT scan or chest CT scan with contrast, read locally, during Screening.
• In the Investigator’s opinion, documented respiratory signs/symptoms at Screening that are attributable to the current MAC lung infection.
• An average QOL-B respiratory domain score of ≤ 85 based on scores at Screening and on the day of enrollment prior to randomization.
• In the Investigator’s opinion, underlying lung disease (eg, chronic obstructive pulmonary disease [COPD], bronchiectasis) have been managed according to best local standard of care, and on stable maintenance therapy for a minimum of 4 weeks prior to randomization.
• Adherence to a predefined multidrug antimycobacterial regimen during the study.
• Ability to produce (spontaneously or with induction) approximately 2 mL of sputum for mycobacteriology at Screening.
• Women of child-bearing potential (WOCBP) agree to practice an acceptable method of birth control (eg, true abstinence [refraining from heterosexual intercourse during the entire study], copper intrauterine device [IUD], hormonal methods (levonorgestrel-releasing intrauterine system, progestogen implant, combined oral contraceptive pill [combined with barrier method] or double barrier method plus a spermicidal agent, exclusive homosexual relationship, or sole male partner who has undergone surgical sterilization with confirmation of azoospermia at least 3 months post procedure) while participating in the study.
• Provide signed informed consent prior to administration of study drug or performing any study related procedure.
• Be able to comply with study drug use, study visits, and study procedures as defined by the protocol.

Exclusion Criteria

• Diagnosis of cystic fibrosis (CF).
• History of 3 or more prior MAC lung infections.
• Received any mycobacterial antibiotic treatment for current MAC lung infection.
• Refractory MAC lung infection, defined as having positive MAC cultures while being treated with a multidrug mycobacterial antibiotic treatment regimen for a minimum of 6 consecutive months and no documented successful treatment, defined as negative sputum culture for MAC and cessation of treatment
• Relapse of prior MAC lung infection, defined as positive sputum culture for MAC ≤ 6 months of cessation of prior successful treatment.
• MAC isolate with MIC for liposomal amikacin ≥ 128 μg/mL at Screening.
• Evidence of any pulmonary cavity ≥ 2 cm in diameter, as determined by chest CT scan, read locally, within 6 months prior to Screening.
• Radiographic finding of new lobar consolidation, atelectasis, significant pleural effusion, or pneumothorax during routine clinical care within 2 months prior to Screening.
• Active pulmonary malignancy (primary or metastatic) or any malignancy requiring chemotherapy or radiation therapy within 1 year prior to Screening or anticipated during the study.
• Active pulmonary tuberculosis requiring treatment during Screening
• Hospitalization for underlying lung disease during Screening..
• Acute pulmonary exacerbation (e.g., COPD or bronchiectasis) requiring treatment with antibiotics, or corticosteroids (IV or oral), within 4 weeks prior to and during Screening.
• Predicted forced expiratory volume in 1 second (FEV1) < 35%, pre-bronchodilator use.
• Current smoker.
• History of lung transplantation.
• Use of inhaled or systemic aminoglycosides with activity against MAC (eg, amikacin, kanamycin, or streptomycin) during Screening.
• Prior exposure to ALIS (including clinical study).
• Known hypersensitivity to aminoglycosides.
• Disseminated MAC infection.
• Positive pregnancy test or lactation at Screening. All WOCBP will be tested. Women not of childbearing potential are defined as postmenopausal (ie, amenorrheic for 12 months without an alternative medical cause), or naturally or surgically sterile through bilateral oophorectomy, hysterectomy, or bilateral salpingectomy. For women under the age of 45, confirmatory testing with follicle stimulating hormone should be considered).
• Administration of any investigational drug within 8 weeks prior to Screening.
• Acquired and primary immunodeficiency syndromes (eg, HIV-positive, regardless of CD4 counts).
• Significant (as determined by the Investigator) hearing loss, vestibular dysfunction, neuromuscular weakness or a diagnosis of myasthenia gravis, where the potential risk of aminoglycoside toxicity outweighs the potential benefit.
• Aspartate aminotransferase or alanine aminotransferase ≥ 3 times the upper limit of normal (ULN) or total bilirubin ≥ 2 times ULN at Screening.
• Absolute neutrophil count ≤ 500/μL at Screening.
• Serum creatinine > 2 times ULN at Screening.
• Current alcohol, medication, or illicit drug abuse.
• Any condition that, in the opinion of the Investigator, interferes with ability to safely complete the study or adhere to study requirements.