Evaluating N-Acetylcysteine in CTD-ILD Treatment (ENACT)

Inclusion Criteria:

• Subject has been diagnosed with a connective tissue disease and associated interstitial lung disease confirmed by high resolution computed tomography of the lungs along with symptoms of cough and/or shortness of breath.
• Males and females age greater than 18 years at time of screening.
• Females of childbearing potential must be willing to use a reliable form of medically acceptable contraception and have a negative pregnancy test confirmed at baseline before starting NAC as per standard of care. Women who are surgically sterile or have been post-menopausal for at least two years are not considered to be of child-bearing potential.
• Subject is able to return for assessments every three months for one year.
• Pulmonary function studies completed within the last 12 weeks demonstrating FVC less than 90% of the predicted value.
• An FVC decline of 5-15% between screening PFT and PFT prior to screening.

Exclusion Criteria:

• History of severe chronic kidney disease defined as a GFR less than 30.
• Hemoglobin concentration less than 70% of the lower limit of the normal range at time of screening.
• Moderate to severe hepatic impairment, i.e., Child-Pugh Class B or C.
• Concurrent use of nitroglycerin.
• Significant comorbidities interfering with respiratory status, i.e., congestive heart failure, pulmonary hypertension, cancer, COPD.
• High resolution computed tomography demonstrating a pulmonary disease other than interstitial lung disease as the predominant pulmonary abnormality.
• Patients considered to have stable, fibrotic lung disease without active inflammation per the investigators.
• History of noncompliance with recommended medical therapy, or is determined to be a poor study candidate by the investigators.