Prospective Treatment Efficacy in IPF Using Genotype for Nac Selection (PRECISIONS) Trial

Inclusion Criteria: * ≥ 40 years of age * Diagnosed with IPF according to 2018 ATS/ERS/JRS/ALAT, confirmed by enrolling investigator * Signed informed consent * If taking pirfenidone or nintedanib, must be on stable dose for at least 6 weeks prior to enrollment visit * Confirmed rs3570920 TT TOLLIP genotype Exclusion Criteria: * Pregnancy or planning to become pregnant * Women of childbearing potential not willing to remain abstinent (refrain from heterosexual intercourse) or use two adequate methods of contraception, including at least one method with a failure rate of \<1% per year during study participation * Significant medical, surgical or psychiatric illness that in the opinion of the investigator would affect subject safety, including liver and renal failure * Receipt of an investigational drug or biological agent within the previous 4 weeks of the screening visit or 5 times the half-life, if longer * Supplemental or prescribed NAC therapy within 60 days of enrollment * Listed for lung transplantation at the time of screening * History of lung cancer * Inability to perform spirometry * Forced vital capacity (FVC) less than 45% predicted, using the global lung function index (GLI) equation at Visit 1 * Active respiratory infection requiring treatment with antibiotics within 4 weeks of Visit 1