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


About this study

The purpose of this study is to compare the effect of n-acetylcysteine (NAC) plus standard care with matched placebo plus standard of care in patients diagnosed with idiopathic pulmonary fibrosis (IPF) who have the TOLLIP rs3750920 TT genotype. The study will compare the time to a composite endpoint of relative decline in lung function [10% relative decline in forced vital capacity (FVC), first respiratory hospitalization, lung transplantation, or all-cause mortality] The secondary objectives will be to examine the effect of NAC on the components of the primary composite endpoint, the rates of clinical events, change in physiology, change in health status, and change in respiratory symptoms.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

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.

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

Andrew Limper, M.D.

Open for enrollment

Contact information:

Shannon Daley C.C.R.C., CCRP

(507) 293-0637

More information


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