Official Title

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

    Phase 3
  • Study Type

  • Status

  • Study Participants

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.
This is a multi-center, randomized, double-blind, placebo-controlled trial of NAC or placebo in about 200 participants with IPF with a TOLLIP rs3750920 TT genotype.

Eligible participants will be randomized in a 1:1 fashion to NAC or placebo, stratified by stable concomitant IPF therapy use (i.e., pirfenidone or nintedanib administered for at least 6 weeks prior to screening) versus no pirfenidone or nintedanib use. Participants will receive 600 mg NAC orally or matched placebo to take three times daily for 24 months.
Study Started
Dec 17
Primary Completion
Sep 15
Study Completion
Sep 15
Last Update
Jul 27

Drug N-acetyl cysteine

600 mg N-acetylcysteine (NAC) oral tablets three times daily for 24 months.

  • Other names: NAC

Drug Placebo

Matching oral placebo tablet three times daily for 24 months.

N-acetylcysteine Experimental

600 mg oral N-acetylcysteine (NAC) three times daily for 24 months.

Placebo Placebo Comparator

Placebo tablet three times daily for 24 months.


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
No Results Posted