Metformin to Attenuate Progressive Respiratory Decline in Idiopathic Pulmonary Fibrosis

This is a multi-center, randomized, double-blind, placebo-controlled trial, of metformin or placebo in 400 participants with idiopathic pulmonary fibrosis (IPF) who are at high risk of adverse clinical outcomes based on a proteomic classifier. Eligible participants will be placed into 2 groups depending on the results of their proteomic signature blood test done at the Screening Visit (Visit 0). * Eligible participants who have the proteomic signature present will be randomized in a 1:1 fashion to either metformin at Visit 1 (Enrollment/Baseline) and attend follow-up visits at Months 1, 3, 6, 12, 18, 24, and a follow-up phone call at 25 months. Randomization will be stratified by background FDA-approved IPF therapy (yes/no) and DM status (yes/no). * Eligible participants who are proteomic signature absent will be asked to complete 2 follow-up remote visits at Months 12 and 24. The metformin starting dose will be 500 mg daily of extended-release formulation or matching placebo. The dose will be increased by 500 mg every 14 days to a total target daily dose of 1500 mg. Participants will be followed for a minimum of 12 months and a maximum of approximately 25 months, depending on the date of randomization.