Rein Therapeutics, Inc.

Rein Therapeutics, Inc. is a clinical-stage biopharmaceutical company developing novel therapies for orphan pulmonary and fibrosis indications that currently have no approved or limited effective treatments. The company has two product candidates in clinical development, LTI-03 and LTI-01. Due to insufficient funding, development of LTI-01 has been paused for an undetermined period, and the company is prioritizing LTI-03. LTI-03 is a peptide in development for Idiopathic Pulmonary Fibrosis (IPF), a progressive and fatal lung disease with a median survival of three to five years from diagnosis, affecting approximately 100,000 people in the U.S. LTI-03 has demonstrated the ability to protect healthy lung epithelial cells and reduce pro-fibrotic signaling. A Phase 1b dose-ranging, placebo-controlled trial evaluated its safety, tolerability, and pharmacodynamic biomarker activity. LTI-03 has received Orphan Drug Designation in the U.S. and the European Union for IPF. LTI-01 is a proenzyme that completed a Phase 2a dose-ranging, placebo-controlled trial and a Phase 1b safety, tolerability, and proof of mechanism trial in loculated pleural effusion (LPE) patients, an indication with no approved drug treatment. In June 2024, the company temporarily delayed clinical development of LTI-01 to focus resources on LTI-03 until additional funds are raised. In the fourth quarter of 2024, it was determined that this delay might not be short-term. In the fourth quarter of 2025, development activities for LTI-01 and preclinical programs targeting cystic fibrosis and a peptide program focused on the Cav1 protein for systemic fibrosis indications were paused indefinitely.