GRI-0621-IPF-02

September 8, 2026: GRI Bio (NASDAQ: GRI) reported new translational biomarker, exploratory lung function, and safety data from the Phase 2a GRI-0621-IPF-02 trial of GRI-0621 (oral tazarotene; RARβ/γ-selective agonist) in idiopathic pulmonary fibrosis, presented in a late-breaking oral presentation and three posters at the 2026 ERS Congress.

In the 35-patient randomized, double-blind, placebo-controlled study, safety was the primary endpoint. Across RNA sequencing, serum ECM biomarkers, spectral flow cytometry, and clinical readouts, the company said all nine pre-specified mechanistic pillars were supported, including immune re-balancing, myofibroblast inhibition, fibrolysis, basement-membrane repair, re-epithelialization, FVC stabilization, antitussive effect, and GI protection. Eighteen of 72 anchor transcripts reached FDR<0.05 and 13 flow cytometry readouts reached p<0.05.

Exploratory Week 12 lung function showed placebo-adjusted FVC change of +99 mL overall and +139 mL on background antifibrotic therapy; 39% of treated patients had FVC increase ≥30 mL vs 20% on placebo, and 8% had FVC decline ≥10% vs 20% on placebo. Ten post hoc sensitivity analyses remained directionally positive.

GRI-0621 was reported as well tolerated over 12 weeks, with no serious treatment-emergent adverse events in the active arm versus 8% on placebo. The company said the data support advancing GRI-0621 into a longer, 52-week IPF study.