GRI Bio presents new Phase 2a data on GRI-0621 in IPF

GRI Bio, Inc. (NASDAQ: GRI) presented new translational biomarker data from its Phase 2a GRI-0621-IPF-02 study at the 2026 European Respiratory Society Congress in Barcelona, Spain, on September 8, 2026. The data were presented as a late-breaking oral presentation and three posters, and they cover GRI-0621 in idiopathic pulmonary fibrosis (IPF). The company announced the results in an exhibit to its Form 8-K.

Nine mechanistic pillars

GRI Bio describes itself as a biotechnology company developing innovative therapies for inflammatory, fibrotic and autoimmune diseases. The company said the findings integrate, for the first time, four independent measurement modalities from the same 35-patient study population.

The study population was 35 patients. The company combined four measurement methods: whole-blood RNA sequencing of 72 curated anchor genes, an expanded 12-marker serum extracellular matrix panel, 28-color spectral flow cytometry of paired blood and bronchoalveolar lavage samples, and clinical and patient-reported readouts. Eighteen anchor transcripts reached statistical significance. The company says the evidence resolves into nine pillars: immune re-balancing, reduced lung injury, myofibroblast inhibition, fibrolysis, basement-membrane repair, re-epithelialization, FVC stabilization, antitussive effect and gastrointestinal protection. Each pillar is supported by direction-consistent signals from at least two independent measurement methods.

Among the findings, the company reported a shift away from a pro-fibrotic Th2 response, reduced TGF-β and ROCK2 pathway activity, and a net shift toward breakdown of fibrillar collagen. It also reported a concordant signal of basement-membrane repair, with a net gain in type IV collagen at the gene and protein level.

Lung function and safety

At Week 12, 39% of GRI-0621-treated patients had an FVC increase of 30 mL or more, compared with 20% on placebo. The rate rose to 50% among patients receiving background standard-of-care antifibrotic therapy, which the company describes as approximately 2x to 2.5x the placebo responder rate. Only 8% of GRI-0621-treated patients had an FVC decline of 10% or more, against 20% on placebo.

Placebo-adjusted FVC change from baseline at Week 12 was +99 mL overall and +139 mL on background standard-of-care therapy. The company ran ten post hoc sensitivity analyses, and their estimates converged on +40 to +65 mL overall and +67 to +89 mL in the background subset. The company says FVC was an exploratory endpoint and that the study was not powered for statistical significance. In other words, 35 patients, a 12-week window and post hoc re-analyses cannot show that the lung function gain is real. The release gives no p-values or confidence intervals for the FVC figures, and the biomarker pillars are signals in blood and lavage samples, not proof that lung structure was rebuilt.

The company reported no serious treatment-emergent adverse events in the GRI-0621 arm, against 8% on placebo. Treatment-emergent cough occurred in 0% of GRI-0621 patients, against 25% on placebo, and diarrhea in 17%, against 33%. Dyspnea was 4%, against 17% on placebo, and weight loss was 0%, against 17%, despite higher background nintedanib use in the GRI-0621 arm. Adverse events were consistent with the known retinoid class profile, including dry lips, dry skin, arthralgia and myalgia, all Grade 1 to 2 and managed with routine supportive care. The company reported no clinically meaningful changes in liver enzymes, triglycerides or LDL cholesterol.

Marc Hertz, PhD, the chief executive officer, said: "Approved antifibrotics slow lung function decline but have not been shown to rebuild lung architecture."

What comes next

The company said the totality of its Phase 2a findings supports advancing GRI-0621 in the IPF program and further evaluation in a longer-duration study. It has not said how that study would be designed or paid for. The financial data show a net loss of $12.0 million for 2025, cash used in operations of $10.2 million, and cash and cash equivalents of $10.9 million at June 30, 2026. The 10-K lists the company's ability to continue as a going concern and to stay listed on the Nasdaq Capital Market among its risks, and it describes the company as needing substantial additional capital. The sources show no financing announced for a longer study.

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