LA JOLLA, CA. — GRI Bio, Inc. (NASDAQ: GRI) (“GRI Bio” or the “Company”), a biotechnology company advancing an innovative pipeline of immune cell modulators for the treatment of inflammatory, fibrotic and autoimmune diseases, today announced positive flow cytometry data from the Phase 2a GRI-0621-IPF-02 clinical trial evaluating GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (“IPF”). Immune cell samples from lung bronchoalveolar lavage (BAL) fluid and peripheral blood mononuclear cells (PBMC) demonstrated iNKT inhibition and a clear immunomodulatory shift towards an anti-fibrotic profile, producing more anti-fibrotic interferon-gamma (IFN-γ) and less pro-fibrotic interleukin-4 (IL-4), IL- 13, IL-17A, IL-22, and transforming growth factor-beta (TGF-β).
Chronically activated iNKT cells downregulate the expression of their T cell receptor (TCR). GRI- 0621-treated subjects demonstrated increased TCR expression after 12 weeks of treatment compared with baseline or placebo-treated subjects receiving standard of care. T cell subsets demonstrated increased type I-associated cytokines (IFN-γ) and reduced type 2 (IL-4 and IL-13) and type 3-associated cytokines (IL-17A and IL-22) in both BAL and PBMC samples. Similarly, TGF-β was observed to be reduced after 12 weeks of GRI-0621 treatment in T cell subsets (e.g. Treg and Treg-like), B cells, monocytes, macrophages and neutrophils in BAL and PBMC samples compared to baseline or placebo-treated subjects receiving standard of care.
“There remains a tremendous unmet need for safe, tolerable, and truly effective treatments for patients suffering from IPF,” said Marc Hertz, PhD, Chief Executive Officer of GRI Bio. “GRI-0621 continues to demonstrate a compelling profile, combining favorable safety and tolerability with a dual mechanism of action as both an immunomodulator and an anti-fibrotic agent.”
“Our Phase 2a study was intentionally designed to assess a broad range of clinical, biomarker, and mechanistic endpoints,” Dr. Hertz continued. “The immune cell data announced today are highly consistent with our earlier findings on collagen turnover, lung tissue repair, and improvements in pulmonary function, further strengthening the overall clinical proof-of-concept for GRI-0621.”
The Company previously reported that the study met its primary endpoint, demonstrating a safety and tolerability profile differentiated from that of existing treatment options. The study also met secondary endpoints suggestive of disease-modifying activity, reversal of fibrosis and inducement of a lung repair mechanism, as well as exploratory endpoints demonstrating increased forced vital capacity (FVC) with twice as many subjects observed to have no decline in FVC compared to standard of care alone at 12 weeks of treatment.
The Phase 2a, randomized, double-blind, multinational, multi-center, placebo-controlled, parallel- design, 2-arm study enrolled 35 subjects with IPF who were randomized in a 2:1 ratio for GRI- 0621 4.5mg or a placebo. GRI-0621 dose of 4.5mg was compared with a dose of placebo following once daily oral administration for 12 weeks. Concurrently, a sub-study examined the number and activity of immune cells in bronchoalveolar lavage (“BAL”) fluid in 8 subjects (across various centers). The primary endpoint for the Phase 2a study was safety and tolerability of oral GRI-0621 as assessed by clinical labs, vital signs and adverse events after 12 weeks of treatment. Secondary endpoints were baseline changes in serum biomarkers collected at week 6 and week 12; an assessment of the pharmacokinetics (PK) of GRI-0621 at the week 12 visit of treatment (steady state); and a determination of the pharmacodynamic activity of oral GRI-0621 as measured by inhibition of immune cell activation in blood after 6 weeks and 12 weeks, and from BAL fluid after 12 weeks of treatment in the sub-study. Additional exploratory endpoints for the study included assessment of the effect of GRI-0621 on pulmonary function at baseline and after 6 weeks and 12 weeks of treatment and flow cytometry and differential gene expression at various time points. These results show that GRI-0621’s receptor selectivity is consistent with the toxicity profile observed in earlier studies evaluating oral tazarotene in over 1,700 patients treated for up to 52 weeks.
For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624.
The Company also previously announced that it successfully completed a public offering in early December 2025. As a result of this offering and as of the date of this press release, the Company believes its stockholders’ equity is in excess of the minimum $2.5 million Nasdaq requirement.
About GRI Bio, Inc.
GRI Bio is a clinical-stage biopharmaceutical company focused on fundamentally changing the way inflammatory, fibrotic and autoimmune diseases are treated. GRI Bio’s therapies are designed to target the activity of Natural Killer T (“NKT”) cells, which are key regulators earlier in the inflammatory cascade, to interrupt disease progression and restore the immune system to homeostasis. NKT cells are innate-like T cells that share properties of both NK and T cells and are a functional link between the innate and adaptive immune responses. Type I invariant NKT (“iNKT”) cells play a critical role in propagating the injury, inflammatory response, and fibrosis observed in inflammatory and fibrotic indications. GRI Bio’s lead program, GRI-0621, is an RARβγ agonist shown to inhibit the activity of key immune cells, like iNKT cell activity, and is being developed as a novel oral therapeutic for the treatment of idiopathic pulmonary fibrosis, a serious disease with significant unmet need. The Company is also developing a pipeline of novel type 2 diverse NKT (“dNKT”) agonists for the treatment of systemic lupus erythematosus. Additionally, with a library of over 500 proprietary compounds, GRI Bio has the ability to fuel a growing pipeline.
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