GRI Bio’s Interim Biomarker Data Demonstrate Positive Trend Toward Anti-Fibrotic Effect of GRI-0621 in First 12 Patients of Ongoing Phase 2a Study in Idiopathic Pulmonary Fibrosis

GRI Bio, Inc. recently reported interim biomarker results from its ongoing Phase 2a study evaluating GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (“IPF”). Additionally, management participated in a Virtual Investor “What This Means” segment to discuss the interim biomarker data. The segment is now available here.

The IDMC has examined the change from baseline biomarkers from the first 12 subjects at 2 weeks and determined the change from baseline in PRO-C3 of GRI-0621-treated patients compared to placebo patients is suggestive of anti-fibrotic effect. Based on the available interim data reviewed, the IDMC has recommended the Phase 2a study evaluating GRI-0621 to continue as planned as there are no safety concerns seen to date.

“While still early and in a small number of subjects, the trend in anti-fibrotic effect seen with GRI-0621 is very encouraging. We believe that these data, in combination with the early safety data and consistent toxicity profile with tazarotene, underscores GRI-0621’s potential to provide a safe and effective treatment option that inhibits NKT cell activity in this patient population, providing much needed benefit to patients,” commented Marc Hertz, PhD, Chief Executive Officer of GRI Bio. “We have also completed enrollment for the 6-week interim data, and with almost 70% of the total study subjects enrolled, we remain on track to report topline data in the third quarter of 2025.”

The Phase 2a, randomized, double-blind, multi-center, placebo-controlled, parallel-design, 2-arm study will enroll approximately 36 subjects with IPF whom will be randomized in a 2:1 ratio for GRI-0621 4.5mg or a placebo. GRI-0621 dose of 4.5mg will be compared with a dose of placebo following once daily oral administration for 12 weeks. Concurrently, a sub-study will examine the number and activity of NKT cells in bronchoalveolar lavage (“BAL”) fluid for up to 12 eligible subjects (across various centers). An interim analysis will be performed when 24 subjects (of which approximately 8 will be placebo subjects) complete 6 weeks of treatment. The primary endpoint for the study is safety and tolerability of oral GRI-0621 as assessed by clinical labs, vital signs and adverse events after 12 weeks of treatment. Secondary endpoints are 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 iNKT cell activation in blood after 6 weeks and 12 weeks, and from BAL fluid after 12 weeks of treatment in a sub-study. Additional exploratory endpoints for the study are to assess 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.

As previously announced, the pre-planned interim analysis for 2-week safety results from the ongoing Phase 2a biomarker study demonstrated GRI-0621 (4.5mg orally once daily) to be safe and well-tolerated in the first 12 patients evaluated per protocol. Hyperlipidemia, as assessed by LDL, HDL and triglyceride (TG) levels, was not seen in the 12 patients assessed at the 2-week visit. There were no meaningful changes in HDL, LDL or TG levels in patients receiving GRI-0621, and all subjects remained within normal ranges. The interim analysis committee recommended the study should continue as planned. The interim 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.

Topline results from the Phase 2a biomarker study are expected in the third quarter of 2025.

For more information about the Phase 2a study, please visit clinicaltrials.gov and reference identifier NCT06331624.

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 inhibitor of 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.