GRI Bio Finalizes Patient Enrollment For Phase 2a Trial Of GRI-0621 Targeting Idiopathic Pulmonary Fibrosis (IPF)

GRI Bio, Inc., a biotechnology company focused on developing Natural Killer T (NKT) cell modulators to treat inflammatory, fibrotic, and autoimmune diseases, has completed patient enrollment in its Phase 2a clinical trial of GRI-0621 for the treatment of Idiopathic Pulmonary Fibrosis (IPF). The study is a key step in evaluating the safety, tolerability, and biological effects of the drug in humans.

The randomized, double-blind, placebo-controlled Phase 2a study enrolled approximately 35 patients with IPF across multiple centers. Participants were assigned in a 2:1 ratio to receive either a once-daily 4.5mg oral dose of GRI-0621 or a placebo for 12 weeks. Alongside the main study, a sub-study is being conducted to assess NKT cell count and activity in bronchoalveolar lavage (BAL) fluid from up to 12 eligible participants.

The primary objective of the study is to evaluate the safety and tolerability of GRI-0621 based on clinical labs, vital signs, and any reported side effects over the 12-week treatment period. Secondary objectives include tracking changes in serum biomarkers at weeks 6 and 12, assessing the drug’s pharmacokinetics at week 12, and evaluating its pharmacodynamic activity by measuring the inhibition of iNKT cell activation in both blood and BAL fluid.

Exploratory endpoints aim to investigate GRI-0621’s potential effects on lung function, as well as deeper molecular analyses such as flow cytometry and gene expression profiling at various time points. Previous interim safety analyses from the same study showed positive results. After 2 and 6 weeks of treatment, GRI-0621 was reported to be safe and well-tolerated in the first 12 and 24 patients, respectively. No significant changes were observed in lipid levels, including LDL, HDL, or triglycerides. These findings supported the continuation of the trial, as confirmed by recommendations from the interim analysis committee.

Marc Hertz, PhD, Chief Executive Officer of GRI Bio, mentioned, “We are pleased to complete enrollment of this important trial and take another step toward potentially providing a much needed treatment option for patients with IPF. Looking ahead, we remain on track to report 6-week interim biomarker results in July 2025, followed by topline data expected in the third quarter of this year. Our team is diligently working to bring this trial across the finish line and we look forward to providing updates in the near future.”

In addition to safety, early biomarker data from the first 12 patients indicated a potential anti-fibrotic effect, as seen in reduced levels of PRO-C3 in patients treated with GRI-0621 compared to those on placebo. The independent data monitoring committee (IDMC) found no safety concerns and recommended that the study continue as planned. GRI Bio expects to release additional interim biomarker results from the 6-week analysis in July 2025, with full topline data from the study anticipated in the third quarter of 2025. These results will provide important insights into the therapeutic potential of GRI-0621 for patients with IPF.