GRI Bio Releases 6-Week Biomarker Results From Ongoing Phase 2a Trial Evaluating Treatment In Idiopathic Pulmonary Fibrosis (IPF)

GRI Bio, Inc., a biotechnology company developing Natural Killer T (NKT) cell modulators for treating inflammatory, fibrotic, and autoimmune diseases, has released interim six-week biomarker findings from its ongoing Phase 2a clinical trial evaluating GRI-0621 for Idiopathic Pulmonary Fibrosis (IPF). The second interim analysis involved biomarker data from the first 24 participants. Patients treated with GRI-0621 showed a reduction in fibrogenesis markers (such as PRO-C3 and PRO-C6) and a favorable fibrolytic profile based on the ratios of collagen formation to degradation (e.g., PRO-C3/CTX-III, PRO-C4/C4Ma3, and PRO-C6/C6M). 

Additionally, GRI-0621-treated patients demonstrated increased basement membrane remodeling markers (C1M, C3M, C4Ma3, C6M), suggesting the induction of tissue repair mechanisms compared to those receiving placebo. Following the interim review, the Independent Data Monitoring Committee (IDMC) found no safety concerns and recommended that the study continue without changes. More patient data will be required to determine whether GRI-0621’s effects on biomarkers translate into measurable improvements in lung function.

This Phase 2a study is a randomized, double-blind, placebo-controlled, two-arm trial involving approximately 35 IPF patients assigned in a 2:1 ratio to receive either 4.5mg of GRI-0621 or placebo, taken orally once daily for 12 weeks. The trial’s primary objective is to assess the safety and tolerability of GRI-0621 through clinical labs, vital signs, and adverse event tracking. Secondary endpoints include changes in serum biomarkers at weeks 6 and 12, pharmacokinetics at week 12, and pharmacodynamic activity measured by NKT cell inhibition in blood and bronchoalveolar lavage (BAL) fluid.

Marc Hertz, PhD, Chief Executive Officer of GRI Bio, said in a statement, “These 6-week interim biomarker data, while early and based on a small subset of participants, continue to be encouraging. Although the study remains blinded and we do not yet have visibility into individual patient data, background anti-fibrotic use or demographic distribution, we are seeing promising directional signals with GRI-0621, including reduced fibrogenesis, increased fibrolysis and improvement in the remodeling rate, or net changes in ECM formation versus resolution.”

He also added, “These findings remain consistent with the results seen at the 2-week interim analysis and provide further insight into the full potential of GRI-0621. Our team remains focused on the successful execution of the study and look forward to reporting topline data later this year, and hope to be able to report findings regarding pulmonary function in the coming weeks.”

An additional sub-study will evaluate the number and activity of NKT cells in BAL fluid in up to 12 eligible patients. Exploratory outcomes include assessing pulmonary function, gene expression, and cell profiling at multiple time points. Previous interim safety reviews at both the two-week and six-week marks indicated GRI-0621 was safe and well tolerated. Earlier analyses also suggested potential anti-fibrotic activity based on changes in key biomarkers like PRO-C3. 

The drug’s receptor selectivity and safety profile remain consistent with previous findings from earlier clinical studies involving oral tazarotene in over 1,700 patients. Topline results from the full 12-week biomarker study are expected in the third quarter of 2025. Additional pulmonary function data, flow cytometry, and gene expression findings are anticipated in the coming weeks and months.