GRI Bio's GRI-0621 Shows Promise in Phase 2a IPF Trial with Disease-Modifying Potential

GRI BioSearch company has reported positive topline results from its Phase 2a clinical trial evaluating GRI-0621Search drug for idiopathic pulmonary fibrosisSearch disease (IPFSearch disease), demonstrating both safety and early signals of disease-modifying activity that could differentiate it from existing treatments. The study met its primary and secondary endpoints, showing the oral therapy was well tolerated over 12 weeks while displaying improvements in biomarkers associated with fibrosis resolution.

Safety Profile Differentiates from Current IPF Treatments

The Phase 2a study enrolled 35 subjects with IPFSearch disease who were randomized 2:1 to receive GRI-0621Search drug 4.5mg or placebo once daily for 12 weeks. The trial met its primary endpoint, with no safety or tolerability concerns observed and no drug-related severe or serious adverse events reported. The most common adverse events were dry skin, dry lips, and muscle and joint pain.

Notably, GRI-0621Search drug showed a differentiated safety profile compared to existing IPFSearch disease treatments. There were no increases in cough (0% in the GRI-0621 arm versus 25% in placebo) or gastrointestinal disorders (diarrhea reported in 13% versus 33% for placebo). This is particularly significant given that 80% of enrolled subjects were taking background pirfenidoneSearch drug or nintedanibSearch drug, the current standard-of-care treatments for IPF.

"Treatment of patients with IPFSearch disease in the GRI-0621Search drug Phase 2a trial was observed to be safe and well tolerated through the completion of the 12-week study," said Toby Maher, MD, PhD, Professor of Clinical Medicine at Keck School of Medicine, USC Los Angeles.

Biomarker Evidence Suggests Disease-Modifying Activity

The study's secondary endpoints provided compelling evidence of GRI-0621Search drug's potential disease-modifying effects through improvements in serum biomarkers of collagen turnover. The drug demonstrated a shift from fibrogenic to fibrolytic collagen remodeling patterns, suggesting active resolution of fibrosis rather than merely slowing disease progression.

PRO-C6, a biomarker of type VI collagenSearch term synthesis, decreased by 3% from baseline in GRI-0621Search drug-treated subjects while increasing 12% in placebo subjects. Conversely, C6M, a biomarker of type VI collagen degradation, increased 6% in treated subjects and decreased 3% in placebo subjects. The type VI collagen remodeling rate shifted from fibrogenic (+10%) in placebo-treated subjects to fibrolytic (-7%) in those receiving GRI-0621.

Alveolar Basement Membrane Repair Mechanism

Beyond fibrosis resolution, GRI-0621Search drug appeared to induce repair of the alveolar basement membrane, a hallmark feature destroyed in IPFSearch disease. PRO-C4, a biomarker of type IV collagenSearch term synthesis crucial for basement membrane repair, increased 9% from baseline in GRI-0621-treated subjects while decreasing 2% in placebo subjects.

The type IV collagenSearch term remodeling rate shifted from fibrolytic (-16%, indicating continued basement membrane destruction) in placebo subjects to neutral (0%) in GRI-0621Search drug-treated subjects, suggesting activation of lung tissue repair mechanisms.

Gene expression data supported this repair mechanism, with GRI-0621Search drug significantly reducing DLK1Search term (-6.46 LogFC; FDR 0.0003), a gene involved in lung epithelial cell regeneration and alveolar basement membrane repair. The drug also reduced neutrophil and macrophage activity and downregulated genes associated with fibrosis and disease progression.

Functional Improvements in Lung Capacity

Exploratory endpoints demonstrated functional improvements in forced vital capacity (FVC), a key measure of lung function in IPFSearch disease. Placebo-adjusted changes from baseline showed FVC increased by 99 ml in the GRI-0621Search drug-treated arm and 139 ml in the subset taking both GRI-0621 and standard of care.

Importantly, 39% of GRI-0621Search drug-treated subjects experienced an increase in FVC at 12 weeks compared to 80% of placebo subjects who experienced a decline. This represents a meaningful difference in disease trajectory for treated patients.

Targeting NKT Cells for Disease Modification

GRI-0621Search drug is an RARβγSearch term agonist designed to target Natural Killer T (NKT) cells, which are key regulators in the inflammatory cascade. The drug specifically inhibits type I invariant NKT (iNKT) cell activity, which plays a critical role in propagating injury, inflammatory response, and fibrosis in IPFSearch disease.

"The positive Phase 2a results represent an important milestone for our IPFSearch disease program and a compelling early signal of GRI-0621Search drug's disease-modifying potential," commented Marc Hertz, PhD, Chief Executive Officer of GRI BioSearch company. "These results reinforce our belief in GRI-0621's differentiated mechanism and support its potential to go beyond slowing disease progression by directly impacting core drivers of IPF."

The company's approach represents a potential paradigm shift in IPFSearch disease treatment, moving beyond current therapies that primarily slow disease progression to one that may actively reverse fibrotic processes and promote lung repair. With over 1,700 subjects previously treated with the drug's underlying chemistry for up to 52 weeks, GRI BioSearch company has established a substantial safety database supporting further development.