Redx presents encouraging signal searching data for zelasudil (RXC007) as a well-tolerated treatment for Idiopathic Pulmonary Fibrosis at ERS

• Zelasudil, a potential best-in-class, selective ROCK2 inhibitor shows evidence of anti-fibrotic activity at 12 and 24 weeks in patients with IPF
• Zelasudil reduces FVC decline numerically at 12 weeks and continues to stabilise during open label extension
• Circulating biomarker data supports the anti-fibrotic signal observed
• Combinability with standard of care agents demonstrated, with no treatment related SAEs observed

Alderley Park, UK, 29 September  2025 Redx Pharma, the clinical-stage, biotechnology company focused on developing novel, small molecule, targeted therapeutics for fibrotic disease, today announces the presentation of new data from the zelasudil Phase 2a signal searching study in idiopathic pulmonary fibrosis (IPF) at the European Respiratory Society (ERS) meeting in Amsterdam. The data were presented by Professor Toby Maher, zelasudil Phase 2 Chief Investigator and Professor of Clinical Medicine and Director of the Interstitial Lung Disease Programme at Keck School of Medicine at the University of Southern California.

Professor Toby Maher said: “The data from this study shows zelasudil has the potential to improve lung function in IPF patients with relevant circulating biomarker data that supports the anti-fibrotic activity of the compound.  It is also exciting to see that zelasudil can be easily combined with standard of care anti-fibrotic agents.”

Zelasudil is a potent, oral, small molecule, selective, Rho Associated Coiled-Coil Containing Protein Kinase 2 (ROCK2) inhibitor. The Phase 2a study aimed to assess safety, tolerability, pharmacokinetic and initial efficacy in patients with IPF. Key secondary endpoints included changes in forced vital capacity (FVC), circulating biomarkers such as Pro C3 and pharmacokinetic profiling.

In total, 48 patients participated in the study with baseline demographics and disease characteristics balanced across treatment groups, and in line with historical IPF studies. Patients were randomized in a 3:1 ratio to receive zelasudil or placebo twice daily, for 12 weeks in a double-blind phase at doses of 20mg BID and 50mg BID. In each cohort, patients were split between either no background therapy or on stable doses of pirfenidone or nintedanib.  Upon completing the 12 week double blind treatment period, 35 of the 48 patients enrolled continued into a 12-week open-label extension (OLE) in which placebo patients were able to cross over to zelasudil.

The study demonstrated that zelasudil was well tolerated at both doses with or without background antifibrotic therapy. There were no deaths or treatment related SAEs observed. The most common treatment-related adverse event reported was asymptomatic ALT / AST increases. All events resolved with treatment interruption, and there were no associated bilirubin increases or Hy’s law or potential Hy’s law cases. There was also no evidence of hypotension and no GI related signal in the study.

Zelasudil was shown to numerically reduce FVC decline when compared to placebo at 12 weeks with a 47% reduction in FVC decline (58ml) for patients dosed at 20mg BID and a corresponding 13% reduction in FVC decline (16ml) at 50mg BID. In the OLE, patients who remained on zelasudil continued to benefit from treatment for the entire 24-week treatment period, whilst stabilisation in lung function was also noted in placebo patients who switched to zelasudil. Circulating biomarker data supports the anti-fibrotic signal observed, including CA19-9, CA-125, PRO-C3 and CHI3L1.

Pharmacokinetic data matched predictions from Phase 1 healthy volunteer studies with both doses tested being within the predicted efficacious range. Combinability with standard of care agents was demonstrated, with no clinically relevant drug–drug interactions seen with either nintedanib or pirfenidone.

Dr Helen Timmis, Chief Medical Officer at Redx Pharma added: “IPF is a devastating disease with no new treatments approved in the last decade. This signal searching study is very encouraging in demonstrating the tolerability, combinability and an efficacy signal at this early time point.”

These encouraging data support further investigation of zelasudil as a potential treatment for IPF and other interstitial lung diseases and Redx is seeking a partner to support the next stages of clinical development.

A copy of the abstract presentation deck is available on the Company website at: https://www.redxpharma.com/scientific-publications.

About ROCK2 inhibition and zelasudil

Zelasudil is a potent, oral, small molecule, selective, Rho Associated Coiled-Coil Containing Protein Kinase 2 (ROCK2) inhibitor. Rho-associated coiled-coil forming protein kinase (ROCK) is well established as an anti-fibrotic target and is known to consist of two isoforms ROCK 1 and 2. Pan-ROCK inhibition shows robust anti-fibrotic activity in preclinical models however, systemic pan-ROCK inhibition results in hypotension. This does not happen with selective ROCK2 inhibition, and ROCK2 inhibition alone has been shown  to drive anti-fibrotic efficacy in multiple preclinical fibrosis models including lung, liver, kidney, skin, chronic graft-versus-host disease (cGvHD), and cancer-associated fibrosis.

About Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a debilitating disease of the lungs which progressively causes scarring and a reduction in lung function. Occurring primarily in older adults (>50 years old), it involves irreversible and variable scarring, stiffening, and thickening of the lung tissues, leading to patients experiencing shortness of breath and lack of oxygen absorption. Over 170,000 patients suffer with IPF^[i] and around a further 53,000 people are diagnosed each year (US, 5 EU, Japan). Patients diagnosed with IPF have an estimated life expectancy of 3 to 5 years^[ii]. There is no known cure, and current treatment only slows progression of the disease.

[i] Patient numbers (diagnosed prevalence) & market size forecast data sourced from Global Data (US, EU5, Japan)

[ii] Clinical Estimates from Hyun 2015, Ley 2012, Raghu 2006