Zelasudil (RXC007, ROCK2 selective) - Redx (2024)

Next-generation selective ROCK2 inhibitor for the treatment of interstitial lung diseases and other fibrotic indications with an initial Phase 2 clinical programme underway in idiopathic pulmonary fibrosis

Phase 2a clinical study commenced Q4 2022, topline data expected 2024

Zelasudil is a potent, highly selective and orally-active inhibitor that targets Rho-Associated Coiled-Coil Containing Protein Kinase 2 (ROCK2) which sits at a nodal point in cell signalling pathways, central to fibrosis. The role of ROCK2 in a diverse range of cellular processes allows zelasudil to have pleiotropic effects, affecting multiple cell signalling pathways associated with fibrosis. Selective inhibition of ROCK2 has the potential to prevent the hypotensive side effects typically associated with systemic pan-ROCK inhibitors (where both ROCK1 and ROCK2 are inhibited).

Our ROCK2 inhibitor, zelasudil, has demonstrated potential preclinically to be an attractive agent for the treatment of fibrotic indications. Additionally, zelasudil has shown preclinical proof-of-concept in immune-mediated models, which supports the development of zelasudil into other interstitial lung diseases beyond IPF, and in other fibrotic indications such as cancer-associated fibrosis.

Zelasudil Development Overview

ROCK2 signalling plays a key role in both the inflammatory component and the tissue remodelling that drives disease progression in many fibrotic conditions. Our approach was to apply our medicinal chemistry expertise to produce a next-generation ROCK2 inhibitor with optimised characteristics including selectivity to improve safety profile and side effects, reduce drug-drug interaction liabilities and to have improved physicochemical properties to achieve increased exposures at lower doses.

The orphan disease idiopathic pulmonary fibrosis (IPF), a severe and life-threatening chronic lung condition is being targeted as the first indication for clinical development. With a very poor prognosis, similar to many cancers, and limited treatment options, IPF affects over 170,000 patients in the US, EU5 and Japan alone. Zelasudil is currently in a Phase 2 clinical programme for IPF and has also shown promising outcomes in a number of preclinical models for other interstitial lung diseases as well as cancer-associated fibrosis.

Zelasudil has been shown to be well tolerated in a Phase 1 clinical study in healthy volunteers and is now being investigated in a Phase 2 clinical programme in patients with IPF.

Zelasudil Highlights to date

In Phase 1 study in healthy volunteers:

• Zelasudil confirms good safety and pharmaco*kinetic profile
• Well tolerated with few treatment emergent adverse events reported
• No evidence of hypotension validating rationale for selective ROCK2 inhibition
• Mean half-life of 9-11 hours potentially suitable for once or twice daily dosing.

Preclinical studies:

Zelasudil activity in patient tissue as well as in both chemically induced and immune-mediated preclinical models supports the core development plan in IPF and other interstitial lung diseases. Zelasudil was seen to be efficacious in several in vivo preclinical models of fibrosis, including:

• Therapeutic Murine Bleomycin-induced IPF Model
• Therapeutic Murine Sclerodermatous chronic Graft versus Host (immune mediated ILD) mode
• Carbon tetrachloride (CCl₄)-induced liver fibrosis model
• Human fibrotic lung tissue isolated from resected lung.

Additionally, zelasudil has shown promising results in Therapeutic Murine Pancreatic Cancer Patient Derived Xenograft models, supporting a development plan in cancer-associated fibrosis.

Zelasudil is a next generation ROCK2 selective inhibitor with potential to improve safety and therapeutic outcomes

Our approach in the ROCK2 project was to apply our medicinal chemistry expertise to produce a next generation ROCK2 inhibitor with improved characteristics including improved selectivity to improve safety and side effects, to have lower cytochrome P450 actions to reduce drug-drug interaction liabilities and to have improved physicochemical properties to achieve increased exposures at lower doses.

ROCK2 is an intracellular kinase with multiple cellular functions. ROCK2 sits at a nodal point in a cell signalling pathway, believed to be central to fibrosis

ROCK2 signalling plays a key role in both the inflammatory component and the tissue remodelling that drives disease progression in many fibrotic conditions. ROCK2 expression and activity have been shown to be upregulated in acute inflammatory injury and in chronic diseases such as diabetes, metabolic syndrome and IPF. Selective inhibition of ROCK2 has the potential to prevent the hypotensive side effects typically associated with systemic pan-ROCK inhibitors (where both ROCK1 and ROCK2 are inhibited).

Zelasudil Activity on Patient Tissue and in Preclinical Models Supports CoreDevelopment Plan in IPF and CF-ILDs

Zelasudil has a strong preclinical package in lung fibrosis which underpins our approach in the clinic. It has shown good anti-fibrotic effects in both immune mediated and chemically induced models of lung fibrosis as is shown in the top 2 graphs, where there is strong inhibition of collagen deposition in the lung. In the bottom panel there is strong modulation of key fibrosis genes in human diseased tissue derived from lung fibrosis patients who have undergone transplant therapy.

Phase 1 data in healthy volunteers confirms good safety and pharmaco*kinetic profile

The zelasudil Phase 1 trial in health volunteers show the overall pharmaco*kinetic profile to be as predicted from the preclinical data and the plasma concentration increases have been essentially linear, showing a drug-like pharmaco*kinetic profile.

Evidence in pancreatic models demonstrates potential of ROCK2 inhibition in cancer associated fibrosis

Data from a pancreatic ductal adenocarcinoma (PDAC) model showed that zelasudil in combination with gemcitabine/Abraxane® in a metastatic and high-extra cellular matrix (ECM) patient-derived PDAC model, increased survival compared to single agent standard of care alone. Furthermore, data from a chemotherapy-resistant patient derived model in which collagen content is increased upon development of resistance showed that a close analogue of zelasudil, REDX10616, in combination with FOLFIRINOX re-sensitised the tumour to treatment and led to a striking increase in survival. In addition, in the gold standard KPC syngeneic pancreatic cancer mouse model zelasudil also increases survival in combination with anti-PD1 in this normally PD1 resistant model.

Phase 2a dose ranging study in IPF with data readout expected 2024

Phase 2a dose ranging study to provide early efficacy readouts, safety and tolerability in IPF patients with or without background antifibrotic IPF therapy. The dosing duration of the main study is 12 weeks and although the study primarily provides safety and pharmaco*kinetic data, there will also be early readouts on FVC and other efficacy endpoints.

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