Zelasudil granted FDA orphan drug status as IPF treatment candidate

Novel oral therapy seen to lessen scarring in preclinical studies

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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Zelasudil, an experimental treatment for idiopathic pulmonary fibrosis (IPF) that’s now being tested in clinical trials, has been granted orphan drug status by the U.S. Food and Drug Administration (FDA).

The FDA awards this designation to therapies with the potential to substantially improve care for people with rare diseases, defined as conditions that affect fewer than 200,000 people in the U.S. The designation is intended to advance the development of treatments for rare disorders, and provides certain incentives to drug manufacturers — including a guarantee of seven years of market exclusivity if the therapy ultimately is approved.

“We are delighted that the FDA has recognised the potential of zelasudil for the treatment of IPF and granted orphan drug designation,” Jane Robertson, MD, chief medical officer at Redx Pharma, zelasudil’s developer, said in a company press release.

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Zelasudil now being tested in IPF patients in Phase 2a trial

Previously known as RXC007, zelasudil is an oral treatment that’s designed to block the activity of Rho-associated protein kinase 2 (ROCK2), a protein that plays a central role in certain molecular pathways that are thought to drive scarring (fibrosis) in IPF and other fibrotic disorders.

In preclinical models, zelasudil showed the ability to lessen scarring — and it was generally well tolerated in a Phase 1 study of healthy volunteers.

“Selectively targeting ROCK2 is an exciting, novel approach which could provide a new treatment option for patients with IPF, and with potential applications in other interstitial lung diseases and cancer-associated fibrosis,” Robertson said.

Redx now is sponsoring a Phase 2a clinical trial (NCT05570058) to test zelasudil in adults, ages 40 to 80, diagnosed with IPF within five years of entering the study. The trial is recruiting participants at a handful of sites in Europe; additional sites in Europe and the U.S. are expected to open in the future.

We are encouraged by both the strength of our preclinical package as well as the clinical results to date and we look forward to reporting Phase 2a topline data in Q1 2024.


An estimated 64 trial participants will be randomly assigned to take zelasudil or a placebo, for about three months. A few different dosing regimes are being tested, with total daily doses ranging from 20 to 70 mg. The therapy is taken either once or twice daily.

The main goal of the study is to assess the safety profile of zelasudil in people with IPF. The therapy’s pharmacological activity and effects on lung function also will be evaluated. Topline data are expected early next year.

“We are encouraged by both the strength of our preclinical package as well as the clinical results to date and we look forward to reporting Phase 2a topline data in Q1 2024,” Robertson said.

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