EI‑1071, a colony-stimulating factor‑1 receptor (CSF‑1R) inhibitor and potential treatment for idiopathic pulmonary fibrosis (IPF), has been granted Orphan Drug Designation by the US Food and Drug Administration (FDA). This will speed the development of the drug candidate for this rare disease.

“Idiopathic pulmonary fibrosis has a devastating impact on patients’ lives and more effective therapies are urgently needed, and the Orphan Drug Designation validates the potential of EI‑1071 to offer a new therapeutic option for patients living with this disease,” said Hung-Kai Kevin Chen, chief executive officer of Elixiron, the developers of the treatment, in a press release.

“Building on promising data from preclinical and phase 1 studies, we are actively evaluating options to accelerate the development of EI‑1071 to address unmet medical needs.”

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EI‑1071 is a small molecule that inhibits the tyrosine kinase activity of CSF‑1R. It has already been tested in phase 1 clinical trials. In preclinical models, EI‑1071 showed promising therapeutic effects; it reduced lung fibrosis and improved respiratory functions.

Read more about the treatment of IPF.

IPF, a chronic and progressive disease, is characterized by lung fibrosis and loss of function. CSF‑1 signaling is important for the regulation of pulmonary macrophages and causes inflammatory damage and fibrosis in IPF. There is currently no known cure for the disease and the only 2 FDA-approved drugs, pirfenidone and nintedanib, cannot halt the progression of the disease. Life expectancy is only around 3 to 5 years following diagnosis.

Orphan Drug Designation is given to drug candidates being developed for rare diseases affecting fewer than 200,000 people in the US. It provides incentives such as tax credits for eligible clinical trials, waiver of application fees, and market exclusivity for 7 years following approval by the FDA.


Elixiron Immunotherapeutics announces orphan drug designation granted to CSF-1R inhibitor, EI-1071 for the treatment of idiopathic pulmonary fibrosis. News release. Elixiron Immunotherapeutics; August 2, 2022.