The European Commission has granted Orphan Designation to Corbus Pharmaceuticals’ Resunab to treat cystic fibrosis (CF) in the European Union.

In the U.S., Resunab was granted both orphan drug and fast track designation as a potential treatment for CF and systemic sclerosis by the FDA in 2015.

“Receiving Orphan Designation for Resunab in the treatment of CF in the European Union is a noteworthy milestone in our global regulatory strategy for the clinical development of Resunab in CF,” Yuval Cohen, PhD, CEO of Corbus, said in a press release.

Resunab is a first-in-class, synthetic oral endocannabinoid-mimetic drug that binds to the CB2 receptor expressed on activated immune cells and fibroblasts. The activation of the CB2 receptor triggers endogenous pathways that resolve inflammation and stop fibrosis.

Three Phase 2 clinical trials are currently assessing Resunab in cystic fibrosis, systemic sclerosis, and dermatomyositis. Corbus is also planning a fourth study of the drug in systemic lupus erythematosus, which will be funded by the National Institutes of Health (NIH).

The CF trial is a randomized, double-blind, placebo-controlled Phase 2 study (NCT02465450) to assess the safety, tolerability, pharmacokinetics, and effectiveness of Resunab in adults. Subjects were enrolled regardless of their CFTR mutation, infecting pathogens, or baseline treatment.

Enrolled are 89 patients from centers throughout the U.S. and Europe. All patients will be treated with Resunab orally for 84 consecutive days, with an additional 28 days of follow-up. The trial’s efficacy endpoints include lung function as measured by forced expiratory volume in one second (FEV1) and patient-reported symptoms. The trial will also access Resunab’s impact on bacterial load in the lungs and biomarkers of inflammation in sputum and blood.

Data on safety and effectiveness are expected early next year. This trial was partly funded by a $5 million development award from the Cystic Fibrosis Foundation (CFF).

“[Currently] there are no approved treatments for inflammation in CF, which is the major cause of lung damage in individuals with CF,” said Barbara White, MD, chief medical officer of Corbus.

White said that Resunab has so far shown benefit in a murine model of lung inflammation in CF and in other pre-clinical models of lung inflammation and lung fibrosis.

“These data show Resunab’s potential to improve lung inflammation and consequently potentially improve lung function and pulmonary exacerbations in people with CF,” White said.