WHO Approves Ensifentrine as Name for Potential Inhaled Treatment Now in Clinical Trials

The World Health Organization (WHO) approved ensifentrine as the recommended name to identify the cystic fibrosis (CF) treatment candidate RPL554.

Verona Pharma’s ensifentrine is an inhaled inhibitor of the enzymes phosphodiesterase 3 and 4, designed to have bronchodilator and anti-inflammatory properties.

The “-fentrine” staple indicates WHO’s recognition that the compound inhibits multiple phosphodiesterases, the company reports.

“We are pleased to receive approval from the WHO for the use of ‘ensifentrine’, which to our knowledge, is the only molecule with an INN assignment using the ‘–fentrine’ stem currently in clinical development,” Jan-Anders Karlsson, PhD, Verona’s CEO, said in a press release.

Karlsson added that this designation underlines “ensifentrine’s position as a novel compound with a dual bronchodilator and anti-inflammatory mechanism of action.”

WHO gives distinctive identifying names to potential treatments to spot their pharmaceutical substances or active ingredients. These designations are officially known as a therapy’s International Non-proprietary Name (INN).

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Gerard Criner, MD, chair and professor of thoracic medicine and surgery at the Lewis Katz School of Medicine at Temple University, said that ensifentrine is the only investigational therapy with such a dual effect that he has come across in his research.

“This could be significant for patients and healthcare providers alike as there have been no new bronchodilator treatment classes over the last four decades,” Criner added.

Ensifentrine is currently being developed not just for CF, but also as a maintenance treatment for chronic obstructive pulmonary disease (COPD), and a potential asthma therapy.

In a Phase 2a trial (NCT02919995), treatment with 1.5 mg or 6 mg of ensifentrine at four-, six-, and eight-hour time points significantly improved lung function in CF patients, as shown by a marked increase in forced expiratory volume in one second.

Preclinical studies also revealed that ensifentrine, either by itself or in combination with other treatments, was able to stimulate different types of CF transmembrane conductance regulator (CFTR) mutants. These altered ion channels result from mutations in the CFTR gene (the cause of CF), and lead to the mucus accumulation in CF patients.

Ensifentrine was also shown to boost the induced increase in CFTR activity by Orkambi (lumacaftor/ivacaftor, by Vertex Pharmaceuticals) in cells expressing specific CFTR mutants.

In Phase 2 trials in COPD patients (NCT02542254 and NCT03028142), ensifentrine improved the bronchodilation action of standard short- and long-acting agents — albuterol or Boehringer Ingelheim’s Atrovent (ipratropium) or Spiriva Respimat (tiotropium) — while also easing lung hyperinflation, seen as a cause of breathlessness in these patients.

Ensifentrine, both as a stand-alone or add-on therapy, also improved lung function in COPD patients, as indicated by a rise in average forced expiratory volume in one second. A European Phase 2b trial (NCT03443414) also showed quality of life improvement in these patients.

“We are very encouraged by the positive data from our studies evaluating ensifentrine in COPD and CF, and look forward to advancing this novel drug candidate into late-stage development as a potential new treatment for patients,” Karlsson concluded.