Bronchitol, Inhaled Powder for CF Mucus Clearance, Arrives in US

Bronchitol (mannitol), an inhaled mucus-clearing treatment for cystic fibrosis (CF), is now commercially available in the U.S., according to Chiesi USA, which is marketing the therapy in the country.

“We are excited to bring the first dry powder inhaled mucoactive agent to the U.S. for adults with CF, delivered by a portable device that doesn’t require routine maintenance or cleaning,” Jon Zwinski, Chiesi’s general manager and CEO, said in a press release.

Bronchitol, developed by Pharmaxis, was approved as a maintenance treatment for adults with clinically stable disease by the U.S. Food and Drug Administration (FDA) in November. The FDA based its decision on findings from three Phase 3 trials (NCT00630812, NCT00446680, and NCT02134353), which broadly showed that Bronchitol improved lung function in people with CF.

Full results from one of the trials (NCT02134353) were recently published in the Journal of Cystic Fibrosis, in the study “Efficacy and safety of inhaled dry-powder mannitol in adults with cystic fibrosis: An international, randomized controlled study,” led by a team of researchers from Chiesi and Pharmaxis, as well as those at academic institutions.

Conducted at 101 sites across 21 countries, this trial enrolled 423 adults with CF, of whom 373 (88.2%) completed the study. Their mean age was 27.7, slightly over half were male (53%), and 97.2% were Caucasian.

Participants were randomized to treatment with either 400 mg Bronchitol (active treatment) or 50 mg Bronchitol (control group), both given twice daily via a dry-powder inhaler for 26 weeks.

The study’s main measure of efficacy was forced expiratory volume (FEV1), which assesses how much air a person can forcibly exhale in one second, and is a common test of lung function. After 26 weeks of treatment, patients in the active treatment group had an average increase of 1.6% in FEV1, significantly greater than the 0.39% increase seen in the control group.

Statistical analyses also confirmed that the active treatment outperformed control in terms of FEV1 over the study’s length, as well as at six and 14 weeks of treatment. Other measures of lung health also favored Bronchitol at 400 mg twice daily over 50 mg twice a day.

Adverse events were reported in about two-thirds of patients in both treatment groups. Most were mild or moderate in severity and not considered related to Bronchitol treatment. Among the most common were cough, hemoptysis (coughing up blood), throat pain, vomiting, fever, and joint pain.

Safety data were generally consistent with that of other clinical trials of Bronchitol. Of note, hemoptysis was reported in about 10% of participants in both these treatment groups, with one person in the active group having a serious and treatment-related hemoptysis event. Based on prior data, researchers expected a rate of hemoptysis closer to 20%, and considered the rate in this trial “reassuring.”

Bronchitol has “a good overall safety and tolerability profile,” they wrote.

“This safety profile, together with the effect on FEV1 make mannitol [Bronchitol] a suitable therapeutic option in combination with other CF treatments — especially given it is administered via an easy-to-use dry-powder inhaler,” the team concluded.

Although Bronchitol’s precise mechanism of action is not known, the treatment is believed to work by drawing water into the airways, which makes the sticky mucus that is typical in CF thinner and easier to cough up. Better mucus clearance is thought to improve lung function.

Before treatment initiation, patients are required to undergo a Bronchitol tolerance test. Here, healthcare providers give a first dose to a person to evaluate if the treatment cause a bronchospasm (a sudden tightening in the walls of the airways) or a decrease in FEV1 and in oxygen blood levels. If any of these events occur, Bronchitol will not be prescribed.