Treatment with inhaled mannitol is safe and can help to improve lung function in adult patients with cystic fibrosis (CF), a post hoc analysis of data from a concluded Phase 3 trial show.
These results were discussed at the recent 41st European Cystic Fibrosis Society (ECFS) Conference in Belgrade, Serbia, in an oral presentation titled “Phase 3 randomised controlled study of the efficacy and safety of inhaled mannitol in adults with cystic fibrosis.”
Inhaled mannitol is being developed by Pharmaxis and is currently available in some countries (namely in Europe, Russia and Australia) under the brand name Bronchitol. It is still unclear exactly how the treatment works, but it is believed to modulate the underlying defect of CF by improving hydration of the airways, changing mucus properties and easing its clearance.
The treatment safety and efficacy were tested in a Phase 3 trial (NCT02134353), which enrolled 423 adult CF patients (mean age of 27.7) at about 100 sites worldwide and finished in February 2017. Participants were randomized to receive either 400 mg or 50 mg (as a control group) of inhaled mannitol twice a day for 26 weeks.
At the study’s start, patients had a mean percent predicted forced expiratory volume in 1 second of 63.1% (ppFEV1; a measure of lung function).
At its end 26 weeks later, those patients in the experimental treatment arm — given the higher dose of inhaled mannitol — experienced a significant improvement in lung function. They were also found to have improved FEV1 by 54 mL, which corresponds to a 2.24% improvement compared to values at the study’s start.
About 22% of treated patients, and 11.2% of control patients, had an average relative improvement in ppFEV1 of 10% or more, data show.
No significant changes in measures of pulmonary exacerbations were seen between the groups. However, a trend was reported in favor of inhaled mannitol in forced vital capacity, another measure of lung function.
Additional analysis of forced expiratory flow at 25-75% of pulmonary volume (FEF25-75) found that treated patients had a significant change of 0.087 L/s.
As was seen in previous studies, researchers again found that relative change in ppFEV1 after six weeks of treatment was significantly associated with a sustained positive response over the trial’s 26 weeks.
Adverse events were consistent with those reported in other CF studies, and occurred with similar frequency between the two groups, the study said.
Based on the findings, the researchers concluded that inhaled mannitol was shown to be a “safe, effective treatment for adult CF patients that can be used in addition to best standard care.”