Bronchitol: inhaled mucolytic for cystic fibrosis

PHARMACOLOGY

Mannitol is a hyperosmotic agent given by dry powder inhalation. Its exact mechanism of action is unknown, but it may change the viscoelastic properties of mucus in the lungs, increase hydration of the periciliary fluid layer and contribute to increased mucus clearance through mucociliary activity.¹

CLINICAL STUDIES

Two double-blind 26-week phase III studies were performed, in which patients with cystic fibrosis were randomised to receive inhaled mannitol 400mg or control (a sub-therapeutic 50mg dose of inhaled mannitol) twice daily. Participants could receive concomitant recombinant human deoxyribonuclease (rhDNase) and inhaled antibiotics, but hypertonic saline was not permitted.¹

In study CF301, mean FEV₁ improved by 6.5% (118.9ml) in patients receiving mannitol 400mg compared with 2.4% (26ml) in control patients (p<0.001). The treatment effect was significant for both rhDNase users and non-users.²

In study CF302, the relative change in mean FEV₁ was 8.2% (106.5ml) in the treatment group and 4.5% (52.4ml) in the control group (p=0.029).³

The rate of protocol-defined pulmonary exacerbation (presence of specified symptoms and signs plus the use of iv antibiotics) was reduced by 26% with mannitol 400mg in both studies, but this difference did not reach significance.^2,3

References

1. Bronchitol Summary of Product Characteristics, April 2012.
2. Bilton D et al. Eur Respir J 2011; 38: 1071-80.
3. Aitken ML et al. Am J Respir Crit Care Med 2012; 185: 645–52.

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Further information: Pharmaxis