Efficacy response of inhaled beclomethasone dipropionate in asthma is proportional to dose and is improved by formulation with a new propellant

Background: This study tested the hypothesis that there mould be improved a sthma control with increasing doses of beclomethasone dipropionate (BDP) fo rmulated in hydrofluoroalkane-134a (HFA-BDP) and the standard chlorofluoroc arbon propellants (CFC-BDP), Because HFA-BDP has improved lung deposition c ompared with CFC-BDP, this study also tested the hypothesis that HFA-BDP wo uld provide more effective control of asthma than CFC-BDP, Methods: In this multicenter, randomized, parallel-group blinded study, ast hmatic subjects who had deterioration in asthma control after discontinuati on of inhaled corticosteroids were randomized to receive one of 6 possible treatments: 100 mu g/d, 400 mu g/d, or 800 mu g/d of HFA-BDP or 100 mu g/d, 400 mu g/d, or 800 mu g/d of CFC-BDP for 6 weeks. Changes in spirometry, d aytime asthma symptom and nighttime asthma-related sleep disturbance scores , morning and evening peak expiratory flows, and daily use of inhaled beta- agonist for symptom control on diary cards were assessed over 6 weeks of tr eatment. Results: Three hundred twenty-three patients mere randomized to the 6 treat ment groups, which had similar demographics and baseline lung function, The re were significantly larger changes from baseline at week 6 in FEV1 percen t predicted with increasing doses of both HFA-BDP and CFC-BDP, The FEV1 per cent predicted dose-response curve for HFA-BDP was shifted to the left comp ared with the dose-response curve for CFC-BDP, By using the Finney bioassay method, it was calculated that 2.6 times as much CFC-BDP would be required to achieve the same improvement in FEV1 percent predicted as HFA-BDP (95% confidence interval, 1.1-11.6), All treatment groups except the 100 mu g/d CFC-BDP group tolerated study drug well, Ten (17%) of 59 patients in this g roup reported an acute asthma episode, increased asthma symptoms (6 of the 8 reports of increased asthma symptoms were classified as severe), or both, and 8 patients withdrew from the study (3 for adverse events related to as thma), Conclusions: Increasing doses of inhaled corticosteroids lead to improved l ung function and asthma control. Moreover, the reformulation of BDP in HFA enables effective asthma control at much lower doses than CFC-BDP.