RESUMO
As part of a development programme for a range of new CFC-free beclomethasone dipropionate (BDP) inhalers, two multicentre double-blind studies have been conducted to compare the therapeutic equivalence of a new HFA-134a propellant-formulated BDP metered-dose inhaler (Norton Healthcare Ltd, London, U.K.) with a CFC counterpart for the management of adult patients with all grades of asthma. Doses of 100 micrograms qds for 6 weeks were administered in a low dose study and in a high dose study 500 micrograms qds doses were given for 12 weeks. Efficacy assessments included lung function (FEV1) in the clinic and asthma symptoms, peak flow rates and bronchodilator use by patients on diary cards. Safety parameters measured included routine haematology and biochemistry (including serum cortisols), clinical adverse events and throat swabs for Candida spp. Both CFC and HFA-formulations of inhaled BDP produced similar and significant improvements in lung function and asthma symptoms. In the low dose study, baseline to endpoint FEV1 increased from 2.2 +/- 0.51 to 2.5 +/- 0.81 (P = 0.0001) with BDP-CFC and from 2.2 +/- 0.51 to 2.6 +/- 0.81 with BDP-HFA (P = 0.0001), with no significant difference between treatments. In the high dose study, corresponding increases were 2.1 +/- 0.71 to 2.4 +/- 0.91 (P = 0.0002) for BDP-CFC and 2.1 +/- 0.71 to 2.3 +/- 0.71 (P = 0.017) for BDP-HFA. PEF also improved similarly on both treatments in both studies. Both formulations were well tolerated with no difference in the pattern of adverse events, effect on serum cortisol or Candida colonization. These studies showed that, in the management of asthma, the new HFA-formulated BDP metered dose inhaler is equivalent to, and directly substitutable for, the older CFC-formulated product at the same dose, making change-over for patients straightforward.
