LONDON (Reuters Health) – Diabetics with asthma absorb less insulin than nonasthmatic diabetics when the drug is inhaled rather than injected, new research presented here Monday shows. The findings, presented at the annual meeting of the European Association for the Study of Diabetes, could have important implications for inhaled insulin products currently under development.
Lead researcher Dr. R. Henry of San Diego, California told delegates to the meeting: 'Asthma can potentially affect the pharmacokinetics of inhaled insulin. The asthmatic group had a significantly lower share of insulin concentration, indicating that they absorb significantly less than normal subjects. One possible explanation is their impaired pulmonary function.'
More encouragingly, the same study showed that inhaled insulin is safe for use by asthmatics, with no effect on lung capacity or airway reactivity.
This is believed to be the first study to examine whether inhaling the drug is a viable alternative for people with concomitant respiratory disease. US researchers studied a group of diabetic volunteers using the AERx insulin diabetes management system. Developed by California-based firm Aradigm Corporation, AERx is an experimental treatment that delivers a liquid aerosol of insulin deep into the lungs.
The subjects, 28 healthy volunteers and 16 asthmatic volunteers, were given two different doses of the inhaled drug, the first equivalent to six subcutaneous units of insulin, the second equivalent to 17 units. The researchers then measured insulin uptake and used a range of lung function tests to monitor the drug's effect on the airways.
They found that insulin uptake in the asthmatic group was significantly lower than in the nonasthmatic controls (p = 0.013). However, no significant change in forced expiratory volume in 1 second, forced vital capacity, or FEV1/FVC was noted from pre- to post-dose.