EASD: Inhaled Insulin Breathes New Life into Therapy for Diabetes

AMSTERDAM, Sept. 18 -- Inhaled insulin can't entirely replace injections, but it might help patients with type 1 or type 2 diabetes get better control of their glucose levels, said diabetologists here.

Many patients whose type 2 diabetes is poorly controlled with oral medications are reluctant to start multiple daily injections, and some patients with type 1 diabetes may skip one or more daily doses, and for these patients inhaled insulin may be a good therapeutic option, said Anthony Barnett, M.D., of the University of Birmingham, England, at an industry-supported symposium held in conjunction with the European Association for the Study of Diabetes meeting.

Inhaled insulin is rapidly absorbed into the circulation by the highly vascularized tissues in the lung, which makes it ideal for mealtime dosing. In addition, intra-patient variability seems to be comparable to that of the subcutaneous insulins, said Dr. Barnett.

Most of the experience with inhaled insulin has been in type 1 diabetes, where, in trials lasting up to three years, it has demonstrated comparable efficacy to subcutaneous insulin for maintaining glycemic control. This was true even when inhaled insulin was used as part of an intensive insulin regimen, he said.

More recently, inhaled insulin has shown promise both as monotherapy and in combination with oral antidiabetic agents for improving glycemic control in patients inadequately controlled on oral agents alone.

"In insulin-experienced patients with type 2 diabetes, several studies have demonstrated a comparable decline form baseline HbA1c of up to three-years duration with inhaled human insulin when compared with a subcutaneous insulin regimen -- regular insulin, insulin lispro, or insulin aspart," Dr. Barnett said.

A slight decline in pulmonary function, as measured by forced expiratory volume in 1 second (FEV₁) has been documented with inhaled insulin, he said, but the effect was, "small, clinically insignificant, and did not progress over two years of continuous therapy." Moreover, the decline in lung function is reversible, he said.

If inhaled insulin can induce patients with type 2 diabetes to be more compliant with therapy, it could help prevent complications later on, said Lawrence Blonde, M.D., of the Ochsner Clinic Foundation in New Orleans.

Dr. Blonde cited a study, currently in press, indicating that, for whatever reason -- fear of needles, denial, inconvenience, technique -- 25% of patients with type 2 diabetes delay starting recommended insulin therapy for nearly two years, and 50% delayed "for almost five years after failure of glycemic control with oral antidiabetic polytherapy, even in the presence of diabetes-related complications," he said.

Survey data also suggest that the availability of an alternative to subcutaneous insulin would significantly improve the likelihood of compliance among patients with type 2 diabetes poorly controlled on oral agents alone, he added.

The efficacy of inhaled insulin for mealtime control of glycemia also points out the need to consider adding post-prandial glucose and glycemic variabilty to the old standbys of fasting plasma glucose and glycosylated hemoglobin (HbA1c) said Louis Monnier, M.D., of Montpellier University in Montpellier, France.

Post-prandial glucose "is at the crossroads of the two main glycemic disorders that contribute to diabetes complications: acute and sustained chronic glucose fluctuations," he said.

The availability of alternatives to subcutaneous insulin coincides with a more aggressive approach to the treatment of diabetes in Europe, commented Jacques Philippe, M.D., of the University of Geneva Medical School in Geneva, Switzerland.

But given the reality of the worldwide diabetes epidemic, the challenge for physicians and patients will be to meet new and more ambitious targets for control of glycemia.