The data on Exubera (inhaled insulin) was found effective and well tolerated in controlling blood glucose levels over a two-year period in patients with Type 2 diabetes. The results were presented at the Annual Meeting of the European Association for the Study of Diabetes in Munich, Germany.

Exubera, an inhaled insulin, is being developed for use in patients with type 1 and type 2 diabetes through a collaboration between Pfizer Inc and Aventis.

According to release from Pfizer, these combined results are from two six-month clinical studies in patients with type 2 diabetes that were designed to assess the efficacy of Exubera when added to either sulfonylurea or metformin as compared to the combination of these oral agents without Exubera. Following the initial six-month trials, patients continued into extensions of up to an additional 18 months, where the primary objective was to assess long-term pulmonary safety. A total of 304 patients completed the two-year period.

During the two-year period, patients in both the Exubera and the control treatment groups experienced declines in pulmonary function from baseline measured as FEV 1 (forced expiratory volume in one second) and DL CO (carbon monoxide diffusing capacity). At week 24, small differences in declines in FEV1 and DLCO in favour of oral agents were observed (FEV1 -0.063 L/second; DLCO -0.275 mL/min/mm Hg). After two years of treatment, though, confidence intervals for changes in FEV1 and DlCO indicated no significant differences between treatment groups. Specifically, the two-year difference in FEV 1 between the two treatment groups was -0.039 L/second favouring the oral agent group and the difference in DL CO was +0.112 mL/min/mm Hg favouring the Exubera-treated group.

In addition, study results showed that HbA1c, an indirect way to measure blood glucose levels over time, decreased from 9.6 per cent to 7.7 per cent after two years for patients receiving Exubera and to 8.1 per cent for patients in the control group. Additional anti-diabetic agents including subcutaneous insulin were allowed in both groups in the final 18 months of the study to achieve glycemic control. The most common adverse event in the Exubera-treated group was cough, which was considered to be transient and mild.

"These data show that small pulmonary function differences between the two groups occurred early after treatment initiation, had no identified clinical relevance, and did not progress with two years of continued inhaled insulin treatment," said professor Manfred Dreyer, lead study investigator, Bethanien Krankenhaus, Hamburg, Germany.

Exubera has been studied in more than 3,000 patients, some for up to six years. In February 2004, Pfizer and Aventis submitted Exubera for review by the European Medicines Agency for marketing approval in the European Union. Interactions with the European regulatory authorities are ongoing, the release added.