Waiting to inhale: noninjectable insulin, are we there yet?

Randomized study to characterize glycemic control and short-term pulmonary function in patients with type 1 diabetes receiving inhaled human insulin (exubera)

OBJECTIVE

Previous studies with inhaled human insulin [Exubera (EXU); insulin human (recombinant DNA origin) Inhalation Powder, Pfizer Inc., New York, NY; Nektar Therapeutics, San Carlos, CA) show comparable efficacy to sc insulin and small declines in pulmonary function in type 1 and 2 diabetes. This is a detailed characterization of short-term efficacy and pulmonary safety profile of EXU.

RESEARCH DESIGN AND METHODS

In a 24-wk multicenter study, 226 nonsmoking patients with type 1 diabetes and normal lung function were randomized to intensive regimens of premeal EXU or sc insulin for 12 wk (comparative phase), followed by sc insulin for 12 wk (washout phase). Glycosylated hemoglobin, hypoglycemia, general adverse events, and pulmonary function were measured. Forced expiratory volume in 1 sec and carbon monoxide diffusion capacity were measured using standardized equipment and methodology.

RESULTS

Comparable declines from baseline in glycosylated hemoglobin were observed in both groups (0.5%) and sustained throughout the study. There was a higher rate of hypoglycemia (risk ratio 1.23; 90% confidence interval 1.16, 1.30) but a lower rate of severe hypoglycemia (risk ratio 0.51; 90% confidence interval 0.30, 0.86) with EXU vs. sc insulin. The treatment group differences in changes from baseline in forced expiratory volume in 1 sec and carbon monoxide diffusion capacity were small, occurred within 2 wk of EXU initiation, and were reversible shortly after discontinuation. More patients reported mild cough with EXU vs. sc insulin (30.9% vs. 7.8%, respectively).

CONCLUSIONS

Three months of EXU therapy is as effective and well tolerated as intensive sc insulin therapy. This study supports the role of EXU in type 1 diabetes.

Inhaled insulin delivery--where are we now?

Since 1925, when the concept of treating diabetes with inhaled insulin (INH) was originally published, a number of clinical challenges have been resolved through technological advancements. Efforts by pharmaceutical partnerships or individual companies have resulted in the development of both injection-free devices and novel insulin formulations. Four different INH systems are now in phase 3 of clinical development, and several other INH systems are in earlier stages of clinical study. Clinical data consistently demonstrate that INH therapy is comparable to subcutaneous (SC) therapy in improving glycaemic control in patients with either type 1 or type 2 diabetes, generally without greater risk of overall hypoglycaemia. INH is generally well tolerated and appears to be safe. Adverse-event profiles for INH therapies are similar to SC insulin therapy, with the majority of events being reported as being mild to moderate. Long-term safety studies are ongoing, with emphasis on evaluating the impact of INH therapy on pulmonary function and immune responses. Although small, reversible decreases in pulmonary diffusion capacity (DL(co)) and FEV1 have been reported in response to INH, pulmonary function and structure do not appear to be affected in any clinically significant way. While insulin antibodies are increased in INH therapy, these antibodies have not been correlated with haemoglobin A1c (HbA1c), insulin dosage, hypoglycaemia, pulmonary function or adverse events. Nevertheless, properly controlled, long-term studies will best answer any remaining concerns. From the patient's perspective, INH therapy is preferred by the majority of patients over conventional SC insulin therapy. Studies have shown that patients prefer INH therapy, because it provides greater lifestyle flexibility and social acceptability while at the same time avoiding the pain associated with injection. Thus, after more than 80 years during which the injection route has been the only means of administering insulin, patients and physicians may soon avail themselves of another valuable tool in management of diabetes.

FlexPen®: Addressing issues of confidence andconvenience in insulin delivery

BACKGROUND

In people with type 1 or type 2 diabetes, poor adherence to insulin therapy can compromise disease management. There are several reasons for poor adherence, including social embarrassment, inconvenience, needle anxiety, fear of injection pain, and complicated regimens. Attempts to facilitate implementation of insulin therapy and to improve treatment adherence have focused on expanding the choices and features of insulin delivery devices.

OBJECTIVE

This review addresses the features, advantages, and disadvantages of insulin pen devices, with particular reference to FlexPen (Novo Nordisk, Bagsvaerd, Denmark), a prefilled/disposable pen device.

METHODS

Data from clinical studies published through June 2005 that evaluated the safety or efficacy of FlexPen in patients with type 1 or type 2 diabetes were reviewed. Key studies were selected following assessment of the sponsor's reference collection and as a result of MEDLINE searches (key words: FlexPen and pen devices). Particular attention was paid to studies comparing the FlexPen device with other pen devices. Peer-reviewed journal articles and published conference papers were included in the evaluation, as were reviews addressing the general use of these devices in the treatment of diabetes and associated issues.

RESULTS

Up to 65% of patients with type 1 or type 2 diabetes are not confident in their ability to effectively self-manage their disease. Only 23% of people with type 2 diabetes believe that insulin therapy would help them to better manage their disease. As many as 25% of people with diabetes who require insulin describe some anxiety regarding self-injection. Other barriers to effective insulin therapy include fear of injection pain, weight gain, and hypoglycemia; feelings of failure and guilt; and lack of motivation.

CONCLUSIONS

Insulin pen devices are discreet and offer patients convenience and flexibility. These features may give patients the confidence to overcome issues of needle anxiety and the social embarrassment associated with self-injection and, therefore, may lead to improved adherence to recommended insulin dosing schedules and compliance with multiple-injection regimens.