For diabetic patients reluctant to use insulin for fear of daily injections, their prayers may have been answered. Following years of setbacks and delays, the first new insulin delivery option in more than 80 years, Exubera (insulin human [rDNA origin]) Inhalation Powder from Pfizer Inc., received Food & Drug Administration approval in late January for the treatment of adults with Type 1 and Type 2 diabetes.

"More than five million Americans take insulin injections everyday, and Exubera might be an option for these patients," said Steven Galson, M.D., MPH, director of the FDA Center for Drug Evaluation & Research, at a press conference announcing the approval. "This highly innovative product has the potential to improve the quality of life for millions of Americans. It's a form of short-acting insulin that patients typically take to help manage their blood sugar levels at mealtime." But for those patients who also require long-acting insulin, this product will not totally replace injectable insulin.

According to the agency, the inhaled insulin reaches a peak concentration more quickly than insulin administered by subcutaneous injection (49 minutes vs. 105 minutes). Exubera's prescribing information states that the glucose-lowering effect of the drug occurs within 10 to 20 minutes, the maximum effect occurs about two hours after inhalation, and the duration of activity lasts approximately six hours. In some patients, Exubera may be an option for replacing regular insulin.

Exubera

Nektar Therapeutics, which developed the product in partnership with Pfizer, said it determined that existing inhalers for asthma medications were not appropriate for the delivery of insulin. The company subsequently developed a pulmonary device that disperses the insulin powder into an inhaler from a unique, double-foiled blister pack. Each blister pack will store and protect the insulin powder from moisture for up to two years.

Exubera is "not for everybody," said Robert J. Meyer, M.D., FDA's director of the Office of Drug Evaluation II, which oversees the division of metabolic and endocrine drugs. "In smokers, there is much higher (two- to fivefold) absorption of insulin, and more of the drug gets into the bloodstream in these patients." Because it was felt that this absorption would not always be predictable, it is therefore contraindicated in this population. Patients who have stopped smoking recently (within the past six months) should also not use the inhaled insulin.

In addition, Exubera should not be used in patients with chronic lung disease, such as asthma or chronic obstructive pulmonary disease (COPD), due to a lack of final safety and efficacy data. Side effects during clinical trials included hypoglycemia, cough, dry mouth, and chest discomfort. The coughing generally occurred within seconds to minutes after inhalation of the powder and tended to lessen over time in patients who continued to use the drug.

As part of the postmarketing commitment, Pfizer is required to perform a trial in 5,000 patients with either type of diabetes to evaluate lung function while using the inhaler. The company will also continue to study the drug in patients with asthma and COPD and monitor the effectiveness of Exubera's labeling in preventing its use in smokers. The FDA said modification in the labeling may be necessary if smokers are prescribed the drug despite current warnings.

Exubera will be available in 1- and 3-mg blisters. With each prescription for Exubera, R.Ph.s will be required to dispense an FDA-approved medication guide containing information written especially for patients. Dosage charts comparing regular insulin doses with those of Exubera are in the prescribing information.

Pfizer assures that the inhaler will be available by mid-2006. Patients and healthcare providers can call (1)-800-EXUBERA for further information.