Shares of Nektar, which is developing the medicine with large drugmakers Pfizer Inc. and Aventis, jumped as much as 23 percent on hopes the new data would help the drug win approval.

Most diabetics (news - web sites) give themselves an insulin injection daily, an often painful ritual that can discourage patients from sticking with their course of treatment. An inhaled form of insulin would be more convenient and help patients comply with their regimen, industry analysts say.

Nektar, previously known as Inhale Therapeutics, also said the treatment, called Exubera, reduced blood sugar levels in diabetics more than a commonly used therapy in the late-stage, or Phase III trials.

The inhaled product was originally expected to be submitted to the U.S. Food and Drug Administration (news - web sites) in 2002 or even earlier, but was delayed because of concerns that it might hurt lung function, or patients' ability to breathe. Nektar did not announce a new filing timeline in its statement Monday.

The results of the trial were presented at an annual meeting of the American Diabetes Association in New Orleans. They showed that Exubera significantly reduced blood glucose levels in more patients than GlaxoSmithKline Plc.'s Avandia.

Avandia is designed to make the body's natural stores of insulin do a better job.

Many diabetics have a combination of two problems: insufficient production of insulin, which controls levels of glucose in the blood, and ineffective batches of the hormone in the body.

As a result, many diabetic patients take one drug for each problem, including insulin injections for the lack of insulin and an "insulin sensitizer" such as Avandia to make existing insulin work better.

Nektar, Pfizer and Aventis are racing other companies to reach the market first with an inhaled form of insulin.

Aradigm Corp., along with Denmark's Novo Nordisk, has a product in Phase III clinical trial testing, and Alkermes Inc. and Eli Lilly and Co. are in mid-stage, or Phase II, testing with a drug.