Oral Insulin Spray Showing Promise

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New formulation is absorbed by the buccal mucosa and rapidly enters the bloodstream

A form of needle-free insulin that is absorbed through the lining of the mouth may offer some diabetic patients a convenient new way to receive their insulin orally. This could help improve patient compliance with therapeutic regimens, thereby delaying progression of diabetes and its complications, according to researchers.

Clinical studies of the medication Oral-lyn (Generex Biotechnology Corp.) have shown that this form of delivery appears to be safe and effective, and it eliminates the pain and inconvenience of multiple insulin injections throughout the day. Oral-lyn insulin enters the bloodstream rapidly through the oral mucosa without deposition in the lungs. The product also allows for precise dosage control and easy handling, according to researchers.

“It is not like the inhaled insulin, so it doesn't get into the lungs,” said study investigator Philip Raskin, MD, professor of medicine at The University of Texas Southwestern Medical Center in Dallas. “People seem to like it, and it does seem to lower the blood sugar [the way] it is supposed to.”

Dr. Raskin is among the researchers involved in an international phase 3 study of 750 patients. The objective is to compare the efficacy of Oral-lyn with prandial injections of regular human insulin as measured by hemoglobin A1c. The trial is under way at 55 sites in the United States, Canada, Bulgaria, Russia, Poland, and Ukraine. Oral-lyn is already approved for commercial use in India and Ecuador.

Oral-lyn is a liquid form of human regular insulin that is sprayed into the mouth with a simple device similar to inhalers used by asthmatics. The oral insulin is buccally absorbed; the size of the spray particles precludes their entry into the lungs.

“It is probably more rapid-acting than human insulin given by injections but probably not more rapid-acting than fast-acting analogs given by injection,” Dr. Raskin told Renal & Urology News. “This is a way to give insulin without…an injection. This may benefit patients who are needle-phobic or anybody who would rather not get a shot.”

At The Endocrine Society's last annual meeting in San Francisco, Jaime Guevara-Aguirre, MD, of the Institute of Endocrinology IEMYR, Quito, Ecuador, presented findings from a one-year study on the oral insulin spray. The data showed that when administered basally and with meals to type 1 diabetics, the oral insulin spray attained lower preprandial glucose and hemoglobin A1c levels and lower fructosamine concentrations compared with a regimen of basal and preprandial insulin analogs.

The cost of insulin analogs, basal and preprandial, is higher than that of recombinant human insulin, but this greater expense can be justified by therapeutic advantages, Dr. Guevara-Aguirre and colleagues noted. The study concluded that human insulin, when delivered through the buccal mucosa, is not inferior to analogs in the long-term treatment of type 1 diabetes and could be used as a less costly alternative.

Endocrinologist George Griffing, MD, professor of internal medicine at Saint Louis University School of Medicine in Missouri, said these study findings are intriguing.

“We are always looking for new delivery methods, and patients always like to take their medications by mouth. So this approach does sound like a good avenue to pursue,” said Dr. Griffing, who has conducted studies with inhaled insulin. He noted, however, that he is concerned about the type of absorption enhancer being used in the oral formulation and the toxicities that might result from a lifetime of exposure.

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