A Worcester, Mass. newspaper, interviewed a senior endocrinologist at the Joslin Diabetes Center in Boston about the potential problems and pitfalls of oral insulin delivery.

Dr. Richard A. Jackson (inset, left) explained that “a chief concern in developing oral insulin products is ensuring dosage accuracy. Insulin levels are especially sensitive,” and experience has proven that injecting insulin subcutaneously using needles delivers accurate dosing.

“Small variances in the dosing and the speed of absorption is more important for insulin than other things. If absorption through the mouth varies by 15 percent, that’s a lot,” he said.

Guess what? This concern should apply to Pfizer’s Exubera inhaled insulin, as well as other potential oral insulin delivery products currently in the pipeline undergoing clinical trials.
These include Canadian-based Generex Biotechnology Corp.’s Oral-lyn, Mannkind’s Technosphere inhaled insulin, and the Alkermes / Eli Lilly & Co. AIR inhaled insulin — all of which are undergoing clinical trials.
Dr. Jackson emphasized that a critical issues is “whether [orally delivered insulin products] can achieve the accuracy and be consistent about how much is absorbed in the mouth.”

Here is a rather cheeky concept for an Exubera ad from blogger John S.

This concept is not likely to ever be approved by Pfizer.

U.S. Department of Veterans Affairs (’V.A.’) has some fascinating conditions associated with the agency’s formulary list for approving health plan members’ use of Pfizer’s Exubera inhaled insulin.

Both of these conditions must be met:

• Doctor’s must have experience in managing diabetic patients on insulin
• Patient must have baseline spirometry and diffusing capacity for carbon monoxide (DLCO)

Also, the insured diabetic patient must either:

• Have severe persistent injection site problems such as lipohypertrophy, or
• Work in an environment that does not allow needles (e.g. prison guard)

In effect, it appears that the V.A.’s forumulary committee concluded that Exubera is generally not more effective than subcutaneous injectable insulin for either Type 1 or Type diabetics, and that working in a place where needles aren’t allowed would limit coverage of the diabetes drug to a relatively small class of insured patients.

You can read the V.A.’s full explanation of conditions associated with Exubera forumulary coverage by clicking here.