Scientists strive to spare diabetics from the needle

New discoveries combined with noninvasive blood monitoring may lead to more people using insulin sooner, but a needle-free existence is still a long way off.

By Victoria Stagg Elliott, amednews staff. Sept. 17, 2001.

The concept of injected insulin therapy could someday become a thing of the past.

Both the discovery of a new polymer that may allow for an effective insulin pill and positive clinical trial results for inhaled insulin have increased the hope that the needle could once and for all be eliminated for people with diabetes.

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"There is a significant need for replacing the needles with some other way that would be less intrusive and less painful," said Nicholas A. Peppas, ScD, a professor of clinical and biomedical engineering at Purdue University, West Lafayette. He presented a paper on the polymer at last month's annual meeting of the American Chemical Society in Chicago.

He is not the first to take on this prickly challenge. But the decades-long hunt for alternative insulin delivery systems is littered with failures. Some have tried patches. Others have experimented with eye drops, suppositories, nasal sprays and skin implants. All have looked for the magic potion that could eliminate the needle, minimize patient discomfort and cut the amount of needles and sharps that end up in the waste stream.

"Don't hold your breath," said Philip Raskin, MD, director of the diabetes treatment center at the University of Texas Southwestern Medical Center in Dallas.

No delivery system has quite worked out better than the trusty needle and syringe, which has been delivering insulin to people with diabetes since its discovery in the 1920s. Modern versions are much tinier, but they are basically the same.

Breathe deep or swallow?

Recent developments, however, seem to offer new promise.

Dr. Peppas reported the development of a polymer that when used as a pill coating allowed insulin to be absorbed by the blood in rats and dogs without being destroyed by the digestive system. Purdue University researchers are now looking for industry partners to allow for further animal studies and early human studies.

Still, experts have serious hesitations about the prospects for such a new delivery method, primarily because accuracy in dosing is so crucial in controlling blood sugar.

"The needle is cheap," said Richard Hellman, MD, a Kansas City endocrinologist in private practice. "And more importantly, it's precise. The big question is whether the other methods are."

The pill coating presented at the American Chemical Society improves the amount of insulin that gets to a blood stream from 0.01% in an ordinary tablet to 16%. It is a long way from being useful to patients.

Meanwhile, an inhaled form of insulin is in stage three clinical trials. This concept contains worries about what a lifetime of inhaled insulin might do to lungs and how much of it would get to the blood stream if breathing is in any way impaired, for example, by smoking or respiratory infections. The inhaler is also significantly larger than the ubiquitous asthma inhaler and may not be as convenient as injectable insulin. Also, no one expects it to be used in isolation, particularly initially. Instead, it probably would be used in conjunction with insulin sensitizers or some injectable insulin.

"We certainly need more research before we suggest that everyone taking insulin switch to snorting it," Dr. Raskin said.

The external pump has been the only effective alternative to several needles a day. The device needs to be changed every three days and is not right for everyone. It does, however, have a lot of fans.

"Most people like that a lot, even though every two or three days they have to stick a needle in," Dr. Hellman said. "But they would rather do that than give multiple insulin injections."

Experts say the most likely candidates for inhaled or oral insulin may be those who are poorly controlled through diet, exercise or insulin-sensitizing pills or who put off using insulin, a last resort, as long as possible because of the needle. For many patients, though, the fear of the needle is more troubling than the needle itself.

"For a child facing diabetes for the first time, a needle is a very daunting type of device," Dr. Hellman said. "For an adult who has long-standing diabetes, the development of the need for insulin is often surprisingly to them less troublesome than they may have thought."

Other technologies

But many say that for some people with diabetes, the needle that delivers insulin is not the problem.

"A lot of people tell me: 'Doc, it's not the shots, it's the blood tests," Dr. Raskin said. "I'm not sure I would prick my finger once in my life, let alone four or five times a day. The biggest blessing to people with diabetes would be some less invasive way to measure blood glucose."

Some diabetics use an alternative system that pricks the forearm. Researchers are also looking into infrared and ultrasound testing.

The one that has the most promise is the GlucoWatch Biographer, approved by the Food and Drug Administration in March for adults and expected to be in production by the end of this year. The device, manufactured by Cygnus Inc., Redwood City, Calif., is worn on the wrist like a watch.

Experts call it a good start rather than a solution. One finger stick is still required in order to calibrate the instrument, and half who used the item in clinical trials complained of skin irritation. It is also a bit bulky.

But doctors who treat people with diabetes say that the value in an item like the GlucoWatch may not be in the reduction of sharps use, but in the constant stream of information that you cannot get from a diabetics' usual three or four daily finger pricks.

"A single fingerstick measurement tells you what your sugar is now, but it doesn't tell you if you're going up or going down," said Robert Gabbay, MD, PhD, assistant professor at the Pennsylvania State University Medical School in Hershey.

Meanwhile, those who treat people with diabetes say the end of the needle is far off, but, if ever achieved, would be a welcome change.

"For almost everyone, given a choice, nearly all patients would prefer not to have a needle," Dr. Hellman said. "The pain is not so great, but people just hate the idea."

ADDITIONAL INFORMATION:

Panel recommends lower age for diabetes screening

Patients at high risk for diabetes should be screened for the disease from age 30, according to guidelines issued last month by the American College of Endocrinology and the American Assn. of Clinical Endocrinologists. Previous guidelines recommended screening at age 45 for most patients and suggested earlier screening for those at high risk, although an exact age for this group was never specified.

The move follows several studies finding that large numbers of diabetics are diagnosed after damage has already been done. Incidence of the disease also has increased dramatically among those in their 30s. According to the Centers for Disease Control and Prevention, the rate increased 76% from 1990 to 1998 among those 30-39 while increasing 33% in the general population.

The panel also recommended new targets for those who already have the disease. The A1C blood sugar test that determines how well blood sugar has been controlled over the past three months should now be 6.5% for the disease to be considered under control. Pre-meal and post-meal blood sugar targets were also lowered to 110 and 140, respectively.

Weblink

American College of Endocrinology/American Assn. of Clinical Endocrinologists Consensus Conference on Guidelines for Glycemic Control (http://www.aace.com/pub/press/releases/diabetesconsensuswhitepaper.php)