Inhaled Insulin for Diabetes Therapy Approved by FDA
The first inhaled insulin treatment for diabetes, called Exubera®, recently won approval from the US Food and Drug Administration (FDA).
Insulin is the hormone that converts blood sugar, called glucose, into energy for cells in the body.
The long-awaited action by the FDA means millions of people with both type 1 and type 2 diabetes may have the option of avoiding the needles and countless injections that have marked their lives so far.
Type 1 diabetes, in which the body's insulin-producing capabilities are limited or non-existent, is not linked to body weight.
Type 2 diabetes has become a global epidemic, affecting some 12 million people in the US alone.
The condition, which develops when the pancreas does not produce enough insulin or the body cannot use the hormone efficiently, is strongly associated with overweight and obesity.
While some people can manage their type 2 diabetes through diet and exercise, others must rely on insulin injections.
If left uncontrolled, either type of diabetes can lead to a multitude of complications, including amputations, blindness, kidney disease, heart attack, and strokes.
"This is the first new insulin delivery option introduced since the discovery of this drug in the 1920s," says Dr. Steve Galson, director of the FDA Center for Drug Evaluation and Research.
"There are more than 5 million Americans who take insulin injections every day, and Exubera may be an option for many of these patients," says Dr. Galson. "It will not replace all injectable insulin. . . It's a very highly innovative product that has the potential to improve the quality of life of millions of Americans with diabetes."
Dr. Robert Rapaport, director of the division of pediatric endocrinology at Mount Sinai School of Medicine, says, "This is highly positive. It will be a major advance for individuals with diabetes, both children and adults."
According to the FDA-approved medication guide that will accompany Exubera prescriptions, children and teenagers should not use Exubera, because it has not been tested enough in persons younger than 18.
"I think there will be some longstanding questions about its ultimate safety because it's the first inhaled medication that will be used like this," notes Dr. Rapaport. "But, assuming the safety profile will be good, it will be a major advance."
Adds Dr. Stuart Weiss, an assistant clinical professor of medicine at New York University School of Medicine: "There are still some questions as to lung function and diffusion capacity, and smokers can't use it.
"There are all sorts of things to be concerned about," says Dr. Weiss. "It's going to take a few years to see whether or not it's as safe as all that."
The announcement follows European regulators' approval of Exubera.
The first commercial insulin hit the market in the 1920s. Since then, the gold standard for treatment of type 1 diabetes and more advanced type 2 diabetes has been insulin, injected before meals.
In the intervening years, new types of insulin formulations and devices have made the process more efficient.
"Needles are way, way smaller, syringes are easier to use, pen devices are very discreet, all sorts of delivery devices are very impressive," says Dr. Weiss. But the premise has remained the same - delivery by injection.
Exubera, on the other hand, is a dry powder formulation of insulin inhaled into the lungs through the mouth.
Like injectable insulin, it is administered before meals using a small, hand-held device.
Studies on safety and effectiveness were done on more than 2,500 adults with type 1 and type 2 diabetes. The medication, manufactured by Pfizer Inc., was as effective as injectable insulin for control of blood sugar, the company states.
Pfizer apparently delayed Exubera's application for US approval for three years to finish safety studies, say experts.
"Because this is a new way to deliver insulin to patients, it has been extensively studied with respect to safety and efficacy," says Dr. Robert Meyer, director of the FDA Office of Drug Evaluation II, which oversees the division of Metabolic and Endocrine Drugs.
"We have a large amount of data from the clinical trials speaking to the safety of this product overall, and safety in the lungs as well," says Dr. Meyer. "In addition, there are ongoing, continuing trials to monitor safety that will be reported after approval.
"We feel that there is an extensive and reasonable safety database to allow us to make a determination of efficacy and safety for patients without underlying lung disease and who do not smoke," notes Dr. Meyer.
In those clinical studies, Exubera reached peak insulin concentration more quickly than some insulins, called regular insulin, administered by injection.
Peak insulin levels were achieved at 49 minutes, on average, with Exubera, compared to 105 minutes, on average, with regular insulin, the FDA states.
Prescriptions for Exubera will be accompanied by a "Medication Guide" containing FDA-approved information written especially for patients, the agency said.
Like any insulin product, Exubera has a side effect of low blood sugar. Thus, persons with diabetes should carefully monitor their blood sugar regularly.
Other side effects associated with Exubera in clinical trials included cough, shortness of breath, sore throat, and dry mouth, the FDA reports.
Exubera should not be used by smokers or someone who quit smoking within the last six months. The medication is also not recommended in people with asthma, bronchitis, or emphysema.
Baseline tests for lung function are recommended before beginning treatment, six months after that, and then repeated annually, according to the FDA.
Inhaled insulin is unlikely to completely replace injectable insulin. But, for many people, it may greatly improve glucose control.
"It's very hard to predict what the impact will be," notes Dr. Weiss. "A lot of people who need to be on insulin are not on insulin. For that type 2 diabetic who is afraid of needles or will not take a shot, this is an ideal product.
"The problem is it doesn't address the root cause of diabetes," he says. "It could become another treatment that will cause people to overeat and under-exercise."
Exubera is also unlikely to be the only inhaled insulin on the market for long - other manufacturers of inhaled therapies are developing their own versions.
Always consult your physician for more information.
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Insulin has to enter the body's bloodstream to be effective. This is accomplished through injections into the fat layer - usually in the arm, thigh, or abdomen.
Different sites on the body allow the insulin to enter at different rates.
Insulin injected into the abdominal wall works the fastest, whereas injection into the thigh works the slowest.
Insulin must be administered to the body via an injection and cannot be taken by mouth because it is destroyed in the stomach during digestion.
The timing of insulin injections is very important. Insulin usually needs to be administered before mealtimes - before sugar from a meal starts to enter the bloodstream.
Always consult your physician concerning your individual insulin treatment, including injection sites, dosage, frequency, and specific times of administration.
There are many types of insulin injection devices available.
Some examples of devices include:
syringe
The syringe is the most common device used to administer insulin. The needle of the syringe is placed under the skin, and the insulin is injected.
insulin pen
Often used for multiple daily doses of insulin, the insulin pen holds a cartridge with insulin.
The pen, which looks like a writing pen, has a small needle at the tip. A dial on the pen allows the user to set the appropriate dosage.
A plunger on the other end of the pen is used to actually deliver or inject the insulin.
insulin jet injector
An insulin jet injector looks like a large pen.
The injector uses a mechanism to produce high-pressure air to "spray" the insulin through the skin. Insulin jet injectors may be an option for people who do not tolerate needles.
external insulin pump
An insulin pump is a device that pumps insulin continuously through plastic tubing attached to a needle under the skin near the abdomen.
The pump is small enough to be worn on a belt or in a pocket.
Always consult your physician for more information.
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