On March 16, 2005, Amylin Pharmaceuticals, Inc., of San Diego, California, announced it had received FDA approval for Symlin (pramlintide acetate) injections to be used in conjunction with insulin to treat diabetes.

“Symlin provides a new option for many patients who, despite their best efforts with insulin therapy, continue to struggle to achieve their glucose control targets,” says Robert E. Ratner, MD, an investigator for the Symlin clinical studies, a vice president for scientific affairs at MedStar Research Institute and a professor of medicine at the Georgetown University Medical School.

What Is Symlin?

Symlin is a synthetic analog of human amylin, which is a naturally occurring hormone made in the beta cells of the pancreas, which also make insulin. Type 1s and insulin-using type 2s have amylin deficiency because they have destroyed or damaged beta cells. This, according to Steven Edelman, MD, an endocrinologist from San Diego, California, results in reduced secretion of both insulin and amylin after meals.

Symlin is groundbreaking for type 1s and insulin-using type 2s because it “mimics” certain physiological effects of amylin.

In short, Symlin replaces amylin deficiency.

“[Symlin] decreases the accelerated rate of gastric emptying, which is a characteristic of amylin deficiency,” says Harold Lebovitz, MD, professor of medicine at the division of endocrinology and metabolism/diabetes at the State University of New York Health Sciences Center in Brooklyn, New York. “There is an increase in satiety which reduces food intake, a decrease in [after-meal] glucagon secretion and a decrease in [after-meal] glucose excursions.”

In addition to having fewer blood glucose fluctuations and improving their control, Edelman says that patients taking Symlin will also lose weight.

“Normally, patients gain weight when they intensify their control,” says Edelman.

How Does It Work?

According to Amylin, Symlin is to be used at mealtime in patients with type 2 or type 1 diabetes who have failed to achieve desired glucose control despite optimal insulin therapy.

Symlin is a self-administered injection given prior to meals. According to Lebovitz, therapy starts with a low dose (15 micrograms in type 1s and 30 micrograms in type 2s) and titrated slowly to 60 micrograms in type 1s and 120 microgram in type 2s.

Edelman says that Symlin will eventually come in a pen delivery system, but for now it is available only in a vial. Patients are instructed to self-administer mealtime doses of Symlin subcutaneously using an insulin syringe including the correct “units” dosage conversion for the Symlin dosages in micrograms.

It is important to note that Symlin has a different chemistry (pH) than insulin; therefore, mixing it in the same syringe is not advisable.

What If Your Existing Regimen Is Working Well?

Symlin is indicated for use at mealtime for patients “who have failed to achieve desired blood glucose control despite optimal therapy.”

So what does this mean if your glucose control is successful with optimal insulin therapy?

“If it isn’t broke, don’t fix it,” says Edelman.

Symlin is not for people who are achieving their treatment targets. However, a March 1999 study that appeared in Diabetes Care found that approximately 74 percent of patients using insulin are not achieving A1Cs of less than 7%. For these people, Symlin is certainly a treatment option.

“If the A1C is good and the person’s blood sugar levels are not bouncing around all over the place and no weight needs to be lost, then you do not need Symlin,” says Edelman.

It is estimated that Symlin will be commercially available in June 2005. For more information, log on to www.amylin.com or call (858) 552-2200.

What Is Symlin and What Does It Do?

• Symlin is a diabetes medication used in patients with insulin-treated diabetes.
• Symlin is a synthetic analog of human amylin, a naturally occurring hormone that is made in the beta cells of the pancreas, which also produce insulin.
• The use of Symlin contributes to glucose control after meals.
• For more information and for complete prescribing information, log on to www.symlin.com.

How Is Symlin Used?

• Symlin is formulated for self-administration by injection prior to meals.
• Symlin is used at mealtimes in type 1s and insulin-treated type 2s who have failed to achieve desired glucose control despite optimal therapy.
• Symlin is available in a vial to be injected subcutaneously with a syringe. Insulin has a different chemistry (pH) than Symlin, so it cannot be mixed in the same syringe.
• According to Steven Edelman, MD, Symlin will eventually be available in a pen delivery system.

When using Symlin in conjunction with your insulin regimen, Harold Lebovitz, MD, says that the likely clinical consequences are

• Improved blood glucose control
• A reduction in food intake at meals
• A decrease in body weight

Important Safety Information Regarding Symlin

• Symlin is not intended for all patients with diabetes.
• Symlin is used with insulin and has been associated with an increased risk of insulin-induced severe hypoglycemia, particularly in patients with type 1 diabetes.
• When severe hypoglycemia associated with Symlin use occurs, it develops within three hours following a Symlin injection.
• If severe hypoglycemia occurs while operating a motor vehicle or heavy machinery or while engaging in other high-risk activities, serious injuries may occur. Appropriate patient selection, careful patient instruction and insulin dose adjustments are critical elements for reducing this risk.
• Adverse events commonly observed with Symlin when co-administered with insulin were gastrointestinal problems including nausea, which was the most frequently reported. The incidence of nausea was higher at the beginning of Symlin treatment and decreased with time in most patients. The incidence and severity of nausea are reduced when Symlin is gradually increased to the recommended doses.

Source: Amylin Pharmaceuticals

Amylin on a Roll

Type 2 Drug Also Approved

Continuing its momentum, on April 29, 2005, Amylin Pharmaceuticals also received FDA approval for Byetta (exenatide).

Indicated for people with type 2 diabetes “who have not achieved adequate control on metformin and/or a sulfonylurea,” Byetta is taken as a subcutaneous injection twice a day in combination with existing oral medications.

According to Amylin, which is co-marketing the drug with Eli Lilly and Company, Byetta (pronounced bye-A-tuh) is the first in a new class of medicines known as incretin mimetics. An incretin is a hormone released by the gut into the bloodstream in response to food. Incretin hormones help regulate blood glucose levels in the body.

Diabetes Health will do a longer article on Byetta in its July 2005 issue.

Practical Advice for Patients On Symlin Therapy
By Steven Edelman, MD

1. Start with a low dose and titrate slowly.
Symlin can cause nausea, anorexia and vomiting, especially in people with type 1 diabetes. It is extremely important not to rush the dose titration. In patients with type 1 diabetes, start with a mealtime dose of 15 micrograms, which is equivalent to 2.5 units on a traditional insulin syringe. If after one week there are no side effects, then it is safe to advance by 15 micrograms. If, on the other hand, the patient is experiencing nausea or other gastrointestinal side effects, do not increase the dose of Symlin, and wait until the side effects dissipate altogether. Patients with type 2 diabetes experience significantly fewer side effects, so the titration can start at 30 micrograms and you can titrate more quickly if the patient is asymptomatic.

2. Take Symlin as you start eating the main part of your meal.
Symlin seems to produce its satiety effect within 10 to 15 minutes after injection, although each patient’s response may vary. If the meal starts with an appetizer or soup and salad, the patient can consider waiting until the main course is served. This recommendation comes from feedback given during the clinical trials. If Symlin is taken too early and the pre-meal insulin dose has already been given, the risk of after-meal hypoglycemia may go up.

3. Decrease the amount of rapid-acting insulin analog (Humalog, NovoLog or Apidra) by 30 to 50 percent when initiating Symlin.
This precaution is especially true for patients with type 1 diabetes. Symlin works to not only reduce glucose levels; it may also lead to a reduction in food intake greater than anticipated by a patient who has recently started taking Symlin. Further adjustments of the insulin dose either up or down should be based on home glucose monitoring results and experience with Symlin.

4. Timing of the insulin dose is important.
Many patients who have experience with Symlin take their rapid-acting insulin analog as they approach the end of their meal. The reason is that they will know how much and what types of food they will be eating, so the insulin dose calculation using carbohydrate counting or other means will be more accurate. In addition, because Symlin delays gastric emptying, the peak in glucose after meals may overlap with the peak action of the rapid-acting insulin analogs when given a little later than the beginning of the meal.

5. Be prepared to be satisfied sooner when initiating Symlin.
Satiety is the feeling of being satisfied. Symlin-induced satiety is best described as a lack of desire to continue eating because you feel that you have had enough food. It is not feeling “stuffed,” as many people feel after overeating on Thanksgiving. It is simply the lack of desire to eat any more. Many subjects who have used Symlin stop eating second and third helpings and take home doggie bags with restaurant leftovers on a regular basis. Many subjects have reported struggling to convince themselves to take their Symlin dose when dining at an expensive or all-you-can-eat restaurant.

Amylin and Insulin: The Beta Cell Partner Hormones

Making Sense of Some Words That End With ‘lin’

Amylin reduces the amount of glucose that shows up in the bloodstream by reducing the amount of food consumed. In turn, this prevents glucagon (which leads to glucose production) from being secreted and slows down the rate that the stomach dumps food into the small intestine. This leads to lower after-meal blood glucose values.

Insulin, on the other hand, works “on the other end,” allowing the tissues to suck up the glucose out of the bloodstream.

Symlin allows amylin and insulin to now work together “on both ends,” which allows a lower dose of insulin and, after adjustments are made, leads to fewer fluctuations and fewer occurrences of hypoglycemia.

Source: Steven Edelman, MD