WASHINGTON -- The companies behind the Byetta diabetes drug Saturday presented data they hope will play a role in convincing the Food and Drug Administration to approve an improved form and new uses of the drug.

The current form of Byetta, from

Eli Lilly

(LLY) - Get Report

and

Amylin Pharmaceuticals

(AMLN)

, was approved by the FDA in April and has been available in the U.S. for about 12 months. The drug stimulates the body to produce more insulin in response to elevated blood sugar levels. It also produces some weight loss, but its biggest drawback is that it must be injected twice a day, vs. other blood-sugar control medications that are pills.

Lilly and Amylin have enlisted

Alkermes

(ALKS) - Get Report

to help them make Byetta more convenient by turning it into a once-a-week injectable drug. They presented results of a small clinical study on Saturday, at the annual scientific session of the American Diabetes Association, that showed this experimental form of Byetta provided improved blood-sugar control for people with Type 2 diabetes, the most common form of the disease. In Type 2 diabetes, a body's cells are unable to use naturally produced insulin to convert sugar into energy.

The experimental follow-up to Byetta is called exentatide LAR, or long-acting release. Testing 45 patients who couldn't achieve blood-sugar control via a standard treatment or via diet and exercise, the companies compared the drug vs. a placebo over 15 weeks, followed by a 12-week safety monitoring period in which no drug was given. Researchers found that exenatide patients, especially those receiving the stronger of two doses, had a reduction in blood sugar levels and a reduction in weight vs. the placebo patients.

"These early results suggest exenatide LAR can be clinically beneficial with Type 2 diabetes," said Dr. Dennis Kim, senior director of medical affairs for Amylin and the study's author.

However, the companies will need tests covering many more patients to convince the FDA to approve the drug.

Amylin and Lilly also revealed results of a two-year study playing to Byetta's strong suit -- weight loss. The company looked at 283 patients who hadn't achieved blood-sugar control from their existing medications. The original clinical trial assessed people after 30 weeks, finding that the average weight loss of Byetta patients was five pounds. Researchers followed these patients for two years, determining that their average weight loss had improved to 10 pounds. During this follow-up period, patients took Byetta as well as their existing diabetes medications.

And because diabetics often take more than one medication to control blood sugar, Lilly and Amylin are seeking FDA approval to market Byetta as an add-on therapy to a class of drugs known as thiazolidinediones, or TZDs. These drugs make muscle cells more receptive to insulin, and they also reduce sugar production in the liver. Byetta, known as an incretin mimetic, works primarily by encouraging the pancreas to produce more insulin. The companies filed their application for the combination therapy earlier this year.

In clinical trial data presented Saturday, researchers compared Byetta plus a TZD vs. a TZD alone. The patients were tested for 16 weeks, and researchers said patients receiving the combination therapy had a bigger reduction in a measurement of blood-sugar levels vs. the TZD patients. Among those who completed the full study, the researchers said 62% of the combination group achieved a nationally-recognized acceptable blood sugar level while only 16% of the other group reached this level.

"These data indicate that the addition of Byetta to TZDs can be a clinically meaningful treatment for patients," said Dr. Bernard Zinman, director of the Leadership Sinai Center for Diabetes at Mount Sinai Hospital in Toronto, who was the lead author of the research. Some of these results were announced last year.