WASHINGTON (CNNMoney.com) - Eli Lilly & Co. and Amylin, makers of the diabetes treatment Byetta, reported Saturday that a more convenient-to-use but experimental version of the drug successfully reduces blood-sugar levels.

Byetta, a potential blockbuster, has been on the market since June 1, 2005 to help diabetics with type 2, or the most common type of diabetes, control blood-sugar levels. The drug is injected twice a day, but a study released at the annual conference of the American Diabetes Association showed that an experimental once-a-week version is also effective.

The study showed that the long-acting release, or LAR, version of Byetta successfully controlled blood-sugar levels in 86 percent of patients taking high doses, compared to 33 percent with lower doses and 2 percent with placebo. This study was conducted on 45 patients over 15 weeks by Lilly (Research), an Indianapolis drugmaker, Amylin (Research), a San Diego biotech, and Cambridge, Mass.-based partner Alkermes (Research).

Continuing the original study that led to FDA approval, Lilly and Amylin also announced that 50 percent of Byetta patients successfully reduced blood-sugar levels over two years to a medically acceptable target and lost an average of 10 pounds.

In an additional study released Saturday, Lilly and Amylin said that Byetta, when used with TZDs, or pills that help the body use insulin, alone or in combination with metformin, a generic blood-sugar drug, successfully reduced blood sugar to a medically acceptable target 62 percent of the time.

Sales from Byetta, which is derived from the saliva of the Gila monster, totaled $68 million in the first quarter, which was split between Lilly and Amylin. Philip Nadeau, analyst for Cowen & Co., projects that annual sales will total $400 million in 2006 and $1.5 billion by 2010, to be divided among the two companies.

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