Results from DURATION-2, a 26-week test comparing the diabetic drugs Januvia, Actos, and experimental long-acting Byetta (Byetta LAR) show that Byetta produced lower A1c's and more weight loss than the other two drugs.

Sponsored by Byetta's co-manufacturers, Amylin Pharmaceuticals, Inc., and Eli Lilly and Co., the randomized, double-blind study tracked 491 type 2 patients over a six-month period. Patients received either Byetta LAR (exenatide), Januvia (the brand name for Merck & Co., Inc.'s sitagliptin), or Actos (the brand name for Takeda Pharmaceutical Co., Ltd's pioglitazone).

Patients taking Byetta LAR reduced their baseline A1c by 1.7%, compared to 1.4% for patients on Actos and 1.0% for those on Januvia. 

Over the 26 weeks, Byetta LAR recipients lost an average of 6.2 pounds, versus a 1.9-pound loss for Januvia patients. Those on Actos experienced a weight gain that averaged 7.4 pounds. 

Researchers conducting the study said that in general, the patients were not obese, a factor that made the weight loss associated with Byetta impressive. 

The most common adverse responses for both Byetta LAR and Januvia patients were nausea and diarrhea. Actos users reported upper respiratory tract infection and peripheral edema as the most common side effects. 

One crucial result was that there were no reported cases of pancreatitis or inflammation of the pancreas among Byetta LAR patients in the study. Among the estimated 700,000 users of the current version of Byetta, a twice-daily drug that has been on the market for four years, there have been 30 reported incidents of pancreatitis, including six fatalities. Although there is no evidence that the drug caused the disease, the FDA made Amylin and Lilly rewrite the warning labels on the drug.

The possible connection between Byetta use and pancreatitis has also made FDA scrutiny of Byetta LAR more intense. The drug, which is now before the agency for marketing approval, uses injectable time-release capsules to provide a continuous does of the drug over a seven-day period.

Byetta's makers are hoping that the long-acting form of the drug will nudge sales, which have been flat over the past year, by appealing to users who want the convenience of once-a-week injections instead of having to remember to inject the drug every morning and evening at mealtimes.