The announcement on the new drug (which only needs to be taken once a week) sent Amylin shares up as much as 19 percent on Tuesday, while shares of Lilly, the much larger drugmaker, were 2 percent higher.

Amylin is hoping to file for regulatory approval of once weekly Byetta by the end of the second quarter. The currently approved version of Byetta available in the market is typically injected twice a day.

The 26-week study comprising 491 patients compared Byetta LAR, also known as exenatide once weekly, with maximum doses of Merck & Co Inc’s Januvia, known chemically as sitagliptin, and pioglitazone, sold under the brand name Actos by Japan’s Takeda Pharmaceutical Co Ltd.

The type 2 diabetes patients taking Byetta LAR experienced a reduction in A1C ( a measure of average blood sugar) over three months of 1.7 percentage points from baseline, compared to a reduction of 1.0 percentage point for Januvia and 1.4 percentage points for Actos, according to Amylin.

These results of the DURATION-2 trial were deemed to be statistically significant.

“Today’s data confirm the superiority of exenatide LAR, which has only been assumed to this date, but not tested head- to-head versus existing oral therapies,” Lazard Capital Markets analyst Matthew Osborne wrote in a recent research note.

“We believe data from DURATION-3 trial comparing exenatide LAR versus Lantus could show similar superiority, or at least similar A1C, but with greater weight loss,” Osborne said. The drug Lantus is sold by French drugmaker Sanofi-Aventis SA.

In addition to its advantage in blood sugar control, the Byetta patients also lost an average of 6.2 pounds (2.8 kg) at 26 weeks compared with a loss of 1.9 pounds (0.9 kg) for Januvia and a weight gain of 7.4 pounds (3.4 kg) for Actos.

Weight loss is a very desirable side effect for diabetes treatments as obesity is one of the leading causes of the disease and some drug treatments, such as Actos, can cause weight gain. Patients who took part in this study were generally not obese, which makes the weigh loss even more significant.

“A once-weekly therapy that helps patients achieve A1C targets, with the added benefits of weight loss and no major hypoglycemia, could provide patients with an important option to improve their diabetes care,” Dr Richard Bergenstal, executive director of the International Diabetes Center, said in a statement.

During the 26-week study, the most frequently reported adverse effects amongst Byetta LAR users were nausea and diarrhea, which was similar to Januvia. Upper respiratory tract infections and peripheral edema were the most frequently reported adverse effects reported by those taking Actos in the study.

There were no cases of pancreatitis, or inflammation of the pancreas, seen with Byetta LAR patients in the study, which should be viewed as very good news as Byetta carries a warning about rare cases of the condition. Any cases of panceatitus that crop up in Byetta LAR studies could arouse extra scrutiny from health regulators making an approval decision.

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