The companies said they expect to file for regulatory review of the drug in the United States, Europe and Japan in 2013 and will present detailed data from the trials this year and next.
The trials studied empagliflozin at 10 milligrams and 25 mg alone and in combination with other common diabetes treatments, such as metformin and Takeda Pharmaceutical Co's Actos, against a placebo. One of the trials tested the Lilly drug in patients with impaired kidney function.
Empagliflozin belongs to a new class of diabetes treatments called SGLT2 inhibitors that work by blocking reabsorption of glucose by the kidney and increases glucose excretion in the urine to lower blood sugar.
An advisory panel to the U.S. Food and Drug Administration this week is scheduled to discuss a Johnson & Johnson drug from the same class called canagliflozin, which is awaiting an approval decision.
Dapagliflozin, a drug from AstraZeneca Plc and Bristol-Myers Squibb Co that belongs to the same SGLT2 class, had earlier been rejected by the FDA over safety concerns, such as liver problems.
Lilly and Boehringer said incidence of adverse side effects was similar for placebo and both doses of empagliflozin. However, genital infections occurred more often with the treatment than with placebo, as had been seen in earlier studies with the class of drugs.
The empagliflozin Phase III program, including a large heart safety study, involves more that 14,500 patients, the companies said.
Boehringer and Lilly are collaborating on several diabetes drugs. On Monday, they said only Lilly would continue with development of one of the treatments, known as LY2605541.
About 371 million people worldwide are estimated to have diabetes. Type 2 is the most common form of the fast growing disease, accounting for about 90 percent of all cases.
Lilly shares were down about 0.4 percent at $51.34 in late morning trade on the New York Stock Exchange
(Reporting By Bill Berkrot and Caroline Humer; Editing by Maureen Bavdek and Sofina Mirza-Reid)