Updated

Japan's Takeda Pharmaceutical Co Ltd said U.S. regulators had extended their review of its diabetes drug alogliptin, requesting additional data on what the company hopes will be the successor to its top-selling Actos drug.

Shares of Takeda fell as much as 2 percent after Japan's biggest drugmaker announced during Tokyo trading on Thursday that it had received the request from the U.S. Food and Drug Administration.

Actos lost patent protection in 2011, and generic versions are expected to hit the market later this year.

The FDA had previously rejected Takeda's application for alogliptin in June 2009, asking for more safety tests. Takeda resubmitted applications for both alogliptin and a combination therapy with Actos in July 2011.

Takeda said it believes it can supply the FDA with the necessary data from outside the United States as well as from its ongoing clinical trials.

"We will immediately request a meeting with the FDA to determine the appropriate next steps and are committed to addressing outstanding issues," Thomas Harris, vice president of regulatory affairs, said in a statement.

Alogliptin belongs to a relatively new class of diabetes drugs called DDP-4 inhibitors for the treatment of type 2 diabetes. It was approved in Japan last year and is marketed under the name Nesina.

Dipeptidyl peptidase-4 inhibitors work to enhance the body's ability to lower elevated levels of blood sugar.

Nearly 26 million people in the United States, or 6 percent of the population, have diabetes, with type 2 diabetes accounting for 90 percent to 95 percent of cases, according to the American Diabetes Association.

Global health care expenditures to treat and prevent diabetes and its complications were estimated at $376 billion in 2010, Takeda said.