UPDATE 1-US warns Takeda unit on cancer drug promotion

* Mailing overstated effectiveness of Velcade-FDA

* Company says will respond to the agency

WASHINGTON, June 23 (Reuters) - U.S. regulators have warned a Takeda Pharmaceutical Co (4502.T) unit about a misleading promotion for cancer drug Velcade, a letter released on Tuesday said.

A mailing from Takeda's Millennium Pharmaceuticals Inc unit overstated Velcade's effectiveness and failed to contain the appropriate information about its approved uses and risks, the Food and Drug Administration said in a letter to the company.

Millennium spokeswoman Lisa Adler said the company would respond to the FDA. "We are always committed to complying with all agency regulations," she said.

The FDA posted the letter, which was dated June 18, on the agency's website here

(Reporting by Lisa Richwine; Editing by Richard Chang)