WellPoint Health Networks Inc., one of California’s...

WellPoint Health Networks Inc., one of California’s biggest health insurers, said the U.S. government has subpoenaed documents about its relationship with TAP Pharmaceutical Products Inc.

The subpoena, which seeks information related to TAP’s drugs Lupron and Prevacid, was received April 22 from the U.S. attorney’s office in Boston, WellPoint said in a filing with the Securities and Exchange Commission. WellPoint said the subpoena involves a unit that manages pharmacy benefits and said the company isn’t a target of the investigation.

Pharmacy benefit managers Caremark Rx Inc. and Express Scripts Inc. also said this month that they have received subpoenas from the same U.S. attorney’s office concerning their relationships with TAP, a venture of Japan’s Takeda Chemical Industries Ltd. and Abbott Laboratories. Those subpoenas also concerned the cancer drug Lupron and the ulcer drug Prevacid.

Thousand Oaks-based WellPoint said it is complying with the law and will cooperate with any investigation. Its shares closed off 90 cents at $71.97 on the Big Board.