June 11 (Bloomberg) -- House lawmakers will investigate Wyeth, the drugmaker purchased last year by Pfizer Inc., after reports the organ transplant drug Rapamune was illegally marketed for unapproved uses.

The House Oversight and Government Reform Committee said it will review whether the drug, Rapamune, was targeted at black patients for unapproved uses, according to a letter sent to Pfizer Chief Executive Office Jeffery Kindler. The committee is looking into whether Wyeth “aggressively encouraged the use of Rapamune to prevent organ rejection following heart, lung, liver, pancreas, and islet cell transplants, without FDA approval,” the committee said in a statement.

Rapamune is approved to help prevent the rejection of kidney transplants. Regulators last year said kidney transplant drugs must strengthen warnings about the risk of infections and the Food and Drug Administration said Rapamune may increase the risk of death and organ rejection if given during a liver transplant.

Representative Edolphus Towns, a New York Democrat and the committee chairman, asked Pfizer in the letter to Kindler to provide materials about whether Wyeth targeted specific hospitals for sale of the drug, whether the company tried to get patients to switch to Rapamune from other therapies and records relating to the drug’s sale. Pfizer was asked to respond by June 28.

“The company shares Chairman Towns’ commitment to protecting patients’ health and will cooperate fully with his inquiry,” Pfizer spokesman Christopher Loder said in an e-mail. “Wyeth is committed to ensuring that information provided to physicians on the uses, benefits and risks for Rapamune is consistent with its FDA-approved label.”

• Bloomberg News