WASHINGTON (AP) — Fighting the problem of fake drugs will require creating a national drug-tracking system, the Institute of Medicine said Wednesday.

The call for putting medications through a chain of custody like U.S. courts require for evidence in a trial comes a week after the Food and Drug Administration warned doctors, for the third time in about a year, that it discovered a counterfeit batch of the cancer drug Avastin that lacked the real tumor-killing ingredient.