The way in vitro companion diagnostics for cancer drugs are labeled sometimes presents a challenge for oncology care, said FDA Commissioner Scott Gottlieb in announcing new guidance to tackle the problem.
In vitro diagnostic test approvals are frequently supported by studies of one specific drug. That means the labeling often reflects the test’s use with just that medicine. As a result, the drug’s labeling may also reflect its use with only that test.
Gottlieb noted an increase in new drugs targeting specific molecular markers that drive the growth and spread of cancer, sometimes with multiple drugs in a class of medicines targeting the same marker in nearly the same way. Because of this, a diagnostic test that helps deliver one specific drug could be well-equipped to guide the delivery of all drugs in that class, he said.