In June 1998, patients with chronic myeloid leukemia (CML), a blood cancer, began taking capsules labelled with a code: STI571.

Among those given 300 mg a day or more, 53 of 54 saw their blood counts return to normal.

The FDA approved the drug, now called imatinib and sold as Gleevec, in May 2001.

Where had that capsule come from?