Two individuals — both infected by the single-celled parasitic protozoa Toxoplasma gondii —  “showed prompt, dramatic responses” after being started on a two-drug cocktail.

One of the drugs was pyrimethamine, also known by its brand name, daraprim. A recent dramatic medical advance? Not quite. This report — one of the earliest reported uses of the regimen for toxoplasmosis — appeared in the New England Journal of Medicine in 1957. Daraprim has been a first-line treatment for toxoplasmosis — a serious threat to the immunocompromised and to the newborns of infected women — ever since.

But when Turing Pharmaceuticals CEO Martin Shkreli saw daraprim, he didn’t see an immutably inexpensive, age-old drug — he saw a gold mine.