He's studying leucovorin, an inexpensive, generic drug derived from folic acid, also known as folate or vitamin B9. Leucovorin is currently prescribed to ease the side effects of cancer chemotherapy.

Mason Conner, a five-year-old previously nonverbal autistic boy from Arizona, finally said his first words just days after he started taking a cheap drug normally given to cancer patients.

He's studying leucovorin, an inexpensive, generic drug derived from folic acid, also known as folate or vitamin B9. Leucovorin is currently prescribed to ease the side effects of cancer chemotherapy.

An off-label prescription drug has been shown to help children with autism gain the ability to speak. Leucovorin is used for cancer patients, but doctors are pushing for its approval for autism.

Frye first turned to leucovorin as a potential treatment in the early 2000s after observing a striking pattern in children with autism. “I started to realize that the neurochemistry in the brain ...