Federal health officials last fall touted a new treatment for autism: leucovorin, a derivative of Vitamin B9 commonly used during cancer treatment.

But the drugmaker, GSK, this week asked the Food and Drug Administration to pull its application because it doesn't market the medication, The Wall Street Journal reported.

The company hasn't sold the drug since 1999, and a GSK spokeswoman said the company never intended to sell it again.

"Generic formulations of leucovorin are approved and are now able to add the treatment of cerebral folate transport deficiency in adult and pediatric patients" with a specific genetic variant, a GSK spokeswoman told the Journal, adding that the withdrawal was procedural.

Leucovorin prescriptions surged after Health and Human Services Secretary Robert F. Kennedy Jr. and FDA Commissioner Marty Makary touted the drug for autism, but parents were scrambling to find it.

Kennedy Jr. called it an "exciting therapy that may benefit large numbers of children who suffer from autism."

The FDA backed away from those claims last month, though, and the prescription drug got a label update for cerebral folate deficiency in the receptor 1 gene, a genetic condition that's estimated to affect only about 1 in 1 million people, but not for autism.

"Right now, we don't have sufficient data to say that we can establish efficacy for autism more broadly," a senior FDA official said last month.

"They really wanted a review of the data to support potential approval for some forms of autism. And in this case, the review was performed as was asked for, and the data that we had supported the approval for this specific indication," another senior FDA official said.

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