Trevor Foltz was six months old last fall, fresh off a visit to Disney World in Orlando, when the spasms first began.

Healthy until that point in his life, he began thrusting backward in his car seat, repeatedly and forcefully, as he rode with his parents north toward home in Rhode Island. "I thought it was temper tantrums," says his mother, Danielle. The next day, at home, Trevor was hit with a series of 40 convulsions and rushed to the hospital, where he was diagnosed with infantile spasms, a rare form of epilepsy. Treatment would cost $1,600 per vial of steroid drug H.P. Acthar Gel, and Trevor would need three of them.

As if the idea of a $4,800 tab wasn't bad enough, when the Foltzes submitted their claim, they found out the company that made the drug, Questcor Pharmaceuticals, had just recently jacked up the price—to $23,000 per vial, or $69,000 for a three-vial treatment—and the insurance company wasn't going to pay. And all the while, unbeknownst to anyone at that time, an alternative, for $15, existed.

On Thursday, the Joint Economic Committee will open hearings in Congress on dramatic price hikes for drugs used to treat children, with a focus on companies such as Questcor and Ovation Pharmaceuticals, which in 2006 bought rights to a drug that treats heart problems in premature infants, and increased the price 1,800 percent to $1,875 per three-vial treatment.

"We need answers to why a company would increase the price of a drug 18-fold when costs related to marketing, physician education, and research appear stable," says hearing chair Amy Klobuchar, a Democratic senator from Minnesota.

Politicians say they are not opposed to drug companies earning strong returns on the costs of researching innovative drugs, and understand the high prices of many medications. But they are investigating whether some companies are price-gouging, concerned more about executive stock options than about running innovative companies.

Some of those drugs, like Questcor's, are decades-old drugs that were bought on the cheap and redesignated under the federal government's Orphan Drug Act, which marks its 25th anniversary this year. Not infrequently, the drugs' new owners pass on big price hikes to consumers.

At Questcor, the increase is explained as the cost of doing business with an orphan drug.

"The company was heading toward bankruptcy," says Steve Cartt, executive vice president for business development at Questcor, which is based in Union City, California, an industrial enclave on the San Francisco Bay.

"The whole rationale for the price increase was to ensure availability of the product," says Cartt. "We talked to physicians. They wanted the drug to be available. The choice was risk of availability or a price increase."

Originally approved for multiple sclerosis in 1952, Acthar Gel had been owned by pharma giant Aventis, which was losing money on it, when the 11-year-old Questcor acquired it in 2001. Questcor too failed to gain traction with M.S. patients, so it sought a new track.