A Senate committee has started an investigation into the large drug price increases by Turing Pharmaceuticals and three other companies, responding to public concern about escalating prices for critical medicines.
The Senate’s Special Committee on Aging requested documents and information on Wednesday from Turing, Valeant Pharmaceuticals and two other drug makers already under scrutiny for recent price spikes.
Notably, the senators called for a face-to-face meeting with the chief of Turing, Martin Shkreli, “as soon as it is practicable.” A former hedge fund manager, Mr. Shkreli has become the public face of the pricing controversy, after his company raised the price of the anti-infection drug Daraprim by more than 5,000 percent.
The drug, which Turing acquired in August, is used in the United States to treat toxoplasmosis, a parasitic infection that can be particularly dangerous for pregnant women and patients with H.I.V.
Turing said in an email: “We are reviewing the committee’s request and, as we have and continue to do with similar congressional inquiries, we look forward to having an open and honest dialogue about drug pricing.”
Separately, Democrats in the House of Representatives called on their Republican colleagues to summon the Turing and Valeant chiefs to a congressional hearing and issue subpoenas to collect documents from their companies. Both firms have refused to turn over documents requested by Democrats on the House oversight committee.
Valeant is already under investigation by several members of Congress for its general business strategy, which involves buying smaller drug developers and then significantly raising the prices of their medicines.
Both Turing and Valeant have also received multiple subpoenas from federal prosecutors seeking information about drug pricing and other policies.
Senators Susan Collins, Republican of Maine, and Claire McCaskill, Democrat of Missouri, said a hearing on the issue was tentatively scheduled for Dec. 9. Ms. Collins is chairwoman of the aging committee, and Ms. McCaskill is its ranking Democrat.
“We need to get to the bottom of why we’re seeing huge spikes in drug prices that seemingly have no relationship to research and development costs,” Ms. McCaskill said in a statement. She added that some of the increases resemble “little more than price gouging.”
The committee also sent letters to Retrophin of San Diego and Rodelis Therapeutics of Alpharetta, Ga. The lawmakers questioned Retrophin about its decision to raise the price of a kidney drug, Thiola, from $1.50 a tablet to $30. Company shares tumbled more than 13 percent on Wednesday to $18.90.
The letter to Rodelis questioned the company’s price increase on a tuberculosis drug by more than 2,000 percent to $10,800 a bottle.
Over all, prescription drug prices have been on the rise for years. From 2008 through 2014, average prices for the most widely used brand-name drugs jumped 128 percent, according to the prescription benefit manager Express Scripts Holding.
In 2014, Express Scripts estimated that total prescription drug spending in the United States increased 13 percent. Reasons include increasing research costs, insufficient competition and drug shortages.
Shares of Valeant Pharmaceuticals fell 6 percent to $91.98. The company’s stock has lost more than 60 percent of its value since August because of controversy about its drug-pricing schemes and ties to the specialty pharmacy Philidor Rx Services.
Philidor said last week it would shut down after Valeant and several major customers stopped dealing with the company.