WASHINGTON - U.S. lawmakers are anxious to hear from 32-year-old pharmaceutical chief Martin Shkreli about severe hikes for a drug sold by a company that he acquired.

But it's unlikely the former CEO of Turing Pharmaceuticals will answer questions in his appearance Thursday before the House Oversight and Government Reform Committee. Shkreli, who has been widely scorned for hiking the price of a long-established and potentially lifesaving drug by more than 5,000 percent, says he's exercising his Fifth Amendment right against self-incrimination.

Shkreli is facing separate criminal charges of securities fraud related to another drug company.

Also going before lawmakers is the interim CEO of Canada's largest drugmaker, Valeant Pharmaceuticals. Both companies have bought and sharply raised prices for drugs taken by patients with heart problems, AIDS, cancer and other conditions.