On Monday, the company asked its outgoing Chief Executive Michael Pearson to cooperate with the U.S. Senate Committee on Aging after he failed to show up at a hearing on Friday.
The Senate committee said it may start contempt proceedings against Pearson after he failed to respond to a subpoena to appear for a deposition related to an investigation into drug pricing.
Pearson was unable to testify at a congressional hearing in February because he was on medical leave recovering from pneumonia.
Valeant was represented by interim CEO Howard Schiller, whom the company has since accused of "improper conduct" that contributed to a misstatement of the company's financial statements. Schiller has denied any wrongdoing.