Updated to include the Senate Judiciary Committee’s response.

Mylan (NDSQ:MYL) declined to testify at a U.S. Senate committee regarding its $465 million pending settlement to deal with charges that it underpaid government healthcare programs when it misclassified its EpiPen injector as a generic.

The Canonsburg, Pa.-based company penned a letter to the Senate Judiciary Committee Nov. 18, saying it would not testify because the matter of its settlement with the government is still pending.

“Further, we understand that representatives of those government agencies have confirmed to the committee that they are not able to send a witness to testify or provide further information about this matter while it is pending,” Mylan said in the letter.

Chairman Sen. Chuck Grassley (R-Iowa) said in a statement that Mylan was “ducking responsibility.” Grassley had scheduled the hearing for the end of this month.

“This seems to contradict Mylan’s claim that all potential liability claims have been resolved,” Grassley wrote.

Mylan is working to finalize a settlement with the U.S. government over Medicaid rebates for its EpiPen emergency allergy treatment. The company reported in October that it would pay a $465 million settlement, but the U.S. government has not confirmed the agreement.

The company has been under fire since August, when reports surfaced that it had raised the price of its device by 500% over the past decade. Bresch has since testified before Congress about the company’s pricing strategies, but some politicians are calling on regulatory groups to investigate.

Grassley wrote to the Securities and Exchange Commission yesterday to encourage an investigation, if it isn’t doing so already. “One way or another, I intend to get answers for patients and tax payers,” Grassley wrote in his statement.

The Senate Judiciary Committee said today that it will postpone the hearing while it “considers other avenues to ensure government and company witnesses participate.”