By The Associated Press

WASHINGTON — The Republican chairman of the Senate Judiciary Committee says he is considering a subpoena or another method of compelling testimony from the pharmaceutical company Mylan and federal officials.

Mylan, the Justice Department and the federal Centers for Medicare and Medicaid Services have refused to attend a hearing next week.

Sen. Charles Grassley of Iowa said in a statement Wednesday he is postponing the Nov. 30 hearing on a possible settlement between Mylan and the Justice Department over Mylan's life-saving EpiPen.

Grassley says "we must now consider compelling their participation."

Related: Mylan Agrees to Settle With DOJ for $465 Million Over EpiPens

Mylan says it agreed to pay $465 million to settle allegations it overbilled Medicaid for EpiPen. At issue is whether the product should have been classified as generic.

But Grassley says the Justice Department has said there is no "executed settlement."

In September, Mylan CEO Heather Bresch faced hours of intense questioning from members of the House Committee on Oversight and Government Reform, which convened to investigate the company's stratospheric price hikes,