The subpoena was initially issued on Aug. 26. According to Morrisey, “Mylan initially agreed to cooperate, but has since failed to respond to the majority of the subpoena.”
"I have a statutory responsibility to investigate any potential antitrust violation,” Morrisey said in a statement today. “Consumers lose when competition doesn’t flourish. My office owes it to consumers to be their watchdog and turn over every rock to ensure fair play."
Mylan has a manufacturing plant in West Virginia and participated in the state's Medicaid program in which the company paid rebates on EpiPens purchased by Medicaid users.
In a statement to ABC News, a spokeswoman for Mylan said the company has been cooperating with the investigation.
“Mylan has received an inquiry and request for information from the West Virginia Attorney General relating to EpiPen Auto-Injector," a spokeswoman said. "Mylan has been cooperating and continues to cooperate by providing information in response to the AG’s inquiry."
During today's news conference, Morrisey said the company's decision to increase the price for the EpiPen auto-injector, used to help counteract life-threatening allergic reactions, was "outrageous."
"We all want to know why Mylan has decided to increase its price to the point of causing hardship for some customers," he added.
Mylan has faced scrutiny after the price of a two-pack EpiPen soared, rising from approximately $100 in 2009 to around $600, according to medical literature and various pharmacies nationwide.
Morrisey is investigating if Mylan was issuing Medicaid rebates for EpiPens at "non-innovator" levels, which are typically used for generic drugs, rather than at "innovator" levels, which are used for name-brand drugs. Since EpiPen is a name-brand drug, the company could face Medicaid fraud action if they were paying lower level "non-innovator" rebates, according to the court documents.
Additionally the company is being investigated for possible antitrust activities, according to the court documents.
Mylan CEO Heather Bresch is expected to testify on Wednesday at a congressional hearing about the significant price increase for EpiPens.