Martin Shkreli loves to talk.
Whether on Twitter, in online streaming videos or in interviews with the news media, Mr. Shkreli, a New York businessman, has shown little reserve when it comes to discussing the pending federal securities fraud charges against him, or his rationale for increasing the price of a decades-old drug by more than 5,000 percent at a pharmaceutical company he ran until last month.
On Tuesday, Mr. Shkreli, 32, will get his chance to talk some more. A congressional committee has served a subpoena on him and ordered him to appear for a hearing to discuss pricing trends and other developments in the drug industry, according to documents reviewed by The New York Times.
The subpoena directing Mr. Shkreli to appear before the House Committee on Oversight and Government Reform was served by email to one of his lawyers at Arnold & Porter on Jan. 11.
But whether or not Mr. Shkreli will appear on Tuesday, let alone testify, is an open question.
Wednesday afternoon, Senator Susan Collins, the chairwoman of the Senate Special Committee on Aging, took to the floor of the Senate, to provide an update on that committee’s own investigation into large increases in drug prices. Ms. Collins, a Maine Republican, said Mr. Shkreli had refused to comply with a committee subpoena sent on Dec. 24 seeking documents by asserting his Fifth Amendment right against self-incrimination.
Senator Claire McCaskill, a Missouri Democrat on the committee, followed Ms. Collins to the floor to say that while the right against self-incrimination is important, the documents being sought “have no connection to any criminal proceeding.”
As for Tuesday’s hearing in the House, also scheduled to testify are Howard B. Schiller, the interim chief executive of Valeant Pharmaceuticals, and Nancy Retzlaff, chief commercial officer of Turing Pharmaceuticals, the drug company that Mr. Shkreli formerly ran.
Mr. Schiller and Ms. Retzlaff are expected to appear voluntarily. Mr. Schiller was appointed by Valeant’s board to temporarily run the company after J. Michael Pearson, its chief executive, was hospitalized late last year with a severe case of pneumonia. Valeant has also been criticized for its pricing policies and is facing a federal inquiry as well as congressional scrutiny.
“Mr. Schiller looks forward to testifying and sharing with the committee how Valeant works to make its drugs available to the millions of patients who depend on them,” said Laurie W. Little, a spokeswoman for Valeant.
At a JPMorgan Chase health care conference last week, Mr. Schiller said he anticipated being called to testify before Congress and added, “you survive these things and then you move on.”
It is not known if Mr. Shkreli will attend the committee hearing with any lawyers. On Monday, one of his lawyers notified a federal judge in Brooklyn that Mr. Shkreli was replacing his entire legal team at Arnold & Porter and seeking to hire new counsel to represent him in the pending criminal securities fraud case.
When asked about the hearing and whether he would attend, Mr. Shkreli wrote in an email, “I made it clear that you are not to contact me ever again.”
But in a posting on Twitter later in the day, Mr. Shkreli wrote: “House busy whining to health care reporters about me appearing for their chitchat next week. Haven’t decided yet. Should I?”
There may be no legal risk to Mr. Shkreli in testifying about large price increases in the drug industry. The federal securities charges against him involve accusations that he defrauded investors in two former hedge funds he ran and are unrelated to accusations of price gouging by Turing.
Its decision to increase the price of the drug Daraprim a month after the company acquired it spurred outrage last fall from some politicians and media commentators. On Twitter, some people branded him the “bad boy of pharma.” Immediately after acquiring the rights to Daraprim, which has been used for decades to treat a life-threatening parasitic infection, Turing raised the price to $750 a tablet from $13.50.
But rather than be shamed by the outrage, Mr. Shkreli seemed to revel in it and defended the decision. Over the next several months, he frequently justified the price increase on Twitter and appeared in many news articles.
He has maintained his public persona even after prosecutors in Brooklyn filed a criminal complaint in mid-December.
In advance of Tuesday’s hearing, Turing and its interim chief executive, Ron Tilles, were asked to produce documents relating to Daraprim from Jan. 1 to Dec. 31, 2015, according to a copy of a Jan. 6 letter sent by the committee. The letter, signed by Representatives Jason Chaffetz, a Republican of Utah and the committee’s chairman, and its top Democrat, Elijah Cummings of Maryland, also asked for “copies of all documents previously produced” in response to requests from other government agencies.
Mr. Cummings, in a statement, said he looked forward to the hearing and having a chance to speak to Mr. Shkreli. “He claims publicly that he wants to explain to Congress how drug pricing works,” Mr. Cummings said. “On Tuesday, he will get his chance.”