Martin Shkreli fired as CEO of KaloBios Pharmaceuticals

Martin Shkreli, the embattled health care businessman, has been let go by KaloBios Pharmaceuticals — one of the companies he had headed.

KaloBios, which has a market cap of less than $100 million, hasn't traded since last Thursday. It was halted about 10 minutes after news of Shkreli's arrest on fraud charges.

On Monday, the company said Shkreli was "terminated" as CEO and had resigned from the board.

The 32-year-old former hedge fund manager pleaded not guilty Thursday in Brooklyn federal court and was released on $5 million bail.

He was charged with securities fraud and conspiracy. Prosecutors say that from 2009 to 2014, Shkreli lost some of his hedge fund investors' money through bad trades. To pay back his disgruntled clients, he allegedly looted $11 million from another pharmaceutical company, Retrophin, where he was CEO.

"As alleged in the indictment, Shkreli essentially ran his companies like a Ponzi scheme, where he used each subsequent company to pay off the defrauded investors in the prior company," U.S. Attorney Robert Capers said on Thursday.

Shkreli was already widely reviled because a different drug company he founded, Turing Pharmaceuticals, raised the price of a life-saving drug from $13.50 to $750 per pill. He resigned as its CEO on Friday.

Turing announced on Friday that it had appointed a new interim chief executive to replace Shkreli.

Shkreli through his press relations firm said he is confident he will be cleared of all charges, adding that some of the charges involved "complex accounting matters" that authorities failed to understand.

The verified Twitter account for Shkreli was apparently hacked over the weekend, but those tweets were deleted midday Monday, and a new message was posted.

—The Associated Press contributed to this report.