Former pharmaceutical executive Martin Shkreli, a lightning rod for outrage over soaring U.S. prescription drug prices, pleaded not guilty on Monday to an additional criminal charge that federal prosecutors filed against him last week.

Shkreli, 33, was indicted in December on seven criminal counts, including securities fraud. Prosecutors on Friday added an eighth charge, saying Shkreli tried to conceal from investors his control over shares in Retrophin Inc.

Evan Greebel, former outside counsel to Retrophin, also pleaded not guilty to the charge at a court hearing in the New York City borough of Brooklyn. Greebel faces two counts in all.

Shkreli last year sparked outrage among patients, medical societies and U.S. lawmakers after another company he ran, Turing Pharmaceuticals, raised the price of Daraprim by more than 5,000 percent to $750 a pill.

In December, U.S. authorities arrested him on fraud charges unrelated to the pricing of Daraprim, saying he ran his investment funds and companies almost like a Ponzi scheme.

U.S. District Judge Kiyo Matsumoto declined during Monday's hearing to set a trial date for Shkreli and Greebel but said she was considering an early 2017 time frame.