WASHINGTON (Reuters) - The U.S. Senate voted on Thursday to confirm five nominees for the Federal Trade Commission, the first commissioners chosen by President Donald Trump to be approved in the 15 months since his inauguration.

The president has been slow to fill the FTC posts, leaving the agency in the hands of two Obama holdovers. The confirmations were unanimous on a voice vote.

The Senate confirmed veteran antitrust lawyer Joe Simons, a Republican, who will chair the commission. He is a former competition director for the agency who is now at the law firm Paul, Weiss, Rifkind, Wharton & Garrison LLP.

Lawmakers also confirmed Republicans Christine Wilson, chief of staff to former FTC Chairman Tim Muris and a senior vice president for regulatory and international affairs at Delta Air Lines Inc, and Noah Phillips, chief counsel for Senator John Cornyn.

The Senate also confirmed Rohit Chopra, a former official at the Consumer Financial Protection Bureau, and Rebecca Slaughter, an aide to Senator Chuck Schumer, to fill the two Democratic seats.

Wilson may not be sworn in immediately since the seat she was nominated for is still occupied by acting Chairwoman Maureen Ohlhausen. Ohlhausen, a Republican appointed by Obama whose term ends in September, was nominated to be a judge but has not yet been confirmed.

The FTC works with the U.S. Justice Department to enforce antitrust law and investigates companies accused of deceptive advertising. One big merger before it currently is a proposed combination of industrial gases companies Praxair Inc and Linde AG.

The FTC is also reviewing whether Facebook violated a 2011 FTC consent decree over its privacy practices following allegations that Cambridge Analytica improperly gained access to user data for 50 million people without users being notified.

At the commissioners’ confirmation hearing, Simons said the FTC should be open to investigating big tech firms like Google or Facebook if they use their considerable clout inappropriately.

The FTC has been sharply criticized for settling with Google in early 2013 after a lengthy investigation into whether the company had manipulated search results to hurt rivals.

Simons also discussed the need for a drug pricing task force to identify unusual price increases.

Since January, the FTC has been run by two holdovers from the Obama administration: Ohlhausen and Democrat Terrell McSweeny. McSweeny has said that she would step down on Friday.