HARRISBURG — Val Arkoosh, a trained anesthesiologist who chairs the board of trustees for Pennsylvania’s third-most populous county, ended her campaign for the U.S. Senate on Friday.

In a video message, Arkoosh stressed the importance of a Democrat winning the Senate seat being released by retired Republican Senator Pat Toomey and said she would work to make that happen.

Arkoosh, 61, is a former chair of anesthesiology at Drexel University College of Medicine who now chairs Montgomery County’s three-member board. Arkoosh ran unsuccessfully for Congress in 2014 and previously played a prominent role in his public campaign to pass President Barack Obama’s health care bill, the Affordable Care Act.

Also in the Democratic primary race are Lt. Gov. John Fetterman, State Rep. Malcolm Kenyatta of Philadelphia and U.S. Rep. Conor Lamb of suburban Pittsburgh.

Arkoosh trailed the pack in last weekend’s approval vote at the Democratic State Committee and trailed Fetterman and Lamb in fundraising.

Still, Arkoosh had the backing of the well-funded EMILY’S List, which promotes women candidates who support abortion rights, and 314 Action, which supports scientists in public office.

The primary is May 17. The deadline for filing signatures to appear on the ballot is March 8.