Five Black House Democrats are endorsing Democrat Angela Alsobrooks in her Maryland Senate bid, days after her primary opponent apologized for using a racial slur in a House hearing.

Why it matters: The five lawmakers bucked their House colleague Rep. David Trone (D-Md.), Alsobrooks' primary opponent, in endorsing the Prince George's County executive, Axios has learned.

• Trone used a racial slur in a House hearing last week. He apologized on Friday, saying he meant to use the word "bugaboo."
• Trone is considered the front-runner in the Democratic primary. Trone and Alsobrooks are seeking to face Republican Gov. Larry Hogan, a popular former Maryland governor, for the Senate seat in November.
• Reps. Barbara Lee (D-Calif.), Gregory Meeks (D-N.Y.), Joyce Beatty (D-Ohio), Yvette Clarke (D-N.Y.) and Jasmine Crockett (D-Texas) endorsed Alsobrooks.

The big picture: The Democratic primary in the state has been one of the most expensive in the country.

• Over $29 million has already been spent in the race, according to AdImpact Politics. That makes it the third most expensive primary in the country, with Trone, a wealthy businessman, accounting for 97% of that spending.
• Hogan leads Alsobrooks and Trone in hypothetical general election matchups, according to a Washington Post-University of Maryland poll.

What they're saying: Lee said Alsobrooks is a voice "sorely missing in the Senate."

• "Her vision and integrity make her the best choice to represent Maryland in the Senate," Clarke said.
• "The enthusiasm and support behind our grassroots campaign is growing as we continue our fight for Marylanders across the state," Alsobrooks said of the endorsements.