, St. Louis attorney Ed Martin dropped out of the race.
Instead, Martin will challenge Democrat Chris Koster for state's Attorney General.
Former Republican National Committee Co-Chair Ann Wagner remains in the race along with Jotte, a Barnes-Jewish Hospital emergency room doctor from Webster Groves.
Jotte is a Harvard University medical school graduate, Fulbright Scholar at Oxford University, and spent four years working in Washington, D.C.
A statement Martin issued Thursday made no mention of the congressional bid and instead focused on Koster, a former Republican state senator who switched parties prior to his bid for attorney general in 2008.
Martin attacked Koster over his handling of state bids to oppose President Obama's healthcare reform.
Martin, feeding off his near-victory against U.S. Rep. Russ Carnahan (D-St. Louis) in 2010, had support in his bid to succeed U.S. Rep. Todd Akin (R-Wildwood.)
A statement from the Missouri Democratic Party chided Martin's switch to another contest after considering bids in other congressional districts, the U.S. Senate and the governor's race.
Wagner has lined up endorsements from national GOP figures, including Missouri's John Ashcroft, New Jersey Gov. Chris Christie and former Arkansas Gov. Mike Huckabee.
Jotte launched his campaign with limited support, but said he felt the cause was crucial.
"What's at stake is so tremendous," Jotte said. "I believe I have something to offer."
Jotte said he would bring his training and medical knowledge to Congress.
"Once I get the facts, I'll always do the right thing. I'm an independent-thinking problem-solver," he said.
The GOP primary race is considered a fait accompli for choosing a member of Congress in this new 2nd Congressional district, since it is heavily registered Republican.
Patch Editor Jean Whitney contributed to this article.