Sen. Bill Cassidy, a Louisiana Republican, has lost his bid for a third term in a remarkable defeat, after two primary challengers — including one backed by President Donald Trump — finished ahead of him in Saturday’s primary and headed to a runoff for his seat.

Rep. Julia Letlow will compete in a Republican Senate primary runoff in Louisiana, NBC News projects.

Rep. Julia Letlow (R-La.) and State Treasurer John Fleming (R) both defeated Sen. Cassidy, and will advance to that June 27 runoff.

Rep. Julia Letlow, who was backed by President Trump in the primary against incumbent Sen. Bill Cassidy, has advanced to a runoff in the Louisiana Republican primary for Senate.

Republican Sen. Bill Cassidy of Louisiana is fighting for his political life in Saturday's primary against a challenger who has been endorsed by President Donald Trump.

Key health lawmaker Sen. Bill Cassidy will lose his seat, as Louisiana’s Senate primary heads for a runoff between state treasurer John Fleming and Trump-backed Rep. Julia Letlow.

Sen. Bill Cassidy’s political career is at stake on Saturday as Louisiana voters weigh in on the Republican for the first time since he voted to convict President Donald Trump in his 2021 impeachment