We report efficacy for response-evaluable pts (REP) with RET+ MTC and safety for all pts who initiated pralsetinib...In 79 REP with RET+ MTC (mutation: 61% M918T, 28% C634X, 4% V804X, 8% other), ORR was 65% (95% CI 53–75; n=51/79, 5% complete response [CR]; 59% partial response [PR; 1 pending confirmation]).Pralsetinib demonstrated potent and durable clinical activity in RET+ MTC.