Molecular Partners Presents Updated Data from Ongoing Phase 1/2a Trial of MP0533 in AML at ASH Annual Meeting

Core Insights - Molecular Partners AG is presenting updated data from a Phase 1/2a trial of its T-cell engager MP0533 for treating acute myeloid leukemia (AML) at the 67th ASH Annual Meeting [1][2] Group 1: Trial Results - The multicenter, open-label study shows that densified dosing of MP0533 is tolerable and leads to improved serum exposure with preliminary antitumor activity [2][4] - As of September 1, 2025, 54 patients have been treated with MP0533, with 8 out of 48 evaluable patients achieving a response, including 5 reaching composite complete responses [4] - Six of the eight responders had less than 20% bone marrow blasts at baseline, indicating that patients with low disease burden are likely to benefit the most from MP0533 [4][7] Group 2: Expert Commentary - Prof. Courtney DiNardo expressed optimism about the clinical benefits of MP0533 in mutation-agnostic R/R AML patients, particularly those with lower disease burden, supporting further investigation in a Phase 2 setting [3][5] Group 3: Drug Mechanism and Design - MP0533 is a novel tetra-specific T cell-engaging DARPin that targets three tumor-associated antigens (CD33, CD123, CD70) on AML cells and the immune activator CD3 on T cells, designed to preferentially kill AML cells while minimizing damage to healthy cells [6][9] Group 4: Future Development - The trial is progressing well, with the densified dosing regimen showing feasibility and an acceptable safety profile, prompting interest from several consortia for further studies in both R/R and front-line AML settings [5][9]