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] - The trial indicates that patients with lower disease burden are more likely to benefit from MP0533, with 6 of 8 responders presenting with less than 20% bone marrow blasts at baseline [4][7] Group 2: Expert Commentary - Prof. Courtney DiNardo expressed optimism about the clinical benefits of MP0533 in a mutation-agnostic manner for R/R AML patients, particularly those with lower disease burden [3] - Philippe Legenne highlighted the progress of the trial, noting the feasibility of the densified dosing regimen and the interest from consortia for further studies [5] Group 3: Mechanism of Action - 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] Group 4: Presentation Details - The poster presentation titled "Phase 1/2 study of MP0533" outlines clinical benefits with an acceptable safety profile across 9 dosing regimens, emphasizing the feasibility of accelerated step-up dosing [7][8]