Molecular presents data from dosing cohorts of Phase 1/2a trial of MP0533

Molecular Partners presented positive initial clinical data from its ongoing Phase 1/2a trial of MP0533, a novel tetra-specific T cell engager, in a poster at the 65th American Society of Hematology Annual Meeting and Exposition. These data, which highlight initial safety and antitumor activity, expand upon those previously disclosed in the conference abstract. As of the data cut-off, 11 patients had been enrolled in the first four dosing regimens the ongoing Phase 1/2a trial of MP0533 monotherapy in patients with relapsed/refractory acute myeloid leukemia or myelodysplastic syndrome. The trial enrollment remains on track with patients currently being treated in the fifth of seven dose-escalation cohorts planned. MP0533 continues to demonstrate an acceptable safety profile across all four DRs studied. No dose-limiting toxicities were observed as of data cut-off, and all patients were able to receive their full dose of MP0533. The most frequently reported MP0533-related adverse events were infusion-related reactions and cytokine release syndrome. Two responders have been observed to date, including a patient achieving complete response in DR 4 and another patient with morphological leukemia-free state in DR 3. These responses are particularly notable for having occurred at dose levels below those predicted for therapeutically relevant activity.