Finally, the therapeutic performance of Adcitmer and its aglycosylated form was assessed in an MCC xenograft mouse model.Investigating the Adcitmer interaction with immune cells demonstrated that it is mostly mediated by Fc recognition. Accordingly, Adcitmer aglycosylation led to reduced immune cell toxicity and strikingly also to improved therapeutic performance even in an MCC xenograft model using immunodeficient mice.Our study suggests that aglycosylated Adcitmer should be considered as a therapeutic option in patients with advanced MCC or other CD56-positive tumors.