The present disclosure provides a low pH pharmaceutical composition comprising (a) an antibody constructs comprising a first domain binding to a target cell surface antigen, a second domain binding to a second antigen and preferably a third domain, which is a specific Fc modality, (b) at least one buffer agent, (c) at least one saccharide, and (d) at least one surfactant; and wherein the pH of the pharmaceutical composition is in the range of 3.5 to 6.