An antibody drug conjugate (ADC) composed of farletuzumab, a humanized immunoglobulin G1 (IgG1) monoclonal antibody directed against the folate receptor alpha (FRA; FolRa; FOLR1), and conjugated, via a cathepsin B-cleavable linker, to the microtubule-targeting agent (MTA) eribulin, a derivative of the macrocyclic polyether natural product halichondrin B, with potential antineoplastic activity. Upon administration of farletuzumab ecteribulin, the farletuzumab moiety targets and binds to FRA expressed on certain tumor cells. Upon binding, internalization, and enzymatic cleavage, eribulin binds to the vinca domain of tubulin and inhibits the polymerization of tubulin and the assembly of microtubules, resulting in inhibition of mitotic spindle assembly, induction of cell cycle arrest at G2/M phase, and the induction of tumor cell death in FRA-expressing cells. FRA is a glycosylphosphatidylinositol linked cell-surface glycoprotein that is widely expressed in certain cancers while its expression is limited in normal tissues.