An antibody drug conjugate (ADC) composed of SP8166 (H01), an anti-folate receptor alpha (FolRa; FOLR1) human immunoglobulin G1 (IgG1) antibody, conjugated to a proprietary cleavable drug linker, SC239, containing a tubulin-targeting 3-aminophenyl hemiasterlin warhead, SC209, with potential antineoplastic activity. Upon intravenous administration, the SP8166 antibody moiety targets and binds to FolRa expressed on certain tumor cells. Upon binding, internalization, and enzymatic cleavage, the cytotoxic SC209 moiety induces tumor cell death in FolRa-expressing cells. FolRa is a glycosylphosphatidylinositol linked cell-surface glycoprotein that is widely expressed in certain cancers including serous and epithelial ovarian cancer, endometrial adenocarcinoma, non-small cell lung cancer and triple negative breast cancer. In contrast, FolRa expression is limited in normal tissues.