An antibody-drug conjugate (ADC) composed of a humanized monoclonal antibody against human inactive tyrosine-protein kinase 7 (PTK7) linked, via a cleavable valine-citrulline linker, to an analog of the auristatin microtubule inhibitor dolastatin 10, auristatin-0101, with potential antineoplastic activity. Upon administration, cofetuzumab pelidotin targets and binds to PTK7 expressed on tumor cells. Upon binding, internalization and cleavage, auristatin-0101 binds to tubulin and inhibits its polymerization, resulting in G2/M phase arrest and apoptosis of PTK7-expressing tumor cells. PTK7, a tumor-associated antigen (TAA), is overexpressed on a variety of cancer cells.