What is cofetuzumab biosimilar research grade? Cofetuzumab is a humanized IgG1-kappa monoclonal antibody against PTK7, which is a tumor-associated antigen (TAA) and overexpressed on a variety of cancer cells. Cofetuzumab pelidotin is an antibody-drug conjugate (ADC) composed of cofetuzumab 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. Cofetuzumab biosimilar uses the same protein sequences as the therapeutic antibody cofetuzumab.