A monoclonal antibody directed against the melanosomal membrane protein gp75 (or Tyrosinase-Related Protein 1 [TRP1]) with potential immunostimulatory and antineoplastic activities. Flanvotumab targets and binds to gp75. This may lead to the induction of cytotoxic T cell immune and antibody-mediated immune responses against melanoma cells expressing gp75. gp75, a pigmentation-associated antigen, is expressed in melanosomes of human melanocytes and melanomas.