MabVax Therapeutics Holdings, Inc. is a clinical-stage biopharmaceutical company. The Company is engaged in the discovery, development and commercialization of human monoclonal antibody products and vaccines for the diagnosis and treatment of a variety of cancers. The Company has discovered a pipeline of human monoclonal antibody products based on the protective immune responses generated by patients who have been immunized against targeted cancers. The Company's lead antibody candidate, 5B1, is being developed as a therapeutic product and as a diagnostic imaging product. The antibody targets carbohydrate antigen sialyl Lewisa (sLea), which is expressed on tumors of the gastrointestinal tract, including pancreatic, colon and stomach cancers, as well as ovarian, breast and small cell lung cancers. The Company is also developing the 5B1 antibody conjugated to a radiolabel as a positron emission tomography (PET) imaging agent to assist in the diagnosis of pancreatic cancer.