CytomX Therapeutics Inc. CytomX Therapeutics Inc a clinical-stage, oncology-focused biopharmaceutical company developing novel, masked, conditionally activated biologics designed to be localized to the tumor microenvironment. It is engaged in developing antibody therapeutics based on probody technology platforms. The company's probody technology platform creates proprietary cancer immunotherapies against clinically-validated targets and develops cancer therapeutics. Probody therapeutics are designed to take advantage of conditions in the tumor microenvironment to enhance the tumor-targeting features of an antibody and reduce drug activity in healthy tissues.