The present invention concerns the biotechnology sector and more specifically human healthcare. In particular, the present invention describes a vaccine composition for therapeutic use thereof on cancer patients. The vaccine composition described in the present invention has as active principle a chemical conjugate of human recombining Epidermic Growth Factor (hrEGF) and are combining protein P64k. In addition, specific conditions are described for performing a conjugation reaction which produces said chemical conjugate in a controlled and reproducible manner. In another embodiment, the present invention concerns a method for purification of the chemical conjugate which not only provides greater purity for the therapeutic composition, but surprisingly increases the immunogenic activity causing significant increases in the anti-EGF antibody titers in humans. In addition, the present invention provides the methodology for producing a vaccine preparation with more than one type of dose presentation (total milligrams of conjugates/vial). This versatility in the presentation of the vaccine preparation enables the immunization dose per patient to be increased, but without involving an increase in immunization frequency and/or the number of immunization sites. The present invention involves a healthcare method for producing the vaccine for cancer therapy, administered by parenteral means.