Active specific immunotherapy with autologous tumor cell vaccines for stage II colon cancer: Logistics, efficacy, safety and immunological pharmacodynamics

In the area of cancer treatment, immunotherapy with vaccines has suffered in the last five years, due to many clinical trial failures. One must keep in mind however, that many of the clinical trials conducted in the past decade were performed without the benefit of sound regulatory guidance or validated and compliant manufacturing processes. This has clearly been the case for patient specific, tumor cell vaccine therapy. The safety concerns that emanated within the regulatory agencies from the Somatic Cell Therapy concepts, translated to active specific immunotherapy with vaccines. Fortunately, in the past five years advances in understanding the immune system, improved design of clinical trials, improvement and compliance of manufacturing processes provided opportunities to significantly improve efficacy and safety. Clearly, the vaccine research establishment has learned the importance of not just selecting antigens but the requirement of tumor associated immunogens that can stimulate a functional immune response. Also, it has become clear that immunotherapy works best in situations of minimal residual disease. Finally, more realistic endpoints in clinical trials have been recognized and accepted by oversight review committees. This commentary describes the "trials and tribulations" of developing a patient specific, autologous tumor cell vaccine for therapy of Stage II colon cancer.