Immunomodulation therapy in colorectal carcinoma

There has been much progress in the understanding of the relationship between the immune system and colorectal cancer. This has led to the use of immunomodulatory therapy in the adjuvant and palliative treatment of the condition. Although attempts at the use of non-specific immunomodulation with agents such as levamisole, cimetidine, alpha interferon and Bacillus Calmette-Guerin (BCG) have not produced significant clinical benefits when tested in randomized trials in both the adjuvant setting and for metastatic disease, promising results are being obtained with more specific therapy. Edrocolomab, a murine monoclonal antibody targeting the 17-1A antigen on malignant colorectal cells has produced a reduction in relapse and mortality rates when used as adjuvant treatment following surgery for Dukes’ C colon cancer. Active specific therapy with autologous tumour vaccine administered with BCG has produced similar benefits in Dukes’ B cancer. Both 3H1 anti-idiotypic antibody against carcinoembryonic antigen and 105AD7 antibody to gp72 glycoprotein have demonstrated in-vitro and in-vivo immune activation against tumour. Non-randomized studies postulate prolongation of survival using these antibodies in advanced disease. These agents are all currently being tested in randomized studies powered to detect meaningful survival differences and clinical benefit. Immune therapy offers the potential of low toxicity therapy in colorectal cancer and may have a role as an adjunct to conventional chemotherapy.