Strategies for the Development of More Effective Adjuvant Therapy of Melanoma: Current and Future Explorations of Antibodies, Cytokines, Vaccines, and Combinations

Abstract

Adjuvant trials have evaluated the influence of multiple agents on relapse and mortality for patients with intermediate-risk (stage IIA, American Joint Committee on Cancer staging manual, 6th ed.), high-risk (stage IIB-III), or very high-risk (stage IIIB-IV) operable melanoma. A 25% to 33% reduction of relative relapse risk with high-dose IFN-α2b therapy has been documented in stage groups overall, with survival prolongation in two of these trials. In contrast, no large cooperative group trial has ever shown a significant prolongation of survival for inoperable advanced stage IV melanoma. The basis for the failure of therapies in advanced disease may lie in differences in the immune function of patients with active metastatic stage IV disease. These observations argue for the exploration of promising new therapies in adjuvant settings. Past adjuvant studies have targeted stage IIB-III patients, focusing less on the more advanced but resectable stage IIIB and IV (M_1a-b) disease groups. Current chemobiotherapy (S0008) and granulocyte-macrophage colony-stimulating factor plus peptide vaccination (E4697) trials have now evaluated the higher-risk disease groups where trials may soon be expected to yield results. Predictive markers that would allow us to focus treatment on those patients who are most likely to respond would accelerate our development of adjuvant therapy for melanoma. We have recently developed a neoadjuvant approach to high-dose IFN in which the molecular and immunologic effects of IFN have been correlated with clinical antitumor effects of this therapy. In addition, the Hellenic Oncology group has shown that the benefit of high-dose IFN is closely correlated with serologic and clinical manifestations of autoimmunity. These new insights will allow us to develop more efficient approaches to adjuvant therapy of melanoma, focusing on autoimmunity and antitumor immunity with new immunomodulators, such as anti-CTLA4 antibodies and vaccination.