Monoclonal antibodies in the management of solid tumors

Thorough understanding of the complex interactions between components of immunological response has led to the arousal of the concept of immune-mediated anti-cancer therapy. Although, the use of monoclonal antibodies (MAbs) in hematological malignancies met with success, therapy of solid tumors has been impeded by many obstacles. Some MAbs have increased the efficacy of treatment of certain tumors with acceptable adverse events. Trastuzumab, cetuximab and bevacizumab have become FDA approved for the treatment of breast and colorectal cancer, respectively. The dosing strategies, timing and schedule of antibody administration, duration of treatment are yet to be determined under specific circumstances. Combinations with other biologic agents, such as small-molecule inhibitors of the same pathway would be really useful. Multimodality approaches are based on synergistic effects observed with the combination of antibodies with chemotherapeutic drugs and/or radiotherapy. Immune-mediated effects may be further exploited with the use of bivalent (bispecific) molecules, while radioimmunotherapy via radiolabelling of the antibody is feasible. Modified recombinant antibodies could be applied for toxin delivery to tumor cells, while molecules fused with drug-activating enzymes can mediate prodrug therapy. Increased penetrability into tumors can also be achieved with novel antibody fragments. In the future, better selection of patient subpopulations with tumors overexpressing disease-related clinical biomarkers could result in an increase in both efficacy and specificity of antibody-based treatment.