Immune-based therapeutics for pediatric cancer

Abstract

Importance of the field: Although most children with cancer are cured, there remain significant limitations of standard treatment, most notably chemotherapy resistance and non-specific toxicities. Novel immune-based therapies that target pediatric malignancies offer attractive adjuncts and/or alternatives to commonly employed cytotoxic regimens of chemotherapy or radiotherapy. Elucidation of the principles of tumor biology and the development of novel laboratory technologies over the last decade have led to substantial progress in bringing immunotherapies to the bedside.

Areas covered in this review: Current immunotherapeutic clinical trials in pediatric oncology and the science behind their development are reviewed.

What the reader will gain: Most of the immune-based therapies studied to date have been well tolerated, and some have shown promise in the setting of refractory or high-risk malignancies, demonstrating that immunotherapy has the potential to overcome resistance to conventional chemotherapy.

Take home message: Some immune-based therapies, such as ch14.18 and MTP-PE, have already been proven effective in phase III randomized trials. Further studies are needed to optimize and integrate other therapies into standard regimens, and to test them in randomized trials for patients with childhood cancer.

Figure 1. Components of a chimeric antigen receptor

The binding portion of the CAR consists of the Fv fragment from an antibody against a target antigen, in this case CD19. Typically a T cell receptor signaling domain is attached to the Fv fragment, in this case using a CD28/CD3ζ tail.

Figure 2. Potential mechanisms of tumor cell lysis by monoclonal antibodies

MoAbs can (1) be conjugated to toxins or radionuclides, (2) recruit effector cells to participate in ADCC or (3) release inflammatory cytokines that contribute to tumor killing, (4) activate complement, (5) interfere with growth factor signaling, or (6) bind anti-idiotype antibodies.