Cancer Immunotherapy Scores Again

The use of antibodies to block pathways inhibiting the endogenous immune response to cancer, known as checkpoint blockade therapy, has stirred up a great deal of excitement among scientists, physicians, and patients alike. Clinical trials evaluating the safety and efficacy of antibodies that block the T cell inhibitory molecules CTLA-4 and PD-1 have reported success in treating subsets of patients with metastatic melanoma and renal cell carcinoma. Antibodies targeting these pathways have been approved for clinical use, and patients once unresponsive to any sort of conventional treatment have shown good and stable clinical responses—some remaining free of disease progression for many years. What types of cancer can benefit of immunotherapy and the factors that determine whether a patient will respond to treatment are now pressing questions. In the past month, seven new studies have begun to point toward the answers.