The Efficacy of Immune Checkpoint Inhibitors

Roy S. Herbst, MD, PhD, a professor of Medicine at Yale Cancer Center and chief of Medical Oncology at Smilow Cancer Hospital at Yale-New Haven in Connecticut, describes immunotherapy as one of the most exciting advances in cancer care.

There is a need to target both the tumor and the microenvironment. Realistically, Herbst notes, 70% or more of patients may not have an actionable mutation for which they can receive an oral targeted agent. However, many of these patients may benefit from an antibody against PD-1 or PD-L1, both of which are important regulators of the immune checkpoint.

Many tumors are immunogenic and can be killed by T cells. However, these tumors express PD-L1, which makes them invisible to the immune system. Now, with modern immunotherapies, it is becoming increasingly possible to interact and break up that invisibility. As an example, Herbst notes, the antibody MPDL3280A that targets PD-L1 produced promising results with both high and durable responses.

Clinical Pearls

The next step for research is to determine if immunotherapies should be used alone or in combinations.

• Herbst believes that immunotherapies are one of the most exciting advances in cancer care
• Tumors express PD-L1, which makes them invisible to the immune system
• Checkpoint inhibitors that target PD-1 and PD-L1 remove this invisibility
• The next step for research is to determine if immunotherapies should be used alone or in combinations