JAMA Oncol. https://doi.org/10.1001/jamaoncol.2019.1022 (2019)

Immune checkpoint blockade for cancer therapy can result in severe immune-related adverse events, and restarting this therapy after cessation can induce similar events, but the risk–reward ratio suggests that it is worth the risk.

Immune checkpoint blockade is based on reactivating a patient’s immune system to target their tumor. This can lead to severe adverse immune events as a result of immune system activation. While most of these events resolve after they arise, it is unknown if it is safe to readminister immune checkpoint blockade after therapy is stopped.

In a clinical trial in France, 93 participants who had previously received immune checkpoint blockade and experienced one of these events restarted the therapy. While the same adverse event, or a different one, occurred in 22 patients, the trial indicates that the risk–reward ratio is acceptable if patients are closely monitored.