Pneumotoxicity associated with immune checkpoint inhibitor therapies

Immune checkpoint inhibitor therapies represent a new paradigm in cancer therapeutics, in which the targets are not the cancer cells, but the body's own immune system. Harnessing the immune system to better fight cancer has generated a unique spectrum of immune-related adverse events (IrAEs) that effect virtually every major organ system. Although lung involvement is less common than other forms of IrAEs, its consequences are potentially lethal. This review focuses on the evolving spectrum of lung toxicities associated with the two major classes of immune checkpoint inhibitor therapies, cytotoxic T-cell ligand-4, and programed cell death-1 (PDL-1).

Lung injury was not reported in the earliest clinical trials of immune checkpoint inhibitors. More recent studies, however, have described unique radiographic and clinical toxicity profiles that differ significantly from lung injury patterns associated with conventional cytotoxic therapies. The pathophysiologic mechanisms of immune-related lung injury, its radiographic and clinical disease spectrum, associated risk factors, and optimal treatment strategies remain poorly understood.

Adverse immune-mediated lung events are increasingly recognized as unique and potentially life-threatening sequelae of checkpoint inhibitor therapies. Early recognition of symptoms and radiographic abnormalities is essential to proper management and successful outcome.