The development of immunotherapy in older adults: New treatments, new toxicities?

Monoclonal antibodies targeting immune checkpoint molecules CTLA-4, PD-1 or PD-L1 are emerging as promising anticancer therapeutics in multiple cancer subtypes resulting in remarkable and long-lasting clinical responses. These immune checkpoint blockers (ICBs) have already obtained approval for the treatment of patients with metastatic melanoma, advanced/refractory non-small cell lung cancer and renal cell cancer. ICBs enhance immune responses against cancer cells but can also lead to inflammatory side effects called immune-related adverse events (irAEs). Such toxicities are distinct from those associated with traditional chemotherapeutic agents or molecularly targeted therapies. Although severe irAEs remain rare (~ 10% of cases under monotherapy), they can become life-threatening if not anticipated and managed appropriately. As malignancies are frequently diagnosed in older patients, ICB treatment of elderly presents a unique challenge. However, the knowledge about efficacy and toxicity of these molecules in this specific population is limited, as most of the studies have involved a low number of older patients. In this review, we will discuss about the different ICB efficacy data available for older patients. We will then highlight the specific spectrum of immunotherapy toxicities and talk about their management in the context of older adults.