Does development of iraes suggest improved cancer treatment outcomes compared with nondevelopment of IRAEs?
Some data suggest that the occurrence of an IRAE predicts a better cancer response to ICPI treatment. The hypothesis is that the occurrence of an IRAE reflects better activation of the immune system. A meta-analysis with nivolumab in the treatment of melanoma showed a slightly better response rate (44%) in those who required immune-modulating agents to treat IRAEs compared with those who did not receive immune-modulating agents (36%). Another study with ipilimumab in patients with melanoma showed that an early IRAE predicted a better probability of an objective antitumor response; furthermore, all patients who achieved a complete response had more severe IRAEs. In patients treated with pembrolizumab for melanoma, the occurrence of vitiligo was also a predictor of an objective response. Patients who developed early IRAEs while being treated for NSCLC with nivolumab also showed a better objective response (37% versus 17%) and had longer progression-free survival (6.4 months versus 1.5 months). Further studies looking at the exact nature and mechanism of this relationship are needed.