Descrição
Systemic corticosteroids such as dexamethasone can attenuate pembrolizumab's immune-stimulating anti-tumour activity by suppressing the immune effector responses that the checkpoint inhibitor relies on.
Mecanismo
Pembrolizumab blocks PD-1 on T cells, enhancing T-cell-mediated tumour killing; dexamethasone broadly suppresses T-cell activation, cytokine production, and effector function, potentially counteracting pembrolizumab's mechanism.
Significância Clínica
Retrospective analyses suggest that baseline corticosteroid use is associated with reduced objective response rates and progression-free survival in patients receiving anti-PD-1 therapy; the effect appears dose-dependent (>10 mg prednisone equivalent).
Conduta
Use the lowest effective corticosteroid dose for the shortest duration when pembrolizumab is prescribed; reserve dexamethasone for irAE management using standard protocols; document the indication clearly.