Atypical patterns of response to immune checkpoint inhibitors: interpreting pseudoprogression and hyperprogression in decision making for patients’ treatment

Over the last 5 years, immunotherapy has become one of the backbones for cancer treatment, showing significant improvement in prognosis for several malignancies. Currently, in clinical practice, we have several immune checkpoint inhibitors targeting cytotoxic T lymphocyte associated antigen 4 (CTLA4), programmed cell death 1 (PD-1) and programmed death ligand 1 (PD-L1), while several other drugs, directed toward different co-inhibitory or co-stimulatory molecules, are under evaluation (1).