PD-1 failure → TIL therapy

This sequence pairing follows failure of Immune checkpoint inhibitors with TIL therapy in Melanoma: when checkpoint blockade fails, harvesting and expanding the patient's own tumour-reactive T cells can still produce responses. The rationale is that checkpoint failure often reflects too few tumour-reactive T cells rather than none, and TIL therapy multiplies them a thousand-fold, supplying cells that were quantitatively insufficient rather than absent. Lifileucel received accelerated approval for use after anti-PD-1 therapy such as Pembrolizumab, and long-term durability data support the approach. The pairing is reached from the Melanoma entry and illustrates how a cell therapy can rescue a setting where antibodies have stopped working.