Tumour-infiltrating lymphocytes (TILs)
Immune cells that have got inside the tumour. More of them means better outcomes in triple-negative breast cancer.
Stromal TILs scored on H&E (International TILs Working Group). In TNBC, each 10% increase reduces recurrence risk; stage I tumours with TILs ≥50% have >90% 5-year survival without chemotherapy, driving de-escalation trials. Also the raw material for TIL therapy.
This trial supplied the randomised proof that was missing for TIL therapy and showed academic centres can run cell-therapy phase 3 trials without industry. It supports TIL as a standard option after checkpoint inhibitor failure in melanoma and underpinned reimbursement in the Netherlands. The comparator, ipilimumab, is itself only modestly effective in this setting, and overall survival did not differ significantly.
Lifileucel proved that Steven Rosenberg's decades-old TIL concept could be industrialised into a licensed product and gave patients with checkpoint-refractory melanoma, who otherwise have few options, a chance of durable remission. It is the first cell therapy approved for any solid tumour. The treatment requires surgery to harvest tumour, hospitalisation for lymphodepletion and IL-2, and specialised centres, so its reach is limited.