Table 1.
Characterization of IHC assays used for PD-L1 assessment in different clinical trials.
| PD-L1 clone(species) | Company(platform) | Tested ICI(target) | Trial(no. of patients) | Cell type for PD-L1 scoring | Percentage of PD-L1 positive cells(cut-offs) | Indication |
|---|---|---|---|---|---|---|
| 22C3 (Mouse) |
Dako (Autostainer Link 48) |
Pembrolizumab (PD-1) |
KEYNOTE-001 (12) (495) KEYNOTE-010 (9) (1,034) KEYNOTE-024 (10) (305) KEYNOTE-021 (11) (123) |
Tumor cells | TC < 1% TC ⩾ 1%, TC ⩾ 50% (min. of 100 TC) |
Second-line (⩾1% of TC) First-line (⩾ 50% of TC) |
| 28-8 (Rabbit) |
Dako (Autostainer Link 48) |
Nivolumab (PD-1) |
Checkmate-017 (5) (272) Checkmate-057 (8) (582) Checkmate-026 (6) (541) |
Tumor cells | TC < 1% TC ⩾ 1% TC ⩾ 5% TC ⩾ 10% (min. of 100 TC) |
Second-line regardless of PD-L1 expression |
| SP142 (Rabbit) |
Ventana (BenchMark ULTRA) |
Atezolizumab (PD-L1) |
OAK (14) (850) POPLAR (15) (287) |
Tumor cells, Immune cells | TC < 1% and IC < 1% TC ⩾ 1% or IC ⩾ 1% TC ⩾ 5% or IC ⩾ 5% TC ⩾ 50% or IC ⩾ 10% (min. of 50 TC with associated stroma) |
Second-line regardless of PD-L1 expression |
| SP263 (Rabbit) |
Ventana (BenchMark ULTRA) |
Durvalumab (PD-L1) |
PACIFIC (13) (149) |
Tumor cells | TC < 1% TC ⩾ 1% TC ⩾ 25% (min. of 100 TC) |
Maintenance therapy after chemoradiotherapy (≧̸1% of TC) |
| 73-10 (Rabbit) |
Dako (Autostainer Link 48) |
Avelumab (PD-L1) |
JAVELIN (17) (184) |
Tumor cells, Immune cells |
TC < 1% TC ⩾ 1% (min. no of cells not defined) |
Not approved |
ICI, immunological checkpoint inhibitor; TC, tumor cells; IC, immune cells.