TY - JOUR
T1 - Releasing the brakes of tumor immunity with anti-PD-L1 and pushing its accelerator with L19-IL2 cures poorly immunogenic tumors when combined with radiotherapy
AU - Olivo Pimentel, Veronica
AU - Marcus, Damiënne
AU - van der Wiel, Alexander Ma
AU - Lieuwes, Natasja G
AU - Biemans, Rianne
AU - Lieverse, Relinde Iy
AU - Neri, Dario
AU - Theys, Jan
AU - Yaromina, Ala
AU - Dubois, Ludwig J
AU - Lambin, Philippe
N1 - © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY. Published by BMJ.
PY - 2021/3
Y1 - 2021/3
N2 - Background Poorly immunogenic tumors are hardly responsive to immunotherapies such as immune checkpoint blockade (ICB) and are, therefore, a therapeutic challenge. Combination with other immunotherapies and/or immunogenic therapies, such as radiotherapy (RT), could make these tumors more immune responsive. We have previously shown that the immunocytokine L19-IL2 combined with single-dose RT resulted in 75% tumor remission and a 20% curative abscopal effect in the T cell-inflamed C51 colon carcinoma model. This treatment schedule was associated with the upregulation of inhibitory immune checkpoint (IC) molecules on tumor-infiltrating T cells, leading to only tumor growth delay in the poorly immunogenic Lewis lung carcinoma (LLC) model. Methods We aimed to trigger curative therapeutic responses in three tumor models (LLC, C51 and CT26) by "pushing the accelerator" of tumor immunity with L19-IL2 and/or "releasing the brakes" with ICB, such as antibodies directed against cytotoxic T lymphocyte associated protein 4 (CTLA-4), programmed death 1 (PD-1) or its ligand (PD-L1), combined with single-dose RT (10 Gy or 5 Gy). Primary tumor endpoint was defined as time to reach four times the size of tumor volume at start of treatment (4TxSV). Multivariate analysis of 4TxSV was performed using the Cox proportional hazards model comparing each treatment group with controls. Causal involvement of T and natural killer (NK) cells in the anti-tumor effect was assessed by in vivo depletion of T, NK or both cell populations. Immune profiling was performed using flow cytometry on single cell suspensions from spleens, bone marrow, tumors and blood. Results Combining RT, anti-PD-L1 and L19-IL2 cured 38% of LLC tumors, which was both CD8(+) T and NK cell dependent. LLC tumors were resistant to RT +anti-PD-L1 likely explained by the upregulation of other IC molecules and increased T regulatory cell tumor infiltration. RT+L19-IL2 outperformed RT+ICB in C51 tumors; effects were comparable in CT26 tumors. Triple combinations were not superior to RT+L19-IL2 in both these models. Conclusions This study demonstrated that combinatorial strategies rationally designed on biological effects can turn immunotherapy-resistant tumors into immunologically responsive tumors. This hypothesis is currently being tested in the international multicentric randomized phase 2 trial: ImmunoSABR (NCT03705403).
AB - Background Poorly immunogenic tumors are hardly responsive to immunotherapies such as immune checkpoint blockade (ICB) and are, therefore, a therapeutic challenge. Combination with other immunotherapies and/or immunogenic therapies, such as radiotherapy (RT), could make these tumors more immune responsive. We have previously shown that the immunocytokine L19-IL2 combined with single-dose RT resulted in 75% tumor remission and a 20% curative abscopal effect in the T cell-inflamed C51 colon carcinoma model. This treatment schedule was associated with the upregulation of inhibitory immune checkpoint (IC) molecules on tumor-infiltrating T cells, leading to only tumor growth delay in the poorly immunogenic Lewis lung carcinoma (LLC) model. Methods We aimed to trigger curative therapeutic responses in three tumor models (LLC, C51 and CT26) by "pushing the accelerator" of tumor immunity with L19-IL2 and/or "releasing the brakes" with ICB, such as antibodies directed against cytotoxic T lymphocyte associated protein 4 (CTLA-4), programmed death 1 (PD-1) or its ligand (PD-L1), combined with single-dose RT (10 Gy or 5 Gy). Primary tumor endpoint was defined as time to reach four times the size of tumor volume at start of treatment (4TxSV). Multivariate analysis of 4TxSV was performed using the Cox proportional hazards model comparing each treatment group with controls. Causal involvement of T and natural killer (NK) cells in the anti-tumor effect was assessed by in vivo depletion of T, NK or both cell populations. Immune profiling was performed using flow cytometry on single cell suspensions from spleens, bone marrow, tumors and blood. Results Combining RT, anti-PD-L1 and L19-IL2 cured 38% of LLC tumors, which was both CD8(+) T and NK cell dependent. LLC tumors were resistant to RT +anti-PD-L1 likely explained by the upregulation of other IC molecules and increased T regulatory cell tumor infiltration. RT+L19-IL2 outperformed RT+ICB in C51 tumors; effects were comparable in CT26 tumors. Triple combinations were not superior to RT+L19-IL2 in both these models. Conclusions This study demonstrated that combinatorial strategies rationally designed on biological effects can turn immunotherapy-resistant tumors into immunologically responsive tumors. This hypothesis is currently being tested in the international multicentric randomized phase 2 trial: ImmunoSABR (NCT03705403).
KW - immunotherapy
KW - radiotherapy
KW - tumor microenvironment
KW - CTLA-4 BLOCKADE
KW - ANTIBODY
KW - CHECKPOINT INHIBITOR
KW - MECHANISMS
KW - ANTITUMOR-ACTIVITY
KW - COMBINATION
KW - CANCER
KW - IMMUNOCYTOKINE NHS-IL12
KW - PD-L1
KW - T-CELLS
U2 - 10.1136/jitc-2020-001764
DO - 10.1136/jitc-2020-001764
M3 - Article
C2 - 33688020
SN - 2051-1426
VL - 9
JO - Journal for ImmunoTherapy of Cancer
JF - Journal for ImmunoTherapy of Cancer
IS - 3
M1 - 001764
ER -