4P - CBL-B inhibition overcomes PD-1/LAG-3 mediated resistance in lung cancer

Background

A significant number of cancer patients do not benefit from PD-L1/PD-1 blockade immunotherapies. PD-1 and LAG-3 co-upregulation in T-cells is one of the major mechanisms of resistance by establishing a highly dysfunctional state in T-cells.

Methods

PD-1/LAG-3 gene co-expression signatures were extracted from a high-throughput multiomic screening associated to T-cell functions in more than 12000 TCGA cancer patients’ data. Then, PD-1 and LAG-3 signaling pathways were co-activated in T-cells and analyzed through quantitative differential high-throughput proteomics. These results were validated by conventional molecular techniques in T-cell lines, in primary T cells from NSCLC patients and in a mice lung cancer model refractory to immunotherapy.

Results

A strong PD-1/LAG-3 dysfunctional signature was found which regulated immune, metabolic, genetic, and epigenetic pathways, but especially a reinforced negative regulation of the TCR signalosome. CBL E3 ubiquitin ligases were found as key target associated to the regulation of central T-cell PD-1/LAG-3 dysfunctional pathways. Pharmacologic inhibition of CBL-B combined with PD-1/LAG-3 co-blockade demonstrated notable therapeutic efficacies in a lung cancer model refractory to immunotherapy.

Conclusions

A druggable target, CBL-B was identified by genomic and proteomic techniques in T-cells with PD-1/LAG-3 co-signaling. CBL-B inhibition combined with PD-1 and LAG-3 antibody co-blockade tripled survival in mice lung cancer model resistant to immunotherapy. These results will help identifying the mechanisms of intrinsic resistance to PD-1 blockade mediated by LAG-3 co-signaling. Patients with dysfunctional T-cell immunity resistant to conventional antibody blockade immunotherapies could benefit from immunotherapy blockade combinations with CBL-B inhibitors.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

OncoImmunology Unit, Navarrabiomed - Miguel Servet Foundation, Public University of Navarra (UPNA), University Hospital of Navarra (HUN), Health Research Institute of Navarra (IdISNA), 31008, Pamplona, Spain.

Funding

The Spanish Association against Cancer (AECC), PROYE16001ESCO; Instituto de Salud Carlos III (ISCIII)-FEDER Project grants FIS PI20/00010, FIS PI23/00196, COV20/00237, and TRANSPOCART ICI19/00069; Biomedicine Project Grant from the Department of Health of the Government of Navarre-FEDER funds (BMED 050-2019, 51-2021, 036-2023); Strategic projects from the Department of Industry, Government of Navarre (AGATA, Ref. 0011-1411-2020-000013; LINTERNA, Ref. 0011-1411-2020-000033; DESCARTHES, 0011-1411-2019-000058); European Union Horizon 2020 ISOLDA project, under grant agreement ID: 848166. L.C. is financed by Instituto de Salud Carlos III (ISCIII), co-financed by FEDER funds, "Contratos PFIS: contratos predoctorales de formación en investigación en salud"; M.E. is financed by the Navarrabiomed-Fundación Miguel Servet predoctoral contract.

Disclosure

C.J. Edwards, J. Legg: Other, Declares to be inventor of the Humabody CB213 (WO/2019/158942. 603 Crescendo Biologics Ltd.): Crescendo Biologics Ltd. D. Escors: Other, Declares to be inventor of the Humabody CB213 (WO/2019/158942. 603 Crescendo Biologics Ltd.): Navarrabiomed. All other authors have declared no conflicts of interest.