1029P - Preclinical development of TCR-modified T cell therapies against mutated KRAS

Background

Mutated KRAS remains a target of great unmet medical need, especially for mutations G12V and G12D. TCR-modified T cell (TCR-T) therapies offer a precise route, via autologous modification of patient T cells, to directly address these foundational driver events in solid tumours. We describe the preclinical development of a therapeutic TCR and corresponding IMP-ready TCR-T product for KRAS G12V in HLA-A*11:01 restriction.

Methods

Using a cell-based approach, valid epitopes in mutant KRAS/HLA combinations were assessed using mass spectrometry. Mono-allelic engineered antigen-presenting cells (eAPCs) and multimer reagents were used to isolate pools of candidate TCRs from multiple naïve donor CD8 cells. TCR sensitivity and specificity were screened using eAPCs and orthogonal cancer cell lines in contact assays using engineered TCR-presenting cells (eTPCs) with TCR signalling-linked reporters. TCRs were characterized for cross-reactivity and allo-reactivity liability by screening libraries of epitope-variant eAPCs and HLA-specific eAPCs, respectively. Primary effector cells were created with a GMP-identical process. Donor CD8 cells were gene-edited, recovered with a selection marker, and expanded. Effector cells were tested both in vitro and in vivo.

Results

A selective TCR for HLA-A*11 & KRAS-G12V 10mer (VVVGAVGVGK) was isolated from 102 initial candidates using HLA-matched donors. Potential cross-reactivity was assessed with 200 eAPCs encoding saturating point mutations across the target peptide sequence. No cross-reactivity was observed with eAPCs encoding minigenes of all implied genomically-encoded peptides. Allo-reactivity was assessed with a panel of 86 common HLA mono-allelic eAPC lines, without detecting any liability. Gene-edited TCR-T exerted specific and potent TCR-mediated cytotoxicity towards multiple cancer cell lines with a range of G12V expression levels and HLA densities. A single infusion of TCR-T effector cells resulted in rapid and sustained clearance of tumour burden in NSG mice engrafted with cancer cells expressing G12V-A*11.

Conclusions

This TCR-T is being progressed into planned clinical trials. Additional TCRs for additional mutKRAS/HLA combinations are in development.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Anocca AB.

Funding

Anocca AB.

Disclosure

H. Salter: Financial Interests, Institutional, Full or part-time Employment: Anocca; Financial Interests, Institutional, Stocks/Shares: Anocca. L. Pase, R. Hill, R. Jarvis: Financial Interests, Institutional, Full or part-time Employment: Anocca; Financial Interests, Personal, Stocks/Shares: Anocca. A. Brass, D. Casarrubea, S. Virding Cullerton, J. Dunst, S. Horta, M. Masia-Balague, J. Lange, T. Parrot, A. Totomi, H. Uchtenhagen, S. Wang: Financial Interests, Institutional, Full or part-time Employment: Anocca. Z. Bashir: Financial Interests, Institutional, Financially compensated role: Anocca.