The pre-existing T cell landscape determines the response to bispecific T cell engagers in multiple myeloma patients

Menée à partir d'échantillons sanguins et d'échantillons de moelle osseuse provenant de personnes saines et de patients atteints d'un myélome multiple, cette étude met en évidence une corrélation entre la reconnaissance de la tumeur via le complexe majeur d'histocompatibilité de classe I, l'épuisement des lymphocytes T CD8+ et la réponse aux anticorps bispécifiques engageant les lymphocytes T

Résumé en anglais

Bispecific T cell engagers (TCEs) have shown promise in the treatment of various cancers, but the immunological mechanism and molecular determinants of primary and acquired resistance to TCEs remain poorly understood. Here, we identify conserved behaviors of bone marrow-residing T cells in multiple myeloma patients undergoing BCMAxCD3 TCE therapy. We show that the immune repertoire reacts to TCE therapy with cell state-dependent clonal expansion and find evidence supporting the coupling of tumor recognition via major histocompatibility complex class I (MHC class I), exhaustion, and clinical response. We find the abundance of exhausted-like CD8+ T cell clones to be associated with clinical response failure, and we describe loss of target epitope and MHC class I as tumor-intrinsic adaptations to TCEs. These findings advance our understanding of the in vivo mechanism of TCE treatment in humans and provide the rationale for predictive immune-monitoring and conditioning of the immune repertoire to guide future immunotherapy in hematological malignancies.