Lymphopenia combined with low TCR diversity (divpenia) predicts poor overall survival in metastatic breast cancer patients

Lymphopenia (< 1Giga/L) detected before initiation of chemotherapy is a predictive factor for death in metastatic solid tumors. Combinatorial T cell repertoire (TCR) diversity was investigated and tested either alone or in combination with lymphopenia as a prognostic factor at diagnosis for overall survival (OS) in metastatic breast cancer (MBC) patients. The combinatorial TCR diversity was measured by semi quantitative multi-N-plex PCR on blood samples before the initiation of the first line chemotherapy in a development (n = 66) and validation (n = 67) MBC patient cohorts. A prognostic score, combining lymphocyte count and TCR diversity was evaluated. Univariate and multivariate analyses of prognostic factors for OS were performed in both cohorts. Lymphopenia and severe restriction of TCR diversity called “divpenia” (diversity ≤ 33%) were independently associated with shorter OS. Lympho-divpenia combining lymphopenia and severe divpenia accurately identified patients with poor OS in both cohorts (7.6 and 10.6 vs 24.5 and 22.9 mo). In multivariate analysis including other prognostic clinical factors, lympho-divpenia was found to be an independent prognostic factor in the pooled cohort (p = 0.005) along with lack of HER2 and hormonal receptors expression (p = 0.011) and anemia (p = 0.009). Lympho-divpenia is a novel prognostic factor that will be used to improve quality of MBC patients’ medical care

Étude des distorsions du répertoire immunitaire en tant que facteur pronostique de risque chez les patientes souffrant d’un cancer du sein métastatique en 1ère rechute : étude de la valeur pronostique de la lymphopénie et de la divpénie

Previous work of the team demonstrated the major impact of lymphopenia (<1Giga/L), detected before treatment, on overall survival of patients with solid metastatic cancer, highlighting the importance of immune system in controlling tumor progression. During my thesis project, I analyzed the contribution of the combinatorial diversity of the TCR β chain, another indicator of the quality of the immune system, as a prognostic marker in patients with metastatic breast cancer. I was able to show that a score combining the diversity of TCR and the number of lymphocytes (score NDL) is an independent factor of poor prognostic in multivariate analysis. This score allows identification of a subpopulation of patients at risk who has both a lymphopenia and a low combinatorial diversity (<33%) of TCR and for which a reduction in the median survival was observed. We also made further study of the impact of subpopulations of lymphocytes and plasma cytokines. In parallel, I developed molecular tests to improve the study of TCR repertoire diversity at the genomic level. This work opens the door to new therapeutic strategies that would consider immune system dysfunctions. Indeed, following these results, a clinical trial based on the administration of IL-7 cytokine for the expansion of T cells before or during chemotherapy has been activated at the Centre Léon BérardDes travaux antérieurs de l’équipe ont démontré l’impact majeur de la lymphopénie (<1Giga/L), détectée avant tout traitement, sur la survie globale des patients atteints d’un cancer solide en phase métastatique, soulignant ainsi l’importance du système immunitaire dans le contrôle de la progression tumorale. Au cours de mon projet de thèse, j’ai analysé l’apport de la diversité combinatoire de la chaine β du TCR, autre indicateur de la qualité du système immunitaire, en tant que marqueur pronostique chez des patientes atteintes de cancer du sein en phase métastatique. J’ai pu montrer qu’un score combinant la diversité des TCR et le nombre de lymphocytes (score NDL) est un facteur indépendant de mauvais pronostic en analyse multivariée. Ce score permet l’identification d’une sous population de patientes à risque qui présente à la fois une lymphopénie et une faible diversité (< 33%) combinatoire du TCR et pour laquelle une très forte réduction de la médiane de survie est observée. Nous avons également réalisé une étude plus approfondie de l’impact des sous-populations de lymphocytes et des cytokines plasmatiques produites. En parallèle, j’ai été amené à développer des tests de biologie moléculaire pour améliorer l’étude de la diversité du répertoire des TCR au niveau génomique. Ces travaux nous ouvrent la voie vers de nouvelles stratégies thérapeutiques qui intégreraient les perturbations du système immunitaire. En effet, suite à ces résultats, un essai clinique basé sur l’administration d’IL-7, cytokine permettant l’expansion des cellules T avant ou pendant la chimiothérapie vient d’être activé au Centre Léon Bérar

Study of distortions of the immune repertoire as a prognostic factor of risk in patients suffering from metastatic breast cancer in first relapse : study of the prognostic value of lymphopenia and divpenia

Des travaux antérieurs de l’équipe ont démontré l’impact majeur de la lymphopénie (<1Giga/L), détectée avant tout traitement, sur la survie globale des patients atteints d’un cancer solide en phase métastatique, soulignant ainsi l’importance du système immunitaire dans le contrôle de la progression tumorale. Au cours de mon projet de thèse, j’ai analysé l’apport de la diversité combinatoire de la chaine β du TCR, autre indicateur de la qualité du système immunitaire, en tant que marqueur pronostique chez des patientes atteintes de cancer du sein en phase métastatique. J’ai pu montrer qu’un score combinant la diversité des TCR et le nombre de lymphocytes (score NDL) est un facteur indépendant de mauvais pronostic en analyse multivariée. Ce score permet l’identification d’une sous population de patientes à risque qui présente à la fois une lymphopénie et une faible diversité (< 33%) combinatoire du TCR et pour laquelle une très forte réduction de la médiane de survie est observée. Nous avons également réalisé une étude plus approfondie de l’impact des sous-populations de lymphocytes et des cytokines plasmatiques produites. En parallèle, j’ai été amené à développer des tests de biologie moléculaire pour améliorer l’étude de la diversité du répertoire des TCR au niveau génomique. Ces travaux nous ouvrent la voie vers de nouvelles stratégies thérapeutiques qui intégreraient les perturbations du système immunitaire. En effet, suite à ces résultats, un essai clinique basé sur l’administration d’IL-7, cytokine permettant l’expansion des cellules T avant ou pendant la chimiothérapie vient d’être activé au Centre Léon BérardPrevious work of the team demonstrated the major impact of lymphopenia (<1Giga/L), detected before treatment, on overall survival of patients with solid metastatic cancer, highlighting the importance of immune system in controlling tumor progression. During my thesis project, I analyzed the contribution of the combinatorial diversity of the TCR β chain, another indicator of the quality of the immune system, as a prognostic marker in patients with metastatic breast cancer. I was able to show that a score combining the diversity of TCR and the number of lymphocytes (score NDL) is an independent factor of poor prognostic in multivariate analysis. This score allows identification of a subpopulation of patients at risk who has both a lymphopenia and a low combinatorial diversity (<33%) of TCR and for which a reduction in the median survival was observed. We also made further study of the impact of subpopulations of lymphocytes and plasma cytokines. In parallel, I developed molecular tests to improve the study of TCR repertoire diversity at the genomic level. This work opens the door to new therapeutic strategies that would consider immune system dysfunctions. Indeed, following these results, a clinical trial based on the administration of IL-7 cytokine for the expansion of T cells before or during chemotherapy has been activated at the Centre Léon Bérar

T‐cell receptor diversity as a prognostic biomarker in melanoma patients

International audienc

Peripheral blood TCR repertoire profiling may facilitate patient stratification for immunotherapy against melanoma

Many metastatic melanoma patients experience durable responses to anti-PD1 and/or anti-CTLA4, however, a significant proportion (over 50%) do not benefit from the therapies. In this study, we sought to assess pretreatment liquid biopsies for biomarkers that may correlate with response to checkpoint blockade. We measured the combinatorial diversity evenness of the T-cell receptor (TCR) repertoire (the DE50, with low values corresponding to more clonality and lack of TCR diversity) in pretreatment liquid biopsies from melanoma patients treated with anti-CTLA4 (n = 42) or anti-PD1 (n = 38) using a multi-N-plex PCR assay on genomic DNA (gDNA). A ROC curve determined the optimal threshold for a dichotomized analysis according to objective responses as defined by RECIST1.1. Correlations between treatment outcome, clinical variables, and DE50 were assessed in multivariate regression models and confirmed with Fisher exact tests. In samples obtained prior to treatment initiation, we showed that low DE50 values were predictive of a longer progression-free survival and good responses to PD-1 blockade, but on the other hand predicted a poor responses to CTLA4 inhibition. Multivariate logistic regression models identified DE50 as the only independent predictive factor for response to anti-CTLA4 therapy (P = 0.03) and anti-PD1 therapy (P = 0.001). Fisher exact tests confirmed the association of low DE50 with response in the anti-CTLA4 (P = 0.041) and the anti-PD1 cohort (P = 0.0016). Thus, the evaluation of basal TCR repertoire diversity in peripheral blood, using a PCR-based method, could help predict responses to anti-PD1 and anti-CTLA4 therapies