Mirco J. Friedrich

Background: Chimeric antigen receptor (CAR) T-cell therapy has demonstrated significant benefits in the treatment of relapsed/refractory multiple myeloma (RRMM). However, these outcomes can be compromised by severe complications, including cytokine release syndrome, immune effector cell-associated neurotoxicity syndrome (ICANS) and immune effector cell-associated hematotoxicity (ICAHT), predisposing for life-threatening infections. Methods: This retrospective observational study examined a total of 129 patients with RRMM who had received idecabtagene vicleucel (ide-cel) at two major myeloma centers in Germany and one center in the USA to assess the Endothelial Activation and Stress Index (EASIX) as a risk marker for an unfavorable clinical course and outcome after CAR T-cell therapy. EASIX is calculated by lactate dehydrogenase (U/L) × creatinine (mg/dL) / platelets (10⁹ cells/L) and was determined before lymphodepletion (baseline) and at the day of CAR T-cell infusion (day 0). The analysis was extended to EASIX derivatives and the CAR-HEMATOTOX score. Results: An elevated baseline EASIX (>median) was identified as a risk marker for severe late ICAHT, manifesting with an impaired hematopoietic reconstitution and pronounced cytopenias during the late post-CAR-T period. Patients with high EASIX levels (>upper quartile) were particularly at risk, as evidenced by an increased rate of an aplastic phenotype of neutrophil recovery, severe late-onset infections and ICANS. Finally, we found associations between baseline EASIX and an inferior progression-free and overall survival. Moreover, the EASIX at day 0 also demonstrated potential to serve as a risk marker for post-CAR-T complications and adverse outcomes. Conclusions: In conclusion, EASIX aids in risk stratification at clinically relevant time points prior to CAR T-cell therapy with ide-cel. Increased EASIX levels might help clinicians to identify vulnerable patients to adapt peri-CAR-T management at an early stage.

Open-access immunosequencing data | Friedrich, Mirco Julian | Cancer Cell | Adaptive Biotechnologies | Adaptive immunotherapy including bispecific T cell engagers (TCE) has shown promise in the treatment of various cancers, but clinical responses are heterogeneous and often not durable. As response to TCE is suggested to be independent of tumor recognition and T cell state, molecular determinants or mediators of primary and acquired resistance towards TCE remain poorly understood. Here, we identify conserved behaviors of bone marrow residing CD4+ and CD8+ T cells in multiple myeloma patients undergoing TCE therapy. We show that the bone marrow immune landscape reacts to TCE therapy with cell state-dependent clonal T cell expansion and herewith infer coupling of tumor recognition via MHC-I, T cell exhaustion and clinical response. While we find the abundance of exhausted-like memory CD8+ T cell clones to be associated with clinical response failure, we describe loss of target epitope and MHC class I expression as tumor-intrinsic mechanisms of acquired resistance to TCE.