Anti-CD19 CAR T-cells(KK Women's and Children's Hospital)

Relapsed/refractory multiple myeloma patients with extramedullary disease (EMD) have unfavorable prognosis and lack effective therapy. Chimeric antigen receptor (CAR) T‐cell activities in EMD have yet to be determined; how EMD‐specific microenvironment influences the clinical outcomes of CAR T‐cell therapy remains of great interest. In this prospective cohort study, patients with histologically confirmed extra‐osseous EMD were enrolled and treated with combined anti‐BCMA and anti‐CD19 CAR T‐cell therapy from May 2017 to September 2023. Thirty‐one patients were included in the study. Overall response occurred in 90.3% of medullary disease and 64.5% of EMD (p = .031). Discrepancies in treatment response were noted between medullary and extramedullary diseases, with EMD exhibiting suboptimal and delayed response, as well as shortened response duration. With a median follow‐up of 25.3 months, the median progression‐free and overall survival were 5.0 and 9.7 months, respectively. Landmark analysis demonstrated that progression within 6 months post‐infusion is strongly associated with an increased risk of death (HR = 4.58; p = .029). Compared with non‐EMD patients, patients with EMD showed inferior survival outcomes. Unique CAR‐associated local toxicities at EMD were seen in 22.6% patients and correlated with the occurrence and severity of systemic cytokine release syndrome. To the cutoff date, 65% treated patients experienced EMD progression, primarily in the form of BCMA+ progression. The pretherapy EMD immunosuppressive microenvironment, characterized by infiltration of exhausted CD8+ T cells, was associated with inferior clinical outcomes. CAR T cells have therapeutic activity in relapsed/refractory EMD, but the long‐term survival benefits may be limited. EMD‐specific microenvironment potentially impacts treatment. Further efforts are needed to extend EMD remission and improve long‐term outcomes.

Chimeric antigen receptor (CAR) T-cell therapy has improved the historically poor outcomes for relapsed and refractory (R/R) large B-cell non-Hodgkin's lymphoma (LBCL). However, nearly 60% of patients will either fail to respond or relapse after CAR T-cell therapy. Currently, PET/CT scans are used to assess response. Cell-free circulating tumor DNA (ctDNA) is released by tumor cells into the peripheral blood and can be measured for minimal residual disease (MRD) assessment.

In this retrospective, IRB approved pilot study, archived lymphoma tissue and ctDNA from peripheral blood samples on day 0, 14, 28, 56, 90, 180, and 365 after CAR T-cell infusion from 10 patients with R/R NHL were collected for next-generation sequencing (NGS) of clonal variable-diversity-joining (VDJ) rearrangements (Adaptive biotechnologies [Seattle, WA]). Response was assessed by PET/CT on days 90 and 365 and graded according to the Lugano 2014 criteria. The primary endpoint was to determine the feasibility of detecting ctDNA to monitor disease response after anti-CD19 CAR T-cell therapy. The secondary endpoint was to compare the sensitivity/specificity of MRD assessment from ctDNA to PET/CT imaging.

Nine out of 10 patients with a trackable sequence [median age 69 (range: 56-76); 55.6% male; median LDH 224], were included in this study. Each received tisagenlecleucel (tisa-cel) CAR T-cell therapy after median 2 prior treatments (range: 2-4). 7/9 patients had R/R diffuse large B-cell lymphoma (DLBCL), and 2/9 had transformed follicular lymphoma. At a median follow up of 12.7 months (range: 1.5-30 months), 4 patients were alive. By day 90, 3 patients (33.3%) achieved a radiographic complete response (CR) whilst 6 patients (66.6%) had progressive disease (PD). Detectable MRD on day 14 or day 28 had 83% sensitivity and 100% specificity for radiographic progression at any time before 1 year. For patients with PD, the median (interquartile range) MRD at day 0, 14, and 28 were 17.31 (1.01, 96.84), 9.12 (0.30, 18.8), and 23.77 (8.01, 137.53) copies per milliliter (mL), respectively. For patients with detectable MRD at day 28, mOS and mPFS were 6.7 and 1.3 months, respectively.

Monitoring MRD was a sensitive and specific method to detect poor response to tisa-cel. Additional studies evaluating MRD more frequently and with different products are warranted.