Chimeric Antigen Receptor T-Cell Therapy and Imaging Applications for Large B-Cell Lymphoma.

Chimeric antigen receptor (CAR) T-cell therapy has revolutionized the treatment of large B-cell lymphoma (LBCL) and other hematologic malignancies. Its mechanism of action relies on recent biotechnological advances that allow clinicians to harness and enhance a patient's immune system to fight cancerous cells. The indications for CAR T-cell therapy continue to expand, with ongoing trials evaluating their use in other hematologic and solid organ malignancies. This review explores the vital role of diagnostic imaging in patient selection and treatment response in CAR T-cell therapy for LBCL and the management of specific therapy-related adverse events. For a patient-centered and cost-effective use of CAR T-cell therapy, it is crucial to select patients who are likely to derive long-term benefit and optimize their care during a lengthy treatment pathway. Metabolic tumor volume and kinetics assessed at PET/CT have emerged as powerful tools to predict outcome after CAR T-cell therapy in LBCL, allowing for the early identification of lesions refractory to treatment and identification of the severity of CAR T-cell therapy toxicity. Radiologists should be aware that the success of CAR T-cell therapy is mitigated by adverse events, most importantly neurotoxicity, which remains poorly understood and challenging to treat. Neuroimaging, with experienced clinical evaluation, is critical in the diagnosis and management of neurotoxicity and the exclusion of other central nervous system complications that can occur in this clinically vulnerable patient group. This review discusses current applications of imaging in the standard CAR T-cell therapy pathway for the treatment of LBCL, which serves as a model disease in the integration of diagnostic imaging and radiomic risk markers.

A national service for delivering CD19 CAR-Tin large B-cell lymphoma - The UK real-world experience.

CD19 CAR-T have emerged as a new standard treatment for relapsed/refractory (r/r) large B-cell lymphoma (LBCL). CAR-T real-world (RW) outcomes published to date suggest significant variability across countries. We provide results of a large national cohort of patients intended to be treated with CAR-T in the UK. Consecutive patients with r/r LBCL approved for CAR-T by the National CAR-T Clinical Panel between December 2018 and November 2020 across all UK CAR-T centres were included. 404/432 patients were approved [292 axicabtagene ciloleucel (axi-cel), 112 tisagenlecleucel (tisa-cel)], 300 (74%) received the cells. 110/300 (38.3%) patients achieved complete remission (CR) at 6 months (m). The overall response rate was 77% (52% CR) for axi-cel, 57% (44% CR) for tisa-cel. The 12-month progression-free survival was 41.8% (axi-cel) and 27.4% (tisa-cel). Median overall survival for the intention-to-treat population was 10.5 m, 16.2 m for infused patients. The incidence of grade ≥3 cytokine release syndrome and neurotoxicity were 7.6%/19.6% for axi-cel and 7.9%/3.9% for tisa-cel. This prospective RW population of CAR-T eligible patients offers important insights into the clinical benefit of CD19 CAR-T in LBCL in daily practice. Our results confirm long-term efficacy in patients receiving treatment similar to the pivotal trials, but highlight the significance of early CAR-T failure.

R-GEM-Lenalidomide versus R-GEM-P as second-line treatment of diffuse large B-cell lymphoma: results of the UK NRCI phase II randomised LEGEND trial.

Outcome of patients with relapsed/refractory (r/r) diffuse large B-cell lymphoma (DLBCL) remains poor, highlighting the need for novel treatment approaches. The multicentre randomised phase II LEGEND trial evaluated lenalidomide in combination with rituximab, methylprednisolone and gemcitabine (R-GEM-L) vs. standard R-GEM-P as second-line treatment of DLBCL. The study closed early to recruitment after the planned interim analysis failed to demonstrate a complete response (CR) rate of ≥ 40% in either arm. Among 34 evaluable patients, 7/18 (38.9%) achieved CR with R-GEM-L and 3/16 (18.8%) with R-GEM-P. Median event-free and overall survival was 3.5/3.8 months and 10.8/8.3 months for R-GEM-L and R-GEM-P, respectively. The incidence of grade ≥ 3 toxicities was 52% in R-GEM-L and 83% in R-GEM-P. Efficacy and tolerability of R-GEM-L seem comparable with R-GEM-P and other standard salvage therapies, but a stringent design led to early trial closure. Combination of lenalidomide with gemcitabine-based regimens should be further evaluated in r/r DLBCL.

Downregulation of the Wnt inhibitor CXXC5 predicts a better prognosis in acute myeloid leukemia.

The gene CXXC5 on 5q31 is frequently deleted in acute myeloid leukemia (AML) with del(5q), suggesting that inactivation of CXXC5 might play a role in leukemogenesis. Here, we investigated the functional and prognostic implications of CXXC5 expression in AML. CXXC5 mRNA was downregulated in AML with MLL rearrangements, t(8;21) and GATA2 mutations. As a mechanism of CXXC5 inactivation, we found evidence for epigenetic silencing by promoter methylation. Patients with CXXC5 expression below the median level had a lower relapse rate (45% vs 59%; P = .007) and a better overall survival (OS, 46% vs 28%; P < .001) and event-free survival (EFS, 36% vs 21%; P < .001) at 5 years, independent of cytogenetic risk groups and known molecular risk factors. In gene-expression profiling, lower CXXC5 expression was associated with upregulation of cell-cycling genes and co-downregulation of genes implicated in leukemogenesis (WT1, GATA2, MLL, DNMT3B, RUNX1). Functional analyses demonstrated CXXC5 to inhibit leukemic cell proliferation and Wnt signaling and to affect the p53-dependent DNA damage response. In conclusion, our data suggest a tumor suppressor function of CXXC5 in AML. Inactivation of CXXC5 is associated with different leukemic pathways and defines an AML subgroup with better outcome.

Outcomes of Patients Treated With RCHOP With a PET-Adapted Approach for Consolidative Radiotherapy: A Retrospective Single-Center Study at the Royal Marsden Hospital.

BACKGROUND: Treatment with CHOP-based chemotherapy with consolidative radiotherapy (CRT) for primary mediastinal B cell lymphoma (PMBCL) has been the standard approach in the pre-rituximab era. Overtreatment with CRT for patients who may have already been cured by primary immunochemotherapy in the rituximab era is a significant concern due to the long-term toxicity associated with radiotherapy. Positron emission tomography (PET) may help to identify patients who may not benefit from further CRT. METHODS: We conducted a retrospective review of patients treated at the Royal Marsden Hospital between 2003 and 2020 for PMBCL to assess CRT use and survival outcomes. RESULTS: Forty-three patients were identified, with 95% of the patients receiving R-CHOP. CRT was given in 5 patients. Five-year event-free survival was 79% (95% confidence interval: 64%-89%) and 5-year overall survival was 88% (95% confidence interval: 73%-95%). Seven of 9 patients with DS4 did not receive CRT and instead monitored with serial PET scans. None of these 7 patients relapsed in the mediastinum. CONCLUSION: CRT may be omitted in patients with a negative end of treatment PET scans; however, careful observation may also obviate the need for CRT in PET positive patients.

High pretreatment disease burden as a risk factor for infectious complications following CD19 chimeric antigen receptor T-cell therapy for large B-cell lymphoma.

Infection has emerged as the chief cause of non-relapse mortality (NRM) post CD19-targeting chimeric antigen receptor T-cell therapy (CAR-T) therapy. Even though up to 50% of patients may remain infection-free, many suffer multiple severe, life-threatening, or fatal infectious events. The primary aim of this study was to explore severe and life-threatening infections post licensed CAR-T therapy in large B-cell lymphoma, with a focus on the role of disease burden and disease sites in assessing individual risk. We sought to understand the cohort of patients who experience ≥2 infections and those at the highest risk of infectious NRM. Our analysis identifies a higher disease burden after bridging therapy as associated with infection events. Those developing ≥2 infections emerged as a uniquely high-risk cohort, particularly if the second (or beyond) infection occurred during an episode of immune effector cell-associated neurotoxicity syndrome (ICANS) or while on steroids and/or anakinra for ICANS. Herein, we also describe the first reported cases of "CAR-T cold sepsis," a phenomenon characterized by the lack of an appreciable systemic inflammatory response at the time of detection of infection. We propose a risk-based strategy to encourage heightened clinician awareness of cold sepsis, with a view to reducing NRM.

Brexucabtagene autoleucel for relapsed or refractory mantle cell lymphoma in the United Kingdom: A real-world intention-to-treat analysis.

Brexucabtagene autoleucel (brexu-cel) is an autologous CD19 CAR T-cell product, approved for relapsed/refractory (r/r) mantle cell lymphoma (MCL). In ZUMA-2, brexu-cel demonstrated impressive responses in patients failing ≥2 lines, including a bruton's tyrosine kinase inhibitor, with an overall and complete response rate of 93% and 67%, respectively. Here, we report our real-world intention-to-treat (ITT) outcomes for brexu-cel in consecutive, prospectively approved patients, from 12 institutions in the United Kingdom between February 2021 and June 2023, with a focus on feasibility, efficacy, and tolerability. Of 119 approved, 104 underwent leukapheresis and 83 received a brexu-cel infusion. Progressive disease (PD) and/or manufacturing (MF) were the most common reasons for failure to reach harvest and/or infusion. For infused patients, best overall and complete response rates were 87% and 81%, respectively. At a median follow-up of 13.3 months, median progression-free survival (PFS) for infused patients was 21 months (10.1-NA) with a 6- and 12-month PFS of 82% (95% confidence interval [CI], 71-89) and 62% (95% CI, 49-73), respectively. ≥Grade 3 cytokine release syndrome and neurotoxicity occurred in 12% and 22%, respectively. On multivariate analysis, inferior PFS was associated with male sex, bulky disease, ECOG PS > 1 and previous MF. Cumulative incidence of non-relapse mortality (NRM) was 6%, 15%, and 25% at 6, 12, and 24 months, respectively, and mostly attributable to infection. Outcomes for infused patients in the UK are comparable to ZUMA-2 and other real-world reports. However, ITT analysis highlights a significant dropout due to PD and/or MF. NRM events warrant further attention.

Treatment outcomes in patients with large B-cell lymphoma after progression to chimeric antigen receptor T-cell therapy.

Over 60% of relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients who receive chimeric antigen receptor (CAR) T cells will experience disease progression. There is no standard next line of therapy and information in this setting is scarce and heterogeneous. We analyzed 387 R/R LBCL patients who progressed after CAR T cells from July 2018 until March 2022 in Spain and the United Kingdom. Median overall survival (OS) was 5.3 months, with significant differences according to the interval between infusion and progression (<2 months [1.9 months], 2-6 months [5.2 months], and >6 months [not reached]). After progression, 237 (61%) patients received treatment. Focusing on the first subsequent therapy, overall (complete) response rates were 67% (38%) for polatuzumab-bendamustine-rituximab (POLA), 51% (36%) for bispecific antibodies (BsAb), 45% (35%) for radiotherapy (RT), 33% (26%) for immune checkpoint inhibitors (ICIs), 25% (0%) for lenalidomide (LENA), and 25% (14%) for chemotherapy (CT). In terms of survival, 12-month progression-free survival and OS was 36.2% and 51.0% for POLA, 32.0% and 50.1% for BsAb, 30.8% and 37.5% for RT, 29.9% and 27.8% for ICI, 7.3% and 20.8% for LENA, and 6.1% and 18.3% for CT. Thirty-two (14%) patients received an allogeneic hematopoietic cell transplant with median OS not reached after a median follow-up of 15.1 months. In conclusion, patients with R/R LBCL who progress within the first 2 months after CAR T-cell therapy have dismal outcomes. Novel targeted agents, such as polatuzumab and BsAbs, can achieve prolonged survival after CAR T-cell therapy failure.

Development and validation of the post-CAR prognostic index for large B-cell lymphoma patients after CAR-T progression in third or later line treatment.

Chimeric antigen receptor (CAR) T-cell therapy fails to achieve durable responses in over 60% of relapsed/refractory (R/R) large B-cell lymphoma (LBCL) patients in the third or later line setting. After CAR-T failure, survival outcomes are heterogeneous and a prognostic model in this patient population is lacking. A training cohort of 216 patients with progressive disease (PD) after CAR-T from 12 Spanish centers was used to develop the Post-CAR Prognostic Index (PC-PI); primary endpoint was overall survival (OS) from CAR-T progression. Validation was performed in an external cohort from three different European centers (n = 204). The prognostic score incorporated five variables, assessed at time of PD to CAR-T: ECOG (> 0), hemoglobin (< 10 g/dL), LDH (≥ 2xULN), number of extranodal sites (> 1) and time from CAR-T to PD (< 4 months). Patients were classified in four risk groups with distinct OS (p-value < 0.05 in all comparisons). In the validation cohort, median OS in the low (31%), intermediate-low (26%), intermediate-high (17%) and high risk (26%) were 15.7, 7.1, 1.8 and 1.0 months, respectively (p < 0.05 in all comparisons). Results were consistent following adjustment for subsequent treatment. In the external cohort, the PC-PI showed a C-statistic of 0.79 (95%CI 0.76-0.82), outperforming IPI and R-IPI. In conclusion, the PC-PI score is a novel tool for OS prediction and could facilitate risk-adapted management of LBCL patients relapsing after CAR T-cells. Additionally, these results will help stratification and interpretation of trials and real-world data incorporating CART-exposed patients.

Overexpression of LEF1 predicts unfavorable outcome in adult patients with B-precursor acute lymphoblastic leukemia.

Aberrant activation of the Wnt pathway plays a pathogenetic role in various tumors and has been associated with adverse outcome in acute lymphoblastic leukemia (ALL). LEF1, a key mediator of Wnt signaling, has been linked to leukemic transformation, and recurrent mutations of LEF1 have been identified in pediatric T-ALL. Here we evaluated the prognostic significance of LEF1 expression in B-precursor ALL patients. LEF1 expression was determined by quantitative real-time RT-PCR in 282 adult B-precursor ALL patients treated on 06/99 and 07/03 GMALL trials. Patients were grouped into quartiles (Q1-Q4) according to LEF1 expression levels (LEF1 high, Q4; n = 71; LEF1 low, Q1-Q3; n = 211). Patients with high LEF1 expression had a significantly shorter relapse-free survival (RFS) compared with low LEF1 expressers (5-year RFS: LEF1 high, 27%; LEF1 low, 47%; P = .05). Importantly, high LEF1 expression was also associated with inferior RFS in standard-risk patients and was independently predictive for RFS (P = .02) in multivariate analyses for this subgroup. Thus, high LEF1 expression identifies B-precursor ALL patients with inferior RFS, supporting a pathogenetic role of Wnt signaling in ALL. Standard-risk patients with high LEF1 expression might benefit from early treatment modifications and new molecular therapies, including agents targeting the Wnt pathway.

Fludarabine-Melphalan-Campath, Followed by Unmanipulated Peripheral-Blood Haematopoietic Stem Cells, Can Still Cure Lymphoma.

Background: The second decade of this millennium was characterized by a widespread availability of chimeric antigen receptor T-cell (CAR-T) therapies to treat relapsed and refractory lymphomas. As expected, the role and indication of allogeneic haematopoietic stem cell transplant (allo-HSCT) in the management of lymphoma changed. Currently, a non-neglectable proportion of patients will be considered candidate for an allo-HSCT, and the debate of which transplant platform should be offered is still active. Objectives: to report the outcome of patients affected with relapsed/refractory lymphoma and transplanted following reduced intensity conditioning at King's College Hospital, London, between January 2009 and April 2021. Methods: Conditioning was with 150mg/m2 of fludarabine and melphalan of 140mg/m2. The graft was unmanipulated G-CSF mobilized peripheral blood haematopoietic stem cells (PBSC). Graft-versus-host disease (GVHD) prophylaxis consisted of pre-transplant Campath at the total dose of 60 mg in unrelated donors and 30 mg in fully matched sibling donors and ciclosporin. Results: One-year and five years OS were 87% and 79.9%, respectively, and median OS was not reached. The cumulative incidence of relapse was 16%. The incidence of acute GVHD was 48% (only grade I/II); no cases of grade III/IV were diagnosed. Chronic GVHD occurred in 39% of patients. TRM was 12%, with no cases developed within day 100 and 18 months after the procedure. Conclusions: The outcomes of heavily pretreated lymphoma patients are favorable, with median OS and survival not reached after a median of 49 months. In conclusion, even if some lymphoma subgroups cannot be treated (yet) with advanced cellular therapies, this study confirms the role of allo-HSCT as a safe and curative strategy.

Effective bridging therapy can improve CD19 CAR-T outcomes while maintaining safety in patients with large B-cell lymphoma.

The impact of bridging therapy (BT) on CD19-directed chimeric antigen receptor T-cell (CD19CAR-T) outcomes in large B-cell lymphoma (LBCL) is poorly characterized. Current practice is guided through physician preference rather than established evidence. Identification of effective BT modalities and factors predictive of response could improve both CAR-T intention to treat and clinical outcomes. We assessed BT modality and response in 375 adult patients with LBCL in relation to outcomes after axicabtagene ciloleucel (Axi-cel) or tisagenlecleucel (Tisa-cel) administration. The majority of patients received BT with chemotherapy (57%) or radiotherapy (17%). We observed that BT was safe for patients, with minimal morbidity or mortality. We showed that complete or partial response to BT conferred a 42% reduction in disease progression and death after CD19CAR-T therapy. Multivariate analysis identified several factors associated with likelihood of response to BT, including response to last line therapy, the absence of bulky disease, and the use of polatuzumab-containing chemotherapy regimens. Our data suggested that complete or partial response to BT may be more important for Tisa-cel than for Axi-cel, because all patients receiving Tisa-cel with less than partial response to BT experienced frank relapse within 12 months of CD19CAR-T infusion. In summary, BT in LBCL should be carefully planned toward optimal response and disease debulking, to improve patient outcomes associated with CD19CAR-T. Polatuzumab-containing regimens should be strongly considered for all suitable patients, and failure to achieve complete or partial response to BT before Tisa-cel administration may prompt consideration of further lines of BT where possible.

Severe cytopenia after CD19 CAR T-cell therapy: a retrospective study from the EBMT Transplant Complications Working Party.

We investigated the incidence and outcome of anti-CD19 chimeric antigen receptor (CAR) T-cells-associated Common Terminology Criteria for Adverse Events (CTCAE) ≥grade 3 cytopenia. In the EBMT CAR-T registry, we identified 398 adult patients with large B-cell lymphoma who had been treated with CAR-T-cells with axicel (62%) or tisacel (38%) before August 2021 and had cytopenia status documented for the first 100 days. Most patients had received two or three previous lines of therapy, however, 22.3% had received four or more. Disease status was progressive in 80.4%, stable in 5.0% and partial/complete remission in 14.6%. 25.9% of the patients had received a transplantation before. Median age was 61.4 years (min-max; IQR=18.7-81; (52.9-69.5)).The cumulative incidence of ≥grade 3 cytopenia was 9.0% at 30 days (95% CI (6.5 to 12.1)) and 12.1% at 100 days after CAR T-cell infusion (95% CI (9.1 to 15.5)). The median time from CAR-T infusion to cytopenia onset was 16.5 days (min-max; IQR=1-90; (4-29.8)). Grade 3 and grade 4 CTCAE cytopenia occurred in 15.2% and 84.8%, respectively. In 47.6% there was no resolution.Severe cytopenia had no significant impact on overall survival (OS) (HR 1.13 (95% CI 0.74 to 1.73), p=0.57). However, patients with severe cytopenia had a poorer progression-free survival (PFS) (HR 1.54 (95% CI 1.07 to 2.22), p=0.02) and a higher relapse incidence (HR 1.52 (95% CI 1.04 to 2.23), p=0.03). In those patients who developed severe cytopenia during the first 100 days (n=47), OS, PFS, relapse incidence and non-relapse mortality at 12 months after diagnosis of severe cytopenia were 53.6% (95% CI (40.3 to 71.2)), 20% (95% CI (10.4 to 38.6)), 73.5% (95% CI (55.2 to 85.2)) and 6.5% (95% CI (1.7 to 16.2)), respectively.In multivariate analysis of severe cytopenia risk factors, only year of CAR-T infusion (HR=0.61, 95% CI (0.39 to 0.95), p=0.028) and total number of treatment lines before CAR-T infusion (one or two lines vs three or more, HR=0.41, 95% CI (0.21 to 0.83), p=0.013) had a significant positive association with the incidence of cytopenia. Other factors, such as previous transplantation, disease status at time of CAR-T, patient age and patient sex, had no significant association.Our data provide insight on frequency and clinical relevance of severe cytopenia after CAR T-cell therapy in the European real-world setting.

High BAALC expression predicts chemoresistance in adult B-precursor acute lymphoblastic leukemia.

Overexpression of BAALC is an adverse prognostic factor in adults with cytogenetically normal acute myeloid leukemia and T-cell acute lymphoblastic leukemia (ALL). Here, we analyzed the prognostic significance of BAALC in B-precursor ALL. BAALC MRNA expression was determined in 368 primary adult B-precursor ALL patients enrolled on the 06/99 and 07/03 GMALL trials. Patients were grouped into tertiles according to BAALC expression (T1-T3). Higher BAALC expression (T3 vs T2 vs T1) was associated with higher age (P < .001), a higher white blood cell count (P = .008), CD34 (P = .001), BCR-ABL (P < .001), and MLL-AF4 (P < .001). Higher BAALC expression predicted primary therapy resistance in the overall cohort (P = .002) and in the BCR-ABL(-) and MLL-AF4(-) subgroup (P = .01). In BCR-ABL(-) and MLL-AF4(-) patients, higher BAALC expression was associated with a shorter overall survival (OS; 5-year OS: T3, 38%; T2, 52%; T1, 70%; P = .004) and independently predicted OS in multivariate models (P = .03). Gene-expression profiling revealed an up-regulation of stem cell markers and genes involved in chemoresistance (TSPAN7 and LYN) in the high BAALC group. Thus, high BAALC expression is associated with an immature, chemoresistant leukemic phenotype and identifies patients with inferior OS. Determination of BAALC might contribute to risk assessment of molecularly undefined adult B-precursor ALL.