Understanding and Managing Large B Cell Lymphoma Relapses after Chimeric Antigen Receptor T Cell Therapy

CAR T-cell therapy landscape in pediatric, adolescent and young adult oncology - A comprehensive analysis of clinical trials

Chimeric Antigen Receptor (CAR) T-cell therapy has emerged as a transformative approach in cancer treatment, particularly for hematologic malignancies. This therapy involves the genetic modification of patients' T-cells to target specific tumor antigens, bypassing the traditional MHC-TCR-mediated recognition. This innovation marks a significant step toward personalized medicine and precision oncology. In the pediatric, adolescent, and young adult (P-AYA) populations, Tisagenlecleucel (Kymriah®) exemplifies the success of CAR T-cell therapy, demonstrating significant efficacy in treating relapsed or refractory acute lymphoblastic leukemia (r/r ALL). However, the development of CAR T-cell therapies for P-AYA patients has not progressed as rapidly as for adults, with only one FDA approval for pediatric applications compared to six for adults up to 2024. Several challenges hinder the development of pediatric CAR T-cell therapies, including complex production logistics, limited clinical site access, restrictive patient eligibility criteria, and financial constraints, necessitating more effective incentives for pediatric oncology drug development independent of adult indications. To assess the current landscape of CAR T-cell therapy in P-AYA oncology, we conducted a comprehensive review of clinical trials registered on ClinicalTrials.gov up to May 2024. Our analysis included 77 trials exclusively targeting the P-AYA population from an initial pool of 40,690 studies filtered by age, dates, and specific criteria related to CAR T-cell interventions in cancer therapy. We found that 45 % of these trials originated from the USA and 30 % from China. The data retrieved from these trials provided insights into various aspects, including histological categories, antigenic targets, CAR-T generations, costimulatory domains, manufacturing processes, geographical distribution, and funding sources. This review highlighted a predominant focus on hematologic malignancies, particularly B-cell acute lymphoblastic leukemia (B-ALL), with significant attention to dual antigen targeting (CD19 and CD22) to address resistance mechanisms. Emerging targets such as GD2 for solid tumors and B7-H3 for various cancers also showed promise. Additionally, most trials still utilize second-generation CAR-T constructs with 4-1BB costimulatory domains, reflecting a conservative approach in pediatric populations. Our findings underscore the disparity in CAR T-cell therapy development between pediatric and adult populations, driven by distinct biological, ethical, and economic considerations. Pediatric cancers require specialized treatments tailored to the unique biology and genetic makeup of pediatric oncology. However, research and drug development have historically focused less on pediatric needs. Despite legislative efforts to promote pediatric oncology drug development, significant gaps remain. Clinical trials for P-AYA populations face challenges in patient enrollment, trial design, and funding, often relying on academic and non-profit institutions. Addressing these barriers is critical for advancing CAR T-cell therapy in pediatric oncology, improving outcomes, and ensuring equitable access to innovative treatments for these vulnerable populations. This review aims to inform future research and policy decisions, promoting advancements in CAR T-cell therapy for P-AYA cancer patients.

Be cautious to adopt a second CAR T-cell infusion after failure of CD19/CD22 cocktail CAR T-cell therapy in relapsed/refractory B-NHL

Chimeric antigen receptor (CAR) T-cell infusion (CTI) therapy has emerged as a breakthrough therapy in relapsed/refractory B-cell non-Hodgkin's lymphoma (R/R B-NHL), but a substantial number of patients still suffer treatment failure. Data on disease history, subsequent salvage therapies, and outcomes of patients who face treatment failure after the first CTI (CTI1) have not been reported in detail or systematically studied. Here, a retrospective analysis was performed on a total of 61 R/R B-NHL patients in whom salvage therapies were adopted after CTI1 treatment failure, with their clinical characteristics, subsequent management and outcomes described in detail. The results suggested that second-time CTI (CTI2) used as salvage therapy after failure of CTI1 could achieve a better transient overall response rate (ORR) than other salvage treatments (non-CTI2) in only a minority of patients (8/27 vs. 2/34, P=0.014). Nevertheless, the non-CTI2 group showed better event-free survival (EFS) (P = 0.007) and overall survival (OS) (P = 0.048) than the CTI2 group, with a median follow-up of 6.7 months vs. 4.7 months. In addition, univariate and multivariate analyses showed that only the status of the tumor at disease onset was an independent risk factor for survival; salvage therapy after CTI1 treatment failure was not. The adverse effects of CTI2 treatment were generally similar to those of non-CTI2 treatment, but the infection-related mortality was considerably higher. In conclusion, the prognosis of patients who fail CTI1 therapy is very poor regardless of the subsequent salvage therapies, and clinicians should be cautious about adopting CTI2 treatment after failure of treatment with the CD19/22 cocktail CTI1 in R/R B-NHL. Large-scale prospective studies are warranted, and new strategies are urgently needed to prevent treatment failure and improve the survival of B-cell lymphoma patients in future.

Predictive value of prognostic nutritional index as prognostic biomarkers in patients with lymphoma: a systematic review and meta-analysis

BACKGROUND

Several research have indicated the significant potential of the Prognostic Nutritional Index (PNI) as a prognostic biomarker in lymphoma patients. However, there is some inconsistency in the findings of a few studies. Hence, to offer a thorough evaluation of the predictive significance of PNI in lymphoma patients, we performed a meta-analysis to examine the prognostic value of PNI for survival outcomes in lymphoma patients.

METHODS

We conducted a comprehensive search for pertinent works published up until December 2023 in databases such as PubMed, EMBASE, Cochrane Library, and Web of Science. We obtained hazard ratio (HR) data related to survival outcomes and computed aggregated HRs with their corresponding 95% confidence intervals (CIs) to evaluate the correlation between PNI and both overall survival (OS) and progression-free survival (PFS) in lymphoma patients.

RESULTS

By analyzing data from 1260 patients in 28 studies, we found that PNI levels were associated with prognosis in lymphoma patients. High PNI levels predicted that patients had longer OS (HR: 0.46, 95% CI 0.37-0.58, P < 0.05) and better PFS (HR: 0.56, 95% CI 0.45-0.70, P < 0.05). Subgroup analyses showed that the predictive ability of PNI for patient prognosis may differ depending on the type of lymphoma. In addition, we found that the critical PNI value had greater predictive potential at 40-45 and above 45.

CONCLUSION

Our study suggests a strong association between PNI and prognostic outcomes in lymphoma patients, indicating that PNI holds substantial prognostic value in this population.

Engineering next-generation chimeric antigen receptor-T cells: recent breakthroughs and remaining challenges in design and screening of novel chimeric antigen receptor variants

Chimeric antigen receptor (CAR) T cells are a powerful treatment against hematologic cancers. The functional phenotype of a CAR-T cell is influenced by the domains that comprise the synthetic receptor. Typically, the potency of therapeutic CAR-T cell candidates is assessed by preclinical functional assays and mouse models (i.e. human tumor xenografts). However, to date, only a few sets of domains (e.g. CD8, CD28, 41BB) have been extensively tested in preclinical assays and human clinical studies. To characterize the efficiency of a CAR, different assays have been utilized to analyze T cell phenotypes, such as expansion, cytotoxicity, secretome, and persistence. However, each of these previous studies evaluated the importance of an assay differently, resulting in a wide range of functionally diverse CARs. In this review, we highlight recent (high-throughput) methods to analyze CAR domains and demonstrate their impact on inducing T cell phenotypes and activity. We also describe advances in computational methods and their potential for identifying CAR variants with enhanced properties. Finally, we reflect on the need for a standardized scoring system to support the clinical development of next-generation CARs.

How lactate affects immune strategies in lymphoma

Tumor cells undergo metabolic reprogramming through shared pathways, resulting in a hypoxic, acidic, and highly permeable internal tumor microenvironment (TME). Lactate, once only regarded as a waste product of glycolysis, has an inseparable dual role with tumor immunity. It can not only provide a carbon source for immune cells to enhance immunity but also help the immune escape through a variety of ways. Lymphoma also depends on the proliferation signal of TME. This review focuses on the dynamic process of lactate metabolism and immune function changes in lymphoma and aims to comprehensively summarize and explore which genes, transcription factors, and pathways affect the biological changes and functions of immune cells. To deeply understand the complex and multifaceted role of lactate metabolism and immunity in lymphoma, the combination of lactate targeted therapy and classical immunotherapy will be a promising development direction in the future.

Real-world evaluation of health-related quality of life in patients with diffuse large B-cell lymphoma based on a multinational survey

Background

Real-world health-related quality of life (HRQoL) data in patients with diffuse large B-cell lymphoma (DLBCL) are scarce. This study is to compare patient-reported outcomes in patients with DLBCL across therapy lines and countries.

Methods

Data were derived from the Adelphi DLBCL Disease Specific Programme™ from January 2021 to May 2021, a survey of physicians and their DLBCL patients in France, Germany, Italy, Spain, United Kingdom (UK), and the United States (US).

Results

Overall, analysis was conducted on 441 patients with DLBCL across Europe and the US (mean age 64.6 years, 64% male); 68% had an Ann Arbor stage III and 69% had an Eastern Cooperative Oncology Group Performance Status of 0 to 1. The mean overall GHS/QoL was 54.1; patients on their 3L+ therapy had a lower mean GHS/QoL compared with patients on 1L/2L (P = 0.0033). Further to this, mean EQ-5D-5L utility score was reduced from 0.73 for patients on 1L therapy to 0.66 for patients on 3L+ therapies (P = 0.0149). Mean percentages of impairment while working and overall work impairment were lower for patients receiving 3L+ therapy (12.5% and 17.7%; respectively) than those on 1L therapy (35.6% and 33.8%; respectively). When comparing region, patients in the US had significantly better scores for all functioning and symptomatic scales (per EORTC QLQ-C30) and work impairment (per WPAI) vs. patients with DLBCL in Europe. WPAI scores indicate that the overall activity impairment in the US was 36.6% and in Europe ranged from 42.4% in the UK to 54.9% in Germany. Mean EQ-5D-5L utility score for the US was 0.80, compared to 0.60 - 0.80 across the countries in Europe. Regression analysis showed patients who relapsed after more than one year of treatment were associated with better patient reported outcomes than those who relapse after less than one year.

Conclusion

Patient-reported outcomes of DLBCL patients remain poor and patients continue to experience considerable morbidity.

Outcomes of subsequent antilymphoma therapies after second-line axicabtagene ciloleucel or standard of care in ZUMA-7

ABSTRACT

The optimal management of patients with relapsed/refractory large B-cell lymphoma (LBCL) after disease progression or lack of response to second-line (2L) therapy remains unclear. Here, we report outcomes among patients who received subsequent antilymphoma therapy per investigator discretion separately by their randomized 2L arm in ZUMA-7, namely axicabtagene ciloleucel (axi-cel) vs standard of care (SOC). Progression-free survival (PFS) and overall survival (OS) were calculated from 3L therapy initiation. In the SOC arm, 127 of 179 randomized patients (71%) received 3L therapy. Median PFS among those who received 3L cellular immunotherapy (n = 68) vs those who did not (n = 59) was 6.3 vs 1.9 months, respectively; median OS was 16.3 vs 9.5 months, respectively. In the axi-cel arm, 84 of 180 randomized patients (47%) received 3L therapy. Median PFS among those who received 3L chemotherapy (n = 60) vs cellular immunotherapy (n = 8) was 1.7 vs 3.5 months, respectively; median OS was 8.1 months vs not reached, respectively. Of the 60 patients who received 3L chemotherapy, 10 underwent stem cell transplantation (SCT) after salvage chemotherapy. Median PFS was 11.5 vs 1.6 months, and median OS was 17.5 vs 7.2 months for those who did vs did not reach SCT, respectively. Eight patients received 3L cellular immunotherapy after 2L axi-cel. Of these, 6 patients received subsequent SCT in any line; all 6 were alive at data cutoff. These findings help inform subsequent treatment choices after 2L therapy failure for relapsed/refractory LBCL. The trial was registered at www.clinicaltrials.gov as #NCT03391466.

Role of FDG PET/CT in Patients With Lymphoma Treated With Chimeric Antigen Receptor T-Cell Therapy: Current Concepts

Chimeric antigen receptor (CAR) T-cell therapy is a cellular therapy in which the patient's T cells are enhanced to recognize and bind to specific tumor antigens. CAR T-cell therapy was initially developed for the treatment of leukemia, but its current main indication is the treatment of relapsed or refractory non-Hodgkin lymphoma. FDG PET/CT plays a fundamental role in the diagnosis, staging, therapy response assessment, and recurrence evaluation of patients with metabolically active lymphoma. Consistent with the examination's role in lymphoma management, FDG PET/CT is also the imaging modality of choice to evaluate patients before and after CAR T-cell therapy, and evidence supporting its utility in this setting continues to accumulate. In this article, we review current concepts in CAR T-cell therapy in patients with lymphoma, emphasizing the critical role of FDG PET/CT before and after therapy. A framework is presented that entails performing FDG PET/CT at four time points over the course of CAR T-cell therapy: pretherapy at baseline at the time of decision to administer CAR T-cell therapy and after any bridging therapies and posttherapy 1 and 3 months after infusion. PET parameters assessed at these time points predict various patient outcomes.

Current advances in experimental and computational approaches to enhance CAR T cell manufacturing protocols and improve clinical efficacy

Since the FDA's approval of chimeric antigen receptor (CAR) T cells in 2017, significant improvements have been made in the design of chimeric antigen receptor constructs and in the manufacturing of CAR T cell therapies resulting in increased in vivo CAR T cell persistence and improved clinical outcome in certain hematological malignancies. Despite the remarkable clinical response seen in some patients, challenges remain in achieving durable long-term tumor-free survival, reducing therapy associated malignancies and toxicities, and expanding on the types of cancers that can be treated with this therapeutic modality. Careful analysis of the biological factors demarcating efficacious from suboptimal CAR T cell responses will be of paramount importance to address these shortcomings. With the ever-expanding toolbox of experimental approaches, single-cell technologies, and computational resources, there is renowned interest in discovering new ways to streamline the development and validation of new CAR T cell products. Better and more accurate prognostic and predictive models can be developed to help guide and inform clinical decision making by incorporating these approaches into translational and clinical workflows. In this review, we provide a brief overview of recent advancements in CAR T cell manufacturing and describe the strategies used to selectively expand specific phenotypic subsets. Additionally, we review experimental approaches to assess CAR T cell functionality and summarize current in silico methods which have the potential to improve CAR T cell manufacturing and predict clinical outcomes.

Treatment strategies for relapse after CAR T-cell therapy in B cell lymphoma

Clinical trials of anti-CD19 chimeric antigen receptor T (CART19) cell therapy have shown high overall response rates in patients with relapsed/refractory B-cell malignancies. CART19 cell therapy has been approved by the US Food and Drug Administration for patients who relapsed less than 12 months after initial therapy or who are refractory to first-line therapy. However, durable remission of CART19 cell therapy is still lacking, and 30%-60% of patients will eventually relapse after CART19 infusion. In general, the prognosis of patients who relapse after CART19 cell therapy is poor, and various strategies to treat this patient population have been investigated extensively. CART19 failures can be broadly categorized by the emergence of either CD19-positive or CD19-negative lymphoma cells. If CD19 expression is preserved on the lymphoma cells, a second infusion of CART19 cells or reactivation of previously infused CART19 cells with immune checkpoint inhibitors can be considered. When patients develop CD19-negative relapse, targeting different antigens (e.g., CD20 or CD22) with CAR T cells, investigational chemotherapies, or hematopoietic stem cell transplantation are potential treatment options. However, salvage therapies for relapsed large B-cell lymphoma after CART19 cell therapy have not been fully explored and are conducted based on clinicians' case-by-case decisions. In this review, we will focus on salvage therapies reported to date and discuss the management of relapsed/refractory large B-cell lymphomas after CART19 cell therapy.

Four challenges to CAR T cells breaking the glass ceiling

Cell-based therapies using chimeric antigen receptor T cells (CAR T) have had dramatic efficacy in the clinic and can even mediate curative responses in patients with hematologic malignancies. As living drugs, engineered cells can still be detected in some patients even years after the original infusion. The excitement around the cell therapy field continues to expand as recent reports have shown that CAR T cells can induce remission in patients with autoimmune disease. While these promising advances in the field garner hope for wide-spread utility of CAR T therapies across diseases, several roadblocks exist that currently limit the access and efficacy of this therapy in the clinic. Herein, we will discuss four major obstacles that the CAR T field faces, including toxicity, identifying tumor-specific antigens, improving function in solid tumors, and reducing manufacturing complexity and cost. CAR T cells have potential for a multitude of diseases, but these glass ceilings will need to be broken in order to improve clinical responses and make this potentially life-saving therapy accessible to a larger patient population.

Efficacy of checkpoint inhibition after CAR-T failure in aggressive B-cell lymphomas: outcomes from 15 US institutions

Checkpoint inhibitor (CPI) therapy with anti-PD-1 antibodies has been associated with mixed outcomes in small cohorts of patients with relapsed aggressive B-cell lymphomas after CAR-T failure. To define CPI therapy efficacy more definitively in this population, we retrospectively evaluated clinical outcomes in a large cohort of 96 patients with aggressive B-cell lymphomas receiving CPI therapy after CAR-T failure across 15 US academic centers. Most patients (53%) had diffuse large B-cell lymphoma, were treated with axicabtagene ciloleucel (53%), relapsed early (≤180 days) after CAR-T (83%), and received pembrolizumab (49%) or nivolumab (43%). CPI therapy was associated with an overall response rate of 19% and a complete response rate of 10%. Median duration of response was 221 days. Median progression-free survival (PFS) and overall survival (OS) were 54 and 159 days, respectively. Outcomes to CPI therapy were significantly improved in patients with primary mediastinal B-cell lymphoma. PFS (128 vs 51 days) and OS (387 vs 131 days) were significantly longer in patients with late (>180 days) vs early (≤180 days) relapse after CAR-T. Grade ≥3 adverse events occurred in 19% of patients treated with CPI. Most patients (83%) died, commonly because of progressive disease. Only 5% had durable responses to CPI therapy. In the largest cohort of patients with aggressive B-cell lymphoma treated with CPI therapy after CAR-T relapse, our results reveal poor outcomes, particularly among those relapsing early after CAR-T. In conclusion, CPI therapy is not an effective salvage strategy for most patients after CAR-T, where alternative approaches are needed to improve post-CAR-T outcomes.

ICOS and OX40 tandem co-stimulation enhances CAR T-cell cytotoxicity and promotes T-cell persistence phenotype

Chimeric Antigen Receptor (CAR) T-cell therapies have emerged as an effective and potentially curative immunotherapy for patients with relapsed or refractory malignancies. Treatment with CD19 CAR T-cells has shown unprecedented results in hematological malignancies, including heavily refractory leukemia, lymphoma, and myeloma cases. Despite these encouraging results, CAR T-cell therapy faces limitations, including the lack of long-term responses in nearly 50-70% of the treated patients and low efficacy in solid tumors. Among other reasons, these restrictions are related to the lack of targetable tumor-associated antigens, limitations on the CAR design and interactions with the tumor microenvironment (TME), as well as short-term CAR T-cell persistence. Because of these reasons, we developed and tested a chimeric antigen receptor (CAR) construct with an anti-ROR1 single-chain variable-fragment cassette connected to CD3ζ by second and third-generation intracellular signaling domains including 4-1BB, CD28/4-1BB, ICOS/4-1BB or ICOS/OX40. We observed that after several successive tumor-cell in vitro challenges, ROR1.ICOS.OX40ζ continued to proliferate, produce pro-inflammatory cytokines, and induce cytotoxicity against ROR1+ cell lines in vitro with enhanced potency. Additionally, in vivo ROR1.ICOS.OX40ζ T-cells showed anti-lymphoma activity, a long-lasting central memory phenotype, improved overall survival, and evidence of long-term CAR T-cell persistence. We conclude that anti-ROR1 CAR T-cells that are activated by ICOS.OX40 tandem co-stimulation show in vitro and in vivo enhanced targeted cytotoxicity associated with a phenotype that promotes T-cell persistence.

The progress of novel strategies on immune-based therapy in relapsed or refractory diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) can be cured with standard front-line immunochemotherapy, whereas nearly 30-40% of patients experience refractory or relapse. For several decades, the standard treatment strategy for fit relapsed/refractory (R/R) DLBCL patients has been high-dose chemotherapy followed by autologous hematopoietic stem cell transplant (auto-SCT). However, the patients who failed in salvage treatment or those ineligible for subsequent auto-SCT have dismal outcomes. Several immune-based therapies have been developed, including monoclonal antibodies, antibody-drug conjugates, bispecific T-cell engaging antibodies, chimeric antigen receptor T-cells, immune checkpoint inhibitors, and novel small molecules. Meanwhile, allogeneic SCT and radiotherapy are still necessary for disease control for fit patients with certain conditions. In this review, to expand clinical treatment options, we summarize the recent progress of immune-related therapies and prospect the future indirections in patients with R/R DLBCL.

Theranostic chimeric antigen receptor (CAR)-T cells: Insight into recent trends and challenges in solid tumors

Cell therapy has reached significant milestones in various life-threatening diseases, including cancer. Cell therapy using fluorescent and radiolabeled chimeric antigen receptor (CAR)-T cell is a successful strategy for diagnosing or treating malignancies. Since cell therapy approaches have different results in cancers, the success of hematological cancers has yet to transfer to solid tumor therapy, leading to more casualties. Therefore, there are many areas for improvement in the cell therapy platform. Understanding the therapeutic barriers associated with solid cancers through cell tracking and molecular imaging may provide a platform for effectively delivering CAR-T cells into solid tumors. This review describes CAR-T cells' role in treating solid and non-solid tumors and recent advances. Furthermore, we discuss the main obstacles, mechanism of action, novel strategies and solutions to overcome the challenges from molecular imaging and cell tracking perspectives.

Failure of CAR-T cell therapy in relapsed and refractory large cell lymphoma and multiple myeloma: An urgent unmet need

Since its FDA approval, chimeric antigen receptor (CAR)-T cell therapy is changing the landscape of the treatment algorithm for relapsed and refractory large cell lymphoma and multiple myeloma. While initially hailed as a game changer and received widely with great enthusiasm, the reality of treatment failure soon became a major disappointment. This situation left patients and clinicians alike wondering about the next treatment options. CAR-T cell therapy failure for aggressive lymphoma or multiple myeloma creates a very poor prognosis and the treatment options are very limited. New emerging data, however, show promise for the use of approaches that include bispecific antibodies and other strategies to rescue affected patients. In this review, we summarize the current emerging data on the treatment options for patients whose disease has relapsed or remains refractory after CAR-T cell therapy failure, an area of great unmet need.

Predictive short/long-term efficacy biomarkers and resistance mechanisms of CD19-directed CAR-T immunotherapy in relapsed/refractory B-cell lymphomas

Genetically modified T-cell immunotherapies are revolutionizing the therapeutic options for hematological malignancies, especially those of B-cell origin. Impressive efficacies of CD19-directed chimeric antigen receptor (CAR)-T therapy have been reported in refractory/relapsed (R/R) B-cell non-Hodgkin lymphoma (NHL) patients who were resistant to current standard therapies, with a complete remission (CR) rate of approximately 50%. At the same time, problems of resistance and relapse following CAR-T therapy have drawn growing attention. Recently, great efforts have been made to determine various factors that are connected to the responses and outcomes following CAR-T therapy, which may not only allow us to recognize those with a higher likelihood of responding and who could benefit most from the therapy but also identify those with a high risk of resistance and relapse and to whom further appropriate treatment should be administered following CAR-T therapy. Thus, we concentrate on the biomarkers that can predict responses and outcomes after CD19-directed CAR-T immunotherapy. Furthermore, the mechanisms that may lead to treatment failure are also discussed in this review.

CAR T-Cell Persistence Correlates with Improved Outcome in Patients with B-Cell Lymphoma

Chimeric antigen receptor (CAR) T-cell therapy has led to profound and durable tumor responses in a relevant subset of patients with relapsed/refractory (r/r) B-cell lymphomas. Still, some patients show insufficient benefit or relapse after CAR T-cell therapy. We performed a retrospective study to investigate the correlation between CAR T-cell persistence in the peripheral blood (PB) at 6 months, assessed by droplet digital PCR (ddPCR), with CAR T-cell treatment outcome. 92 patients with r/r B-cell lymphomas were treated with CD19-targeting CAR T-cell therapies at our institution between 01/2019–08/2022. Six months post-treatment, 15 (16%) patients had no detectable circulating CAR-T constructs by ddPCR. Patients with CAR T-cell persistence had a significantly higher CAR T-cell peak (5432 vs. 620 copies/ug cfDNA, p = 0.0096), as well as higher incidence of immune effector cell-associated neurotoxicity syndrome (37% vs. 7%, p = 0.0182). After a median follow-up of 8.5 months, 31 (34%) patients relapsed. Lymphoma relapses were less frequent among patients with CAR T-cell persistence (29% vs. 60%, p = 0.0336), and CAR T-cell persistence in the PB at 6 months was associated with longer progression-free survival (PFS) (HR 2.79, 95% CI: 1.09–7.11, p = 0.0319). Moreover, we observed a trend towards improved overall survival (OS) (HR 1.99, 95% CI: 0.68–5.82, p = 0.2092) for these patients. In our cohort of 92 B-cell lymphomas, CAR T-cell persistence at 6 months was associated with lower relapse rates and longer PFS. Moreover, our data confirm that 4-1BB-CAR T-cells have a longer persistence as compared to CD-28-based CAR T-cells.

HLA-DR expression on monocytes and outcome of anti-CD19 CAR T-cell therapy for large B-cell lymphoma

Despite their unprecedented success in relapsed/refractory (R/R) large B-cell lymphoma (LBCL), anti-CD19 CAR T cells are associated with significant toxicity, and more than half of patients relapse. As monocytes emerged as key players in CAR therapy, we sought to evaluate the evolution of HLA-DR expression on monocytes (mHLA-DR) before and after commercial anti-CD19 CAR T-cell infusion in a large cohort (n = 103) of patients with R/R LBCL and its association with adverse events and treatment response. Cy-Flu-based lymphodepletion (LD) upregulated mHLA-DR in 79% of the cases, whereas in 2l% of cases (15 patients), the mHLA-DR level decreased after LD, and this decrease was associated with poorer outcome. Low mHLA-DR at day minus 7 (D-7) (<13 500 antibodies per cell) before CAR T-cell infusion correlated with older age, poorer performance status, higher tumor burden, and elevated inflammatory markers. With a median follow-up of 7.4 months, patients with low mHLA-DR D-7 exhibited a poorer duration of response and survival than the higher mHLA-DR D-7 group. For toxicity management, tocilizumab was more frequently used in the low-mHLA-DR D-7 group. These data suggest that monocyte dysregulation before LD, characterized by the downregulation of mHLA-DR, correlates with an inflammatory and immunosuppressive tumor environment and is associated with failure of anti-CD19 CAR T cells in patients with R/R LBCL. Modulation of these myeloid cells represents a promising field for improving CAR therapy.

Relapsed or refractory large B-cell lymphoma after chimeric antigen receptor T-cell therapy: Current challenges and therapeutic options

Chimeric antigen receptor (CAR) T-cell (CAR-T) therapy can provide durable remission in patients with relapsed or refractory diffuse large B-cell lymphoma (DLBCL) after failure of chemoimmunotherapy. However, patients who are refractory or relapsing after CAR-T therapy have poor outcomes. Multiple mechanisms of CAR-T therapy failure have been proposed but management of these patients remains a challenge. As CAR-T therapy moves earlier in the treatment of DLBCL, we urgently need trials focused on patients with relapse after CAR-T therapy. Recent advances in novel immunotherapies such as bispecific antibodies, antibody-drug conjugates and next-generation CAR-T therapies may provide avenues for treatment. Here we review the available data on using these drugs after failure of CAR-T therapy and provide a framework for the ideal sequencing of these novel agents.

Predictors and Management of Relapse to Axicabtagene Ciloleucel in Patients with Aggressive B-cell Lymphoma

OBJECTIVE/BACKGROUND

Despite the success of chimeric antigen receptor (CAR) T-cell therapy in patients with aggressive non-Hodgkin lymphoma (aNHL), some patients still fail treatment, and their prognosis is dismal.

METHODS

We performed a retrospective study of aNHL patients treated with axicabtagene ciloleucel (axi-cel) at two Mayo Clinic centers between 2018 and 2020. We evaluated predictive factors, toxicities, and responses to salvage regimens after CAR T-cell therapy.

RESULTS

Thirty-four patients received axi-cel with a median length of hospitalization of 14 days. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome of any grade occurred in 91% and 41% of patients, respectively. Furthermore, 71% of patients responded to therapy, with 53% achieving a complete response (CR). The CRS grade and absolute lymphocyte count at leukapheresis (ALC_Leuk) correlated with CR and overall survival (OS), respectively. After a median follow-up of 6.8 months (interquartile range [IQR] 4.6-14.9), 15 patients (44%) showed progressive disease (PD). Most patients (60%) progressed during the first 3 months and had persistent CD19 tumor expression. Elevated C-reactive protein at baseline increased the risk of PD, whereas elevated ferritin increased PD and mortality risk. Twelve patients received salvage therapy, but only three responded. Median OS of relapsed/refractory patients to axi-cel was 3 months (IQR 1.3-5.1).

CONCLUSION

The grade of CRS and ALC_Leuk correlated with better outcomes to axi-cel therapy. In addition, elevated inflammatory markers at baseline were associated with PD and shorter survival. Relapses after treatment frequently occur within months after axi-cel infusion; they confer a poor prognosis and create an urgent need for novel and effective treatment options in this patient population.

Outcomes of first therapy after CD19-CAR-T treatment failure in large B-cell lymphoma

Persistence or recurrence of large B-cell lymphoma after CD19-CAR-T is common, yet data guiding management are limited. We describe outcomes and features following CAR-T treatment failure. Of 305 adults who received CD19-CAR-T, 182 experienced disease recurrence or progression (1-year cumulative incidence 63% [95%CI: 57-69]). Of 52 post-CAR-T biopsies evaluated by flow cytometry, 49 (94%) expressed CD19. Subsequent anti-cancer treatment was administered in 135/182 (74%) patients with CAR-T treatment failure. Median OS from the first post-CAR-T treatment was 8 months (95%CI 5.6-11.0). Polatuzumab-, standard chemotherapy-, and lenalidomide-based treatments were the most common approaches after CAR-T. No complete responses (CRs) were observed with conventional chemotherapy, while CR rates exceeding 30% were seen following polatuzumab- or lenalidomide-based therapies. Factors associated with poor OS among patients treated post-CAR-T were pre-CAR-T bulky disease (HR 2.27 [1.10-4.72]), lack of response to CAR-T (2.33 [1.02-5.29]), age >65 years (HR 2.65 [1.49-4.73]) and elevated LDH at post-CAR-T treatment (HR 2.95 [1.61-5.38]). The presence of ≥2 of these factors was associated with inferior OS compared to ≤1 (56% vs. 19%). In this largest analysis to date of patients who progressed or relapsed after CD19-CAR-T, survival is poor, though novel agents such as polatuzumab and lenalidomide may have hold promise.

Characterization of the input material quality for the production of tisagenlecleucel by multiparameter flow cytometry and its relation to the clinical outcome

Tisagenlecleucel (tisa-cel) is a CD19^-specific CAR-T cell product approved for the treatment of relapsed/refractory (r/r) DLBCL or B-ALL. We have followed a group of patients diagnosed with childhood B-ALL (n = 5), adult B-ALL (n = 2), and DLBCL (n = 25) who were treated with tisa-cel under non-clinical trial conditions. The goal was to determine how the intensive pretreatment of patients affects the produced CAR-T cells, their in vivo expansion, and the outcome of the therapy. Multiparametric flow cytometry was used to analyze the material used for manufacturing CAR-T cells (apheresis), the CAR-T cell product itself, and blood samples obtained at three timepoints after administration. We present the analysis of memory phenotype of CD4/CD8 CAR-T lymphocytes (CD45RA, CD62L, CD27, CD28) and the expression of inhibitory receptors (PD-1, TIGIT). In addition, we show its relation to the patients' clinical characteristics, such as tumor burden and sensitivity to prior therapies. Patients who responded to therapy had a higher percentage of CD8⁺CD45RA⁺CD27⁺ T cells in the apheresis, although not in the produced CAR-Ts. Patients with primary refractory aggressive B-cell lymphomas had the poorest outcomes which was characterized by undetectable CAR-T cell expansion in vivo. No clear correlation of the outcome with the immunophenotypes of CAR-Ts was observed. Our results suggest that an important parameter predicting therapy efficacy is CAR-Ts' level of expansion in vivo but not the immunophenotype. After CAR-T cells' administration, measurements at several timepoints accurately detect their proliferation intensity in vivo. The outcome of CAR-T cell therapy largely depends on biological characteristics of the tumors rather than on the immunophenotype of produced CAR-Ts.

Outcomes of patients with aggressive B-cell lymphoma after failure of anti-CD19 CAR T-cell therapy: a DESCAR-T analysis

Anti-CD19 chimeric antigen receptor (CAR) T-cells represent a major advance in the treatment of relapsed/refractory aggressive B-cell lymphomas. However, a significant number of patients experience failure. Among 550 patients registered in the French registry DESCAR-T, 238 (43.3%) experienced progression/relapse, with a median follow-up of 7.9 months. At registration, 57.0% of patients presented an age-adjusted International Prognostic Index of 2 to 3, 18.9% had Eastern Cooperative Oncology Group performance status ≥2, 57.1% received >3 lines of treatment prior to receiving CAR T-cells, and 87.8% received bridging therapy. At infusion, 66% of patients presented progressive disease, and 38.9% had high lactate dehydrogenase (LDH). Failure after CAR T-cell treatment occurred after a median of 2.7 months (range: 0.2-21.5). Fifty-four patients (22.7%) presented very early failure (day [D] 0-D30); 102 (42.9%) had early failure (D31-D90), and 82 (34.5%) had late (>D90) failure. After failure, 154 patients (64%) received salvage treatment: 38.3% received lenalidomide, 7.1% bispecific antibodies, 21.4% targeted treatment, 11% radiotherapy, and 20% immunochemotherapy with various regimens. Median progression-free survival was 2.8 months, and median overall survival (OS) was 5.2 months. Median OS for patients failing during D0-D30 vs after D30 was 1.7 vs 3.0 months, respectively (P = .0001). Overall, 47.9% of patients were alive at 6 months, but only 18.9% were alive after very early failure. In multivariate analysis, predictors of OS were high LDH at infusion, time to CAR-T failure <D30, and high C-reactive protein at infusion. This multicentric analysis confirms the poor outcome of patients relapsing after CAR T-cell treatment, highlighting the need for further strategies dedicated to this population.

Efficacy, Safety, and Challenges of CAR T-Cells in the Treatment of Solid Tumors

Immunotherapy has been the fifth pillar of cancer treatment in the past decade. Chimeric antigen receptor (CAR) T-cell therapy is a newly designed adoptive immunotherapy that is able to target and further eliminate cancer cells by engaging with MHC-independent tumor-antigens. CAR T-cell therapy has exhibited conspicuous clinical efficacy in hematological malignancies, but more than half of patients will relapse. Of note, the efficacy of CAR T-cell therapy has been even more disappointing in solid tumors. These challenges mainly include (1) the failures of CAR T-cells to treat highly heterogeneous solid tumors due to the difficulty in identifying unique tumor antigen targets, (2) the expression of target antigens in non-cancer cells, (3) the inability of CAR T-cells to effectively infiltrate solid tumors, (4) the short lifespan and lack of persistence of CAR T-cells, and (5) cytokine release syndrome and neurotoxicity. In combination with these characteristics, the ideal CAR T-cell therapy for solid tumors should maintain adequate T-cell response over a long term while sparing healthy tissues. This article reviewed the status, clinical application, efficacy, safety, and challenges of CAR T-cell therapies, as well as the latest progress of CAR T-cell therapies for solid tumors. In addition, the potential strategies to improve the efficacy of CAR T-cells and prevent side effects in solid tumors were also explored.

Predictors of cytopenias after treatment with axicabtagene ciloleucel in patients with large B-cell lymphoma

Cytopenias are important but less studied adverse events following chimeric antigen receptor-engineered T cell (CAR-T) therapy. In our analysis of patients with large cell lymphoma who received axicabtagene ciloleucel (axi-cel), we sought to determine the rate and risk factors of clinically significant short term cytopenias defined as grade ≥3 neutropenia, anemia, or thrombocytopenia, or treatment with growth factors or blood product transfusions between days 20-30 after axi-cel. Fifty-three pts received axi-cel during the study period and severe cytopenias were observed in 32 (60%) pts. Significant cytopenias were more common in non-responders (stable or progressive disease) vs. responders (partial or complete response) (100% vs. 70%; p = .01). In the multivariable model, platelet transfusion within a month before leukapheresis, number of red blood cell and platelet transfusions between leukapheresis to lymphodepletion, pre-lymphodepletion absolute neurophil count, pre-lymphodepletion lactate dehydrogenase, and number of dexamethasone treatments after CAR-T were significantly associated with severe cytopenias after axi-cel.

CAR-T cell therapy for hematological malignancies: Limitations and optimization strategies

In the past decade, the emergence of chimeric antigen receptor (CAR) T-cell therapy has led to a cellular immunotherapy revolution against various cancers. Although CAR-T cell therapies have demonstrated remarkable efficacy for patients with certain B cell driven hematological malignancies, further studies are required to broaden the use of CAR-T cell therapy against other hematological malignancies. Moreover, treatment failure still occurs for a significant proportion of patients. CAR antigen loss on cancer cells is one of the most common reasons for cancer relapse. Additionally, immune evasion can arise due to the hostile immunosuppressive tumor microenvironment and the impaired CAR-T cells in vivo persistence. Other than direct antitumor activity, the adverse effects associated with CAR-T cell therapy are another major concern during treatment. As a newly emerged treatment approach, numerous novel preclinical studies have proposed different strategies to enhance the efficacy and attenuate CAR-T cell associated toxicity in recent years. The major obstacles that impede promising outcomes for patients with hematological malignancies during CAR-T cell therapy have been reviewed herein, along with recent advancements being made to surmount them.

Metabolic Imaging in B-Cell Lymphomas during CAR-T Cell Therapy

Simple Summary

Chimeric antigen receptor–engineered T cells are an innovative therapy in hematologic malignancies, especially in patients with refractory/relapsed B-cell lymphomas. Few studies have analyzed the role of [¹⁸F]FDG PET/CT in this field; this review aims to illustrate the literature data and the major findings related to [¹⁸F]FDG PET/CT use during CAR-T cell therapy in B-cell lymphomas, focusing on the prognostic value of metabolic parameters, as well as on response assessment. Furthermore, this work shows in detail the specific adverse events during CAR-T cell therapy and the role of [¹⁸F]FDG PET/CT imaging in their occurrence.

Abstract

Chimeric antigen receptor–engineered (CAR) T cells are emerging powerful therapies for patients with refractory/relapsed B-cell lymphomas. [¹⁸F]FDG PET/CT plays a key role during staging and response assessment in patients with lymphoma; however, the evidence about its utility in CAR-T therapies for lymphomas is limited. This review article aims to provide an overview of the role of PET/CT during CAR-T cell therapy in B-cell lymphomas, focusing on the prognostic value of metabolic parameters, as well as on response assessment. Data from the literature report on the use of [¹⁸F]FDG PET/CT at the baseline with two scans performed before treatment started focused on the time of decision (TD) PET/CT and time of transfusion (TT) PET/CT. Metabolic tumor burden is the most studied parameter associated with disease progression and overall survival, making us able to predict the occurrence of adverse effects. Instead, for post-therapy evaluation, 1 month (M1) PET/CT seems the preferable time slot for response assessment and in this setting, the Deauville 5-point scale (DS), volumetric analyses, SUVmax, and its variation between different time points (∆SUVmax) have been evaluated, confirming the usefulness of M1 PET/CT, especially in the case of pseudoprogression. Additionally, an emerging role of PET/CT brain scans is reported for the evaluation of neurotoxicity related to CAR-T therapies. Overall, PET/CT results to be an accurate method in all phases of CAR-T treatment, with particular interest in assessing treatment response. Moreover, PET parameters have been reported to be reliable predictors of outcome and severe toxicity.

Role of CD19 Chimeric Antigen Receptor T Cells in Second-Line Large B Cell Lymphoma: Lessons from Phase 3 Trials. An Expert Panel Opinion from the American Society for Transplantation and Cellular Therapy

Since 2017, 3 CD19-directed chimeric antigen receptor (CAR) T cell therapies-axicabtagene ciloleucel, tisagenlecleucel, and lisocabtagene maraleucel-have been approved for relapsed/refractory aggressive diffuse large B cell lymphoma after 2 lines of therapy. Recently, 3 prospective phase 3 randomized clinical trials were conducted to define the optimal second-line treatment by comparing each of the CAR T cell products to the current standard of care: ZUMA-7 for axicabtagene ciloleucel, BELINDA for tisagenlecleucel, and TRANSFORM for lisocabtagene maraleucel. These 3 studies, although largely addressing the same question, had different outcomes, with ZUMA-7 and TRANSFORM demonstrating significant improvement with CD19 CAR T cells in second-line therapy compared with standard of care but BELINDA not showing any benefit. The US Food and Drug Administration has now approved axicabtagene ciloleucel and lisocabtagene maraleucel for LBCL that is refractory to first-line chemoimmunotherapy or relapse occurring within 12 months of first-line chemoimmunotherapy. Following the reporting of these practice changing studies, here a group of experts convened by the American Society for Transplantation and Cellular Therapy provides a comprehensive review of the 3 studies, emphasizing potential differences, and shares perspectives on what these results mean to clinical practice in this new era of treatment of B cell lymphomas.

MDSCs and T cells in solid tumors and non-Hodgkin lymphomas: an immunosuppressive speech

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous subset of cells expanded during multiple pathological settings, including cancers. In tumors, MDSCs are dominant drivers of T-cell immunosuppression. To accomplish their job, they exploit multiple mechanisms ultimately leading to the paralysis of anti-tumor immunity. Among the variety of MDSC-ways of working within the tumor microenvironment, the generation of reactive species and the metabolic reprogramming have emerged as pivotal determinants of their immunosuppressive power. In this review we will overview integral mechanisms of MDSC-mediated immunosuppression in solid tumors, with a particular focus on Non-Hodgkin lymphoma.

Glofitamab Treatment in Relapsed or Refractory DLBCL after CAR T-Cell Therapy

Simple Summary

CAR T-cell therapies represent a major advance in the treatment of relapsed B-cell non-Hodgkin lymphomas. Nevertheless, a significant proportion of these patients will experience disease progression following CAR T treatment. For these patients, no standard therapeutic procedure is established so far. The novel bispecific antibody glofitamab has shown promising activity in the treatment of refractory or relapsed B-cell non-Hodgkin lymphomas. In this study, we provide evidence for good tolerance and promising efficacy of glofitamab administration in patients relapsing after CAR T-cell therapy.

Abstract

Chimeric antigen receptor T-cells (CAR T) treatment has become a standard option for patients with diffuse large B-cell lymphomas (DLBCL), which are refractory or relapse after two prior lines of therapy. However, little evidence exists for treatment recommendations in patients who relapse after CAR T-cell treatment and the outcome for such patients is poor. In this study, we evaluated the safety and efficacy of a monotherapy with the bispecific CD20xCD3 antibody glofitamab in patients who progressed after CAR T treatment. We report nine consecutive patients with progressive DLBCL after preceding CAR T-cell therapy. The patients received a maximum of 12 cycles of glofitamab after a single obinutuzumab pre-treatment at an academic institution. CRS was observed in two patients (grade 2 in both patients). We observed an overall response rate of 67%, with four patients achieving a complete response and a partial remission in two patients. Interestingly, we identified increased persistence of circulating CAR T-cells in peripheral blood in three of the five patients with measurable CAR T-cells. Our data suggest that glofitamab treatment is well tolerated and effective in patients with DLBCL relapsing after CAR T-cell therapy and can enhance residual CAR T-cell activity.

Immunotherapy beyond cellular therapy in follicular lymphoma: A case of complete remission after failure of two CAR-T

Patients with relapsed follicular lymphoma who do not respond to CAR-T have a poor outcome. We present a case of refractory follicular lymphoma who relapsed after two CAR-T infusions and achieved a complete remission after treatment with obinutuzumab and lenalidomide. This represents a promising treatment option in the post-CAR-T setting.

Allogeneic Chimeric Antigen Receptor Therapy in Lymphoma

The therapeutic armamentarium has significantly expanded since the approval of various CD19-targeting chimeric antigen receptor T cell (CAR-T) therapies in non-Hodgkin lymphoma (NHL). These CAR-Ts are patient-specific and require a complex, resource, and time-consuming process. While this appears promising, autologous CAR-Ts are limited due to the lack of accessibility, manufacturing delays, and variable product quality. To overcome these, allogeneic (allo) CARs from healthy donors appear appealing. These can be immediately available as “off the shelf” ready-to-use products of standardized and superior quality exempt from the effects of an immunosuppressive tumor microenvironment and prior treatments, and potentially with lower healthcare utilization using industrialized scale production. Allogeneic CARs, however, are not devoid of complications and require genomic editing, especially with αβ T cells to avoid graft versus host disease (GvHD) and allo-rejection by the recipient’s immune system. Tools for genomic editing such as TALEN and CRISPR provide promise to develop truly “off the shelf” universal CARs and further advance the field of cellular immunotherapy. Several allogeneic CARs are currently in early phase clinical trials, and preliminary data is encouraging. Longer follow-up is required to truly assess the feasibility and safety of these techniques in the patients. This review focuses on the strategies for developing allogeneic CARs along with cell sources and clinical experience thus far in lymphoma.

Cachexia is a risk factor for negative clinical and functional outcomes in patients receiving chimeric antigen receptor T-cell therapy for B-cell non-Hodgkin lymphoma

Cachexia is a muscle-wasting syndrome that is known to impact the clinical course of several cancer populations but has not been specifically investigated in patients receiving chimeric antigen receptor T (CAR-T) cell therapy. In this study, we investigated the relationship between cachexia markers and several cancer and functional outcomes in a pilot population of aggressive B-cell non-Hodgkin lymphoma patients receiving CAR-T. We found that the prognostic nutritional index was linked to progression-free survival, overall survival, and disability-free survival, while several additional weight and serum-based markers of cachexia were also associated with negative outcomes. These data prompt further investigation of cachexia markers in populations receiving CAR-T cell therapy.

Beyond CD19 CAR-T cells in lymphoma

Adoptive transfer of CD19-specific chimeric antigen receptor T-cells (CAR-T cells) has transformed the treatment paradigm of relapsed/refractory (R/R) CD19 B-cell malignancies, dramatically improving remission rates and cures in patients with chemo-refractory disease. However, the applicability of CD19 CAR-T cells is limited to B cell malignancies and antigen loss can result in treatment failure, prompting the exploration of alternative targets to overcome tumor escape via CD19 antigen loss, as well as extend the CAR-T cell platform to treat Hodgkin and T cell lymphomas. This review highlights recent clinical trials testing CAR-T cell targets beyond CD19.

Megadose 90Y-ibritumomab tiuxetan prior to allogeneic transplantation is effective for aggressive large B-cell lymphoma

Allogeneic hematopoietic cell transplantation (allo-HCT) can be curative for relapsed or refractory B-cell lymphomas (BCLs), although outcomes are worse in aggressive disease, and most patients will still experience relapse. Radioimmunotherapy using 90Y-ibritumomab tiuxetan can induce disease control across lymphoma subtypes in a dose-dependent fashion. We hypothesized that megadoses of 90Y-ibritumomab tiuxetan with reduced-intensity conditioning could safely produce deeper remissions in aggressive BCL further maintained with the immunologic effect of allo-HCT. In this phase 2 study, CD20+ BCL patients received outpatient 90Y-ibritumomab tiuxetan (1.5 mCi/kg; maximum, 120 mCi), fludarabine, and then 2 Gy total body irradiation before HLA-matched allo-HCT. Twenty patients were enrolled after a median of 4.5 prior lines of therapy, including 14 with prior autologous transplant and 4 with prior anti-CD19 chimeric T-cellular therapy. A median 90Y-ibritumomab tiuxetan activity of 113.6 mCi (range, 71.2-129.2 mCi) was administered, delivering a median of 552 cGy to the liver (range, 499-2411 cGy). The estimated 1- and 5-year progression-free survival was 55% (95% confidence interval [CI], 31-73) and 50% (95% CI, 27-69) with a median progression-free survival of 1.57 years. The estimated 1- and 5-year overall survival was 80% (95% CI, 54-92) and 63% (95% CI, 38-81) with a median overall survival of 6.45 years. Sixteen patients (80%) experienced grade 3 or higher toxicities, although nonrelapse mortality was 10% at 1 year. No patients developed secondary acute myeloid leukemia/myelodysplastic syndrome. Megadose 90Y-ibritumomab tiuxetan, fludarabine, and low-dose total body irradiation followed by an HLA-matched allo-HCT was feasible, safe, and effective in treating aggressive BCL, exceeding the prespecified end point while producing nonhematologic toxicities comparable to those of standard reduced-intensity conditioning regimens.

Imaging Primer on Chimeric Antigen Receptor T-Cell Therapy for Radiologists

Chimeric antigen receptor (CAR) T-cell therapy is a recently approved breakthrough treatment that has become a new paradigm in treatment of recurrent or refractory B-cell lymphomas and pediatric or adult acute lymphoid leukemia. CAR T cells are a type of cellular immunotherapy that artificially enhances T cells to boost eradication of malignancy through activation of the native immune system. The CAR construct is a synthetically created functional cell receptor grafted onto previously harvested patient T cells, which bind to preselected tumor-associated antigens and thereby activate host immune signaling cascades to attack tumor cells. Advantages include a single treatment episode of 2-3 weeks and durable disease elimination, with remission rates of over 80%. Responses to therapy are more rapid than with conventional chemotherapy or immunotherapy, with intervening short-interval edema. CAR T-cell administration is associated with therapy-related toxic effects in a large percentage of patients, notably cytokine release syndrome, immune effect cell-associated neurotoxicity syndrome, and infections related to immunosuppression. Knowledge of the expected evolution of therapy response and potential adverse events in CAR T-cell therapy and correlation with the timeline of treatment are important to optimize patient care. Some toxic effects are radiologically evident, and familiarity with their imaging spectrum is key to avoiding misinterpretation. Other clinical toxic effects may be occult at imaging and are diagnosed on the basis of clinical assessment. Future directions for CAR T-cell therapy include new indications and expanded tumor targets, along with novel ways to capture T-cell activation with imaging. An invited commentary by Ramaiya and Smith is available online. Online supplemental material is available for this article. ^©RSNA, 2022.

Transformed Lymphoma Is Associated with a Favorable Response to CAR-T-Cell Treatment in DLBCL Patients

Simple Summary

The clinical features predicting favorable outcomes after CAR-T-cell treatment are a matter of ongoing debate. This study aimed to evaluate the potential importance of lymphoma subtypes regarding prognostic significance, mainly to compare transformed versus de novo DLBCL. We found that patients with transformed/secondary lymphoma have a decisively more favorable course after CAR-T-cell therapy than patients with de novo lymphoma.

Abstract

(1) Background: CAR-T-cell therapy is a novel therapeutic option for patients with relapsed/refractory diffuse large B-cell lymphoma (r/r DLBCL). The parameters that predict a favorable outcome after CAR-T-cell treatment are a matter of ongoing exploration. (2) Methods: We analyzed 36 consecutive patients with r/r DLBCL receiving tisagenlecleucel or axicabtagene ciloleucel at a single academic institution. We hypothesized that lymphoma subtypes (transformed versus de novo DLBCL) are of prognostic importance. We also assessed age, previous treatment, bridging therapy, remission status at the time of CAR-T treatment and at six months, LDH, the occurrence of CRS or ICANS, and CAR-T-DNA ddPCR kinetics for their prognostic impact. (3) Results: CRS was observed in 24 (67%) patients, and ICANS was observed in 14 (39%) patients. CR was achieved in 20 (56%) patients. Achievement of CR within six months after CAR-T was associated with better PFS (p < 0.0001) and OS (p < 0.0001). Remarkably, transformed (=secondary) lymphoma was associated with a better outcome than de novo disease for PFS (p = 0.0093) and OS (p = 0.0209), and the CR rate was 78% versus 33% (p = 0.0176). Mortality in patients with transformed DLBCL was 23% compared with 56% in de novo patients (p = 0.0209). (4) Conclusion: The presence of transformed DLBCL seems to be associated with a more favorable course after CAR-T treatment than that observed in the de novo DLBCL patients.

How to Sequence Therapies in Diffuse Large B-Cell Lymphoma Post-CAR-T Cell Failure

OPINION STATEMENT

Post CAR-T failures represent a new unmet need in R/R LBCL. The prognosis is usually very poor and standard treatment options that can guide clinicians are, unfortunately, not available. While polatuzumab, tafasitamab, selinexor, and loncastuximab tesirine are available as SOC since they are FDA approved, data is lacking in the post CAR-T setting. However, they could be used in the absence of other treatment options (clinical trials). A selected group of patients may be treated with checkpoint inhibitors, likely low tumor burden or low proliferative lymphomas or those with PD-L1 expression. For localized relapses, radiation therapy could be considered. A main consideration should be given to clinical trials. So far, it appears that bi-specific antibodies have the best encouraging data (high response rates) with manageable toxicities and logistics; thus, we recommend clinicians to enroll patients in clinical trials utilizing these agents. Other cell therapies (such as dual CAR-T or allogeneic products) should also be considered; however, challenges with logistics and further immunosuppression (especially if patients had prolonged cytopenias from prior CAR-T therapy) may affect its applicability right after CAR-T relapse. It is unclear whether these options will lead to long-term remissions; thus, consolidation with stem cell transplantation (either auto or allogeneic SCT) could be considered in eligible patients.

Clinical experience of CAR T cell therapy in lymphomas

Non-Hodgkin lymphoma in relapse portends a poor prognosis due to resistance to cytotoxic chemotherapy and monoclonal antibodies. Chimeric Antigen receptor (CAR) T cell therapy has been tested in many lymphomas in the relapse refractory setting and has resulted in durable responses despite some peculiar side effects including cytokine release syndrome (CRS), neurological events (NE), prolonged cytopenias and hypogammaglobulinemia. This review summarizes the registration trials conducted in lymphomas. All products showed response rates that were far better than obtainable by salvage chemotherapy and most patients recovered from side effects including CRS and NEs. The impact of CAR T in the real world setting was discussed as well as how to approach the use of CAR T in special circumstances such as CNS involvement, management of post CAR relapses and outpatient therapy.

Anti-CD19 chimeric antigen receptor T-cell therapy in B-cell lymphomas: current status and future directions

Aims:

To review recent data and relevant of the role of anti-CD19 chimeric antigen receptor (CAR) T-cell therapy for B-cell non-Hodgkin lymphoma (NHL).

Methods:

Review and compilation of the most recent and relevant data published in full text and abstract forms of anti-CD19 CAR T-cell therapy for B-cell NHL.

Results:

Different anti-CD19 CAR T-cell therapy products have been tested and shown significant clinical activity across B-cell NHL patients. The objective responses in relapsed DLBCL, FL and MCL were 50–83%, 83–93% and 93%, respectively.

Conclusions:

Anti-CD19 CAR T-cell therapy is a viable option for poor risk refractory B-cell NHLs.

Interventions and outcomes of adult patients with B-ALL progressing after CD19 chimeric antigen receptor T-cell therapy

CD19-targeted chimeric antigen receptor (CAR) T-cell therapy has become a breakthrough treatment of patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL). However, despite the high initial response rate, the majority of adult patients with B-ALL progress after CD19 CAR T-cell therapy. Data on the natural history, management, and outcome of adult B-ALL progressing after CD19 CAR T cells have not been described in detail. Herein, we report comprehensive data of 38 adult patients with B-ALL who progressed after CD19 CAR T therapy at our institution. The median time to progression after CAR T-cell therapy was 5.5 months. Median survival after post-CAR T progression was 7.5 months. A high disease burden at the time of CAR T-cell infusion was significantly associated with risk of post-CAR T progression. Thirty patients (79%) received salvage treatment of post-CAR T disease progression, and 13 patients (43%) achieved complete remission (CR), but remission duration was short. Notably, 7 (58.3%) of 12 patients achieved CR after blinatumomab and/or inotuzumab administered following post-CAR T failure. Multivariate analysis revealed that a longer remission duration from CAR T cells was associated with superior survival after progression following CAR T-cell therapy. In summary, overall prognosis of adult B-ALL patients progressing after CD19 CAR T cells was poor, although a subset of patients achieved sustained remissions to salvage treatments, including blinatumomab, inotuzumab, and reinfusion of CAR T cells. Novel therapeutic strategies are needed to reduce risk of progression after CAR T-cell therapy and improve outcomes of these patients.

Real-World Experience of Axicabtagene Ciloleucel and Tisagenlecleucel for Relapsed or Refractory Aggressive B-cell Lymphomas: A Single-Institution Experience

BACKGROUND

CD19-directed chimeric antigen T-cell receptor (CAR-T) therapies have revolutionized the treatment of patients with relapsed/refractory (R/R) aggressive B-cell lymphomas (aBCL). The results of the landmark ZUMA-1 and JULIET trials have been reproducible in real-world settings across multiple institutions, and patients with double (DHL) or triple (THL) hit lymphomas have demonstrated non-inferior outcomes compared to non-DHL/THL counterparts.

MATERIALS AND METHODS

This retrospective cohort study included 53 patients with R/R aBCL who received CAR-T from October 2017 to June 2020 at the University of California, Los Angeles. Patient characteristics, lymphoma-related variables and outcomes of interest were summarized using descriptive statistics and compared between groups by Fisher's exact test. Kaplan-Meier methods were used for analysis of OS, progression free survival (PFS), and duration of response (DOR). Univariate and multivariate cox regression analysis were performed to evaluate for significant prognostic variables.

RESULTS

With a median follow-up of 15.2 months, this cohort demonstrated overall response rate and complete response rate of 72% and 64% (n = 34), respectively. The median DOR, PFS and OS were not reached, 7.9 and 17.7 months, respectively. By univariate analysis, DHL/THL status was the only clinical feature significantly associated with relapse post-CAR-T (OR 5.9, P = .015).

CONCLUSIONS

Our single-institution, real-world cohort of R/R aBCL patients demonstrated similar efficacy outcomes to those of the ZUMA-1 and JULIET trials and published real-world studies. Our findings suggest DHL/THL patients may benefit from novel CAR-T constructs, maintenance strategies with immunomodulatory agents or allogeneic-HCT.

Trispecific CD19-CD20-CD22-targeting duoCAR-T cells eliminate antigen-heterogeneous B cell tumors in preclinical models

A substantial number of patients with leukemia and lymphoma treated with anti-CD19 or anti-CD22 monoCAR-T cell therapy relapse because of antigen loss or down-regulation. We hypothesized that B cell tumor antigen escape may be overcome by a chimeric antigen receptor (CAR) design that simultaneously targets three B cell leukemia antigens. We engineered trispecific duoCAR-T cells with lentiviral vectors encoding two CAR open reading frames that target CD19, CD20, and CD22. The duoCARs were composed of a CAR with a tandem CD19- and CD20-targeting binder, linked by the P2A self-cleaving peptide to a second CAR targeting CD22. Multiple combinations of intracellular T cell signaling motifs were evaluated. The most potent duoCAR architectures included those with ICOS, OX40, or CD27 signaling domains rather than those from CD28 or 4-1BB. We identified four optimal binder and signaling combinations that potently rejected xenografted leukemia and lymphoma tumors in vivo. Moreover, in mice bearing a mixture of B cell lymphoma lines composed of parental triple-positive cells, CD19-negative, CD20-negative, and CD22-negative variants, only the trispecific duoCAR-T cells rapidly and efficiently rejected the tumors. Each of the monoCAR-T cells failed to prevent tumor progression. Analysis of intracellular signaling profiles demonstrates that the distinct signaling of the intracellular domains used may contribute to these differential effects. Multispecific duoCAR-T cells are a promising strategy to prevent antigen loss-mediated relapse or the down-regulation of target antigen in patients with B cell malignancies.

Patterns and Predictors of Failure in Recurrent or Refractory Large B-Cell Lymphomas following Chimeric Antigen Receptor (CAR) T-Cell Therapy

PURPOSE

Chimeric antigen receptor T-cell (CAR T) therapy is capable of eliciting durable responses in patients with relapsed/refractory (R/R) lymphomas. However, the majority of treated patients relapse. Patterns of failure following CAR T have not been previously characterized and may provide insights into the mechanisms of resistance guiding future treatment strategies.

METHODS AND MATERIALS

Retrospective analysis of R/R large B-cell lymphoma patients treated with anti-CD19 CAR T at an NCI-designated Comprehensive Cancer Center from 2015 to 2019. Pre- and post-treatment PET/CTs were analyzed to assess the progression of existing (local failures) versus new, non-overlapping lesions (de novo failures) and to identify lesions at high-risk for progression.

RESULTS

A total of 469 pretreatment lesions in 63 patients were identified. At a median follow-up of 12•6 months, 36 (57%) patients recurred. The majority (n=31, 86%) had a component of local failure with 13 (36%) patients exhibiting strictly local failures. Even at progression, 84% of recurrent patients continued to have a subset of pretreatment lesions maintain PET/CT resolution. Lesions at high-risk for local failure included those with a diameter ≥5cm (OR 2•34, 95%CI 1•55-3•55; p<0•001), an SUV_max≥10 (OR 2•08, 95%CI 1•38-3•12; p<0•001), or that were extranodal (OR 1.49, 95% CI 1.10-2.04; p=0.01). In the 69 patients eligible for survival analysis, those with any lesion ≥5cm (n=46, 67%) experienced inferior PFS (HR 2•41, 95%CI 1•15-5•04; p=0•02) and OS (HR 3•36, 95%CI 1•17-9•96; p=0•02).

CONCLUSION

The majority of patients who recur following CAR T experience a component of local progression. Furthermore, lesions with high-risk features, particularly large size, were associated with inferior treatment efficacy and patient survival. Taken together, these observations suggest that lesion-specific resistance may contribute to CAR T treatment failure. Locally-directed therapies to high-risk lesions, such as radiotherapy, may be a viable strategy to prevent CAR T failures in select patients.

Efficacy and Safety of Axicabtagene Ciloleucel and Tisagenlecleucel Administration in Lymphoma Patients With Secondary CNS Involvement: A Systematic Review

Background

The efficacy and safety of chimeric antigen receptor T (CAR-T) cell therapy in the treatment of non-Hodgkin's lymphoma has already been demonstrated. However, patients with a history of/active secondary central nervous system (CNS) lymphoma were excluded from the licensing trials conducted on two widely used CAR-T cell products, Axicabtagene ciloleucel (Axi-cel) and Tisagenlecleucel (Tisa-cel). Hence, the objective of the present review was to assess whether secondary CNS lymphoma patients would derive a benefit from Axi-cel or Tisa-cel therapy, while maintaining controllable safety.

Method

Two reviewers searched PubMed, Embase, Web of Science, and Cochrane library independently in order to identify all records associated with Axi-cel and Tisa-cel published prior to February 15, 2021. Studies that included secondary CNS lymphoma patients treated with Axi-cel and Tisa-cel and reported or could be inferred efficacy and safety endpoints of secondary CNS lymphoma patients were included. A tool designed specifically to evaluate the risk of bias in case series and reports and the ROBINS-I tool applied for cohort studies were used.

Results

Ten studies involving forty-four patients were included. Of these, seven were case reports or series. The other three reports were cohort studies involving twenty-five patients. Current evidence indicates that secondary CNS lymphoma patients could achieve long-term remission following Axi-cel and Tisa-cel treatment. Compared with the non-CNS cohort, however, progression-free survival and overall survival tended to be shorter. This was possibly due to the relatively small size of the CNS cohort. The incidence and grades of adverse effects in secondary CNS lymphoma patients resembled those in the non-CNS cohort. No incidences of CAR-T cell-related deaths were reported. Nevertheless, the small sample size introduced a high risk of bias and prevented the identification of specific patients who could benefit more from CAR-T cell therapy.

Conclusion

Secondary CNS lymphoma patients could seem to benefit from both Axi-cel and Tisa-cel treatment, with controllable risks. Thus, CAR-T cell therapy has potential as a candidate treatment for lymphoma patients with CNS involvement. Further prospective studies with larger samples and longer follow-up periods are warranted and recommended.

Radiotherapy for Non-Hodgkin Lymphomas

Radiotherapy (RT) plays a diverse and essential role in the contemporary management of non-Hodgkin lymphoma (NHL) and remains the single most powerful monotherapeutic intervention for both aggressive and indolent subtypes. Over the past decade, there have been significant advancements in radiation oncology practice, which have made modern treatments safer and more conformal. Despite this sophistication and evidence supporting a continued role for RT, numerous data suggest that utilization is on the decline. In this review, we discuss the rationale for RT in 4 commonly encountered scenarios: combined modality therapy for limited-stage aggressive NHL, consolidation therapy for advanced-stage aggressive NHL, and the changing roles of salvage RT for relapsed/refractory NHL in an era of new frontiers such as cellular therapies. We also evaluate current strategies to treat indolent histologies. We conclude with perspectives on how RT for the hematological malignancies may continue to evolve.

Hematopoeitic Cell Transplantation and CAR T-Cell Therapy: Complements or Competitors?

Allogeneic hematopoietic cell transplantation (allo-HCT) and chimeric antigen receptor T cell (CAR T) therapy are the main modalities of adoptive cellular immunotherapy that have widely permeated the clinical space. The advent of both technologies revolutionized treatment of many hematologic malignancies, both offering the chance at sustained remissions for patients who would otherwise invariably succumb to their diseases. The understanding and exploitation of the nonspecific alloreactivity of allo-HCT and the graft-versus-tumor effect is contrasted by the genetically engineered precision of CAR T therapy. Historically, those with relapsed and refractory hematologic malignancies have often been considered for allo-HCT, although outcomes vary dramatically and are associated with potential acute and chronic toxicities. Such patients, mainly with B-lymphoid malignancies, may now be offered CAR T therapy. Yet, a lack of prospective data to guide decisions thereafter requires individualized approaches on whether to proceed to allo-HCT or observe. The continued innovations to make CAR T therapy more effective and accessible will continue to alter such approaches, but similar innovations in allo-HCT will likely result in similarly improved clinical outcomes. In this review, we describe the history of the two platforms, dissect the clinical indications emphasizing their intertwining and competitive roles described in trials and practice guidelines, and highlight innovations in which they complement or inform one another.