Anti-CD19 Chimeric Antigen Receptor T-Cell Therapy for Richter Transformation: An International, Multicenter, Retrospective Study

Updates on the Treatment of Richter's Syndrome, Including Novel Combination Approaches

Richter's syndrome (RS) or transformation of chronic lymphocytic leukemia (CLL) into a more aggressive lymphoma (e.g., diffuse large B cell lymphoma, DLBCL) is a distinct disease that portends an overall poor prognosis and remains a challenge for clinicians to identify and treat effectively. This review of the current literature focuses on the pathology, diagnosis, and management of Richter's syndrome. Clonally related RS has been found to have a worse prognosis than unrelated disease and the genomic profile of DLBCL-RS differs from that of de novo DLBCL. The standard of care therapy for RS has historically been chemoimmunotherapy; consolidative stem cell transplants have a role in improving durability of disease response. Given generally poor response rates to chemotherapy, there have been recent investigations into combination treatments with immune checkpoint inhibitors and small molecule targeted therapies, which have had mixed results. Additional studies are evaluating the use of bispecific antibodies, chimeric antigen receptor T cell therapy, and antibody drug conjugates. RS remains difficult to manage; however, advancements in the understanding of the underlying pathology of transformation and continued investigations into new therapies demonstrate promise for the future.

Comprehensive Review of Early and Late Toxicities in CAR T-Cell Therapy and Bispecific Antibody Treatments for Hematologic Malignancies

Chimeric antigen receptor T-cell (or CAR-T) therapy and bispecific antibodies (BsAbs) have revolutionized the treatment of hematologic malignancies, offering new options for relapsed or refractory cases. However, these therapies carry risks of early complications, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), and delayed issues like graft-versus-host disease (GVHD), infections, and secondary cancers. Effective management requires early diagnosis using advanced biomarkers and imaging, along with prompt interventions involving immunosuppressants, corticosteroids, and cytokine inhibitors. A multidisciplinary approach is essential, integrating hematologists, oncologists, and infectious disease specialists, with emerging strategies like targeted biologics and personalized medicine showing promise in balancing efficacy with toxicity management. Ongoing research is critical to refine diagnostics and treatments, ensuring that these therapies not only extend survival but also improve patients' quality of life. This review provides critical insights for healthcare professionals to quickly recognize and treat complications of CAR-T and BsAbs therapies. By focusing on early detection through biomarkers and imaging and outlining timely therapeutic interventions, it aims to equip the multidisciplinary care team with the knowledge necessary to manage the challenges of these advanced treatments effectively, ultimately optimizing patient outcomes.

Updates in the Management of Richter Transformation

Richter transformation (RT) is a rare albeit devastating complication of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL). RT is defined as an aggressive lymphoma, typically diffuse large B-cell lymphoma, in the setting of CLL. A clonal relationship to the preceding CLL clone is detected in the majority of RT cases and confers more aggressive clinicopathologic kinetics, resistance to standard chemoimmunotherapy regimens, and inferior survival. Taken together, these considerations precipitate a significant unmet need for novel therapeutic strategies that improve the outcomes of patients with RT. Through this review, we will explore current data on emerging regimens targeting BTK, BCL-2, CD79, CD20, PI3K, and PD-1-both as single agents and as combination therapies with or without concurrent chemoimmunotherapy. Furthermore, we will review the role of bispecific T-cell engagers, anti-CD19 chimeric antigen receptor T-cell therapies, and hematopoietic stem cell transplantation in RT. To guide therapeutic decision-making, we will outline an algorithmic approach to the management of RT, with particular emphasis on prioritization of clinical trial enrollment and utilization of an ever-evolving array of novel therapies.

Venetoclax Plus Intensified Chemoimmunotherapy as a Bridge to Allogeneic Stem Cell Transplantation in Richter Syndrome: Report of Two Cases

Background: Richter syndrome (RS) represents a major unmet need in the lymphoma field, being refractory to chemoimmunotherapy and targeted agents. The BCL-2 inhibitor venetoclax in combination with dose-adjusted EPOCH-R chemoimmunotherapy showed promising efficacy in patients affected by RS. However, responses were not durable, suggesting the need for further treatment optimization. Methods: Here, we report two cases of RS achieving long-term complete remission with intensified chemoimmunotherapy (Rituximab-G-MALL B-ALL/NHL2002 regimen) plus venetoclax induction, followed by haploidentical hematopoietic stem cell transplant (allo-HSCT). Venetoclax was given continuously for 14 consecutive days after every Rituximab-G-MALL cycle in off-label use. An accelerated venetoclax rump-up schedule was used in both patients to reach the maximal dose. Maximal venetoclax dose was 300 mg and 400 mg in patient 1 and patient 2, respectively. Results: The combined treatment was well tolerated, with no major infective complications or non-hematological toxicities. In both patients, immunosuppression was discontinued within day 180 after transplant with no graft-versus-host-disease flares. Both patients are alive and in continuous complete remission after 60 and 72 months following allo-HSCT. Conclusions: This report supports the feasibility of a combination treatment with BCL-2 inhibitors and intensive chemoimmunotherapy as a bridge to allo-HSCT in RS.

Advances in the understanding of molecular genetics and therapy of Richter transformation in chronic lymphocytic leukemia

Richter's transformation (RT) is defined as the evolution of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) into an aggressive lymphoma, most commonly diffuse large B-cell lymphoma. This complication is rare and aggressive, with poor prognosis and dismal survival. Clonal relationship with the underlying CLL/SLL, observed in ∼80% of cases, represents one of the main factors affecting prognosis. Treatment has been historically based on chemoimmunotherapy, but frequent mutations in genes involved in cell survival and proliferation-such as TP53, NOTCH1, MYC, CDKN2A-confer resistance to standard treatments. During the last years, advances in the knowledge of the biological mechanisms underlying RT allowed to identify genetic and molecular lesions that can potentially be targeted by novel selective agents. Pathway and checkpoint inhibitors, bispecific antibodies and CAR T-cell therapy are currently under investigation and represent promising treatment options. This review summarizes current biological evidence and available data on novel therapeutic agents.

Trogocytosis in CAR immune cell therapy: a key mechanism of tumor immune escape

Immune cell therapy based on chimeric antigen receptor (CAR) technology platform has been greatly developed. The types of CAR immune cell therapy have expanded from T cells to innate immune cells such as NK cells and macrophages, and the diseases treated have expanded from hematological malignancies to non-tumor fields such as infectious diseases and autoimmune diseases. Among them, CAR-T and CAR-NK therapy have observed examples of rapid remission in approved clinical trials, but the efficacy is unstable and plagued by tumor resistance. Trogocytosis is a special phenomenon of intercellular molecular transfer that is common in the immune system and is achieved by recipient cells through acquisition and internalization of donor cell-derived molecules and mediates immune effects. Recently, a novel short-term drug resistance mechanism based on trogocytosis has been proposed, and the bidirectional molecular exchange between CAR immune cells and tumor cells triggered by trogocytosis partially explains the long-term relapse phenomenon after treatment with CAR immune cells. In this review, we summarize the research progress of trogocytosis in CAR immunotherapy, discuss the influencing factors of trogocytosis and its direct and indirect interference with CAR immune cells and emphasize that the interference of trogocytosis can further release the potential of CAR immune cell therapy.

Pharmacological management of chronic lymphocytic leukemia: current and emerging therapies

INTRODUCTION

Chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL), characterized by its monoclonal lymphoproliferative nature, is an indolent but incurable malignancy. The treatment landscape of CLL/SLL has drastically transformed in the last decade since the introduction of targeted therapy and immune-effector T-cell therapy. The paradigm shift from chemoimmunotherapy to targeted and cellular therapies was largely driven by improved efficacy and safety. With the success of targeted therapies, novel agents and combinations are rapidly emerging on the horizon.

AREAS COVERED

In this review, we will summarize clinical evidence supporting current and emerging therapies with emphasis on investigational therapies and novel combinations of commercial agents. Clinical trials were identified via clinicaltrials.gov, and a PubMed literature search was last performed in June 2024.

EXPERT OPINION

With the availability of more effective and better-tolerated treatments for CLL/SLL, the role of early intervention should be further investigated due to its potential to alter disease course, delay progression, and improve overall survival rates. With many highly effective agents and combinations expected to become commercially available, attention to safety profiles and careful selection of patients for each treatment will be critical, with consideration of comorbidities, logistical issues, and financial burden of treatment.

Blinatumomab after R-CHOP bridging therapy for patients with Richter transformation: a phase 2 multicentre trial

Richter transformation (RT) is an aggressive lymphoma occurring in patients with chronic lymphocytic leukaemia. Here we investigated the anti-CD3/anti-CD19 T-cell-engager blinatumomab after R-CHOP (i.e. rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) in patients with untreated RT of diffuse large B-cell lymphoma histology (NCT03931642). In this multicentre phase 2 study, patients without complete response (CR) after two cycles of R-CHOP were eligible to receive an 8-week blinatumomab induction via continuous vein infusion with stepwise dosing until 112 μg/day. The primary endpoint was the CR rate after blinatumomab induction and secondary endpoint included safety, response duration, progression-free and overall survival. Thirty-nine patients started the first cycle of R-CHOP, 25 of whom received blinatumomab. After blinatumomab induction, five (20%) patients achieved CR, four (16%) achieved partial response, and six (24%) were stable. Considering the entire strategy, the overall response rate in the full-analysis-set was 46% (n = 18), with CR in 14 (36%) patients. The most common treatment-emergent adverse events of all grades in the blinatumomab-safety-set included fever (36%), anaemia (24%), and lymphopaenia (24%). Cytokine release syndrome (grade 1/2) was observed in 16% and neurotoxicity in 20% of patients. Blinatumomab demonstrated encouraging anti-tumour activity (the trial met its primary endpoint) and acceptable toxicity in patients with RT.

Are we closer to a standard of care for Richter's syndrome? Novel treatments on the horizon

INTRODUCTION

The therapeutic landscape for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has significantly evolved over the past decade with dramatically improved outcomes with the introduction of targeted therapies. This unfortunately has not been the case for Richter transformation (RT), the histologic transformation to a more aggressive lymphoma, most typically diffuse large B-cell lymphoma (DLBCL). As such, RT continues to be one of the most challenging complications of CLL/SLL. Historically, RT has a poor response to treatment, with a minority reaching complete remission (CR) and overall survival (OS) being less than a year.

AREAS COVERED

The focus of this review is to discuss the effectiveness of commonly used regimens, and review existing data for emerging regimens being examined in ongoing clinical trials to improve prognosis and outcomes in patients with RT. Despite extensive efforts to optimize therapies for RT, there is still no generalized consensus on either first-line treatment regimens or regimens in the relapsed/refractory setting. RT continues to carry a high mortality rate without durable response to current therapeutic agents.

EXPERT OPINION

Ongoing and future research may identify novel treatment approaches that will eventually improve outcomes for patients with RT. The optimal care for RT patients is a clinical trial, when feasible.