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

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.

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.

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.