SUMMARY: The American Cancer Society estimates that in 2024, about 80,620 people will be diagnosed with Non Hodgkin Lymphoma (NHL) in the United States and about 20,140 individuals will die of this disease. Diffuse Large B-Cell Lymphoma (DLBCL) is the most common of the aggressive Non-Hodgkin lymphomas in the United States, and more than 25,000 cases of DLBCL are diagnosed each year in the United States, accounting for more than 25 percent of all lymphoma cases. The incidence has steadily increased 3-4% each year. More than half of patients are 65 or older at the time of diagnosis and the incidence is likely to increase with aging of the American population. The etiology of Diffuse Large B-Cell Lymphoma is unknown. Contributing risk factors include immunosuppression (AIDS, transplantation setting, autoimmune diseases), UltraViolet radiation, pesticides, hair dyes, and diet. DLBCL can develop spontaneously or as a result of Richters transformation of low grade diseases such as Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Follicular Lymphoma, or Marginal Zone Lymphoma.
DLBCL is a neoplasm of large B cells and the most common chromosome abnormality involves alterations of the BCL-6 gene at the 3q27 locus, which is critical for germinal center formation. Two major molecular subtypes of DLBCL arising from different genetic mechanisms have been identified, using Gene Expression Profiling: Germinal Center B-cell-like (GCB) and Activated B-Cell-like (ABC). Patients in the GCB subgroup have a higher 5-year survival rate, independent of clinical IPI (International Prognostic Index) risk score, whereas patients in the ABC subgroup have a significantly worse outcome. Regardless of molecular subtype, R-CHOP regimen (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisone), given every 21 days, for 6 cycles, delivered with curative intent, is the current standard of care for patients of all ages, with newly diagnosed DLBCL. Approximately 30-40% of patients experience disease progression or relapse during the first 2 years, and attempts to improve on R-CHOP regimen have not been successful. Maintenance treatment strategy following R-CHOP, to better control the disease, delay disease progression and improve long term survival, have included Autologous Stem Cell Transplantation, CAR T-cell therapy, maintenance treatment with agents such as oral protein kinase inhibitor Enzastaurin and Everolimus. Outcomes for transplant-ineligible patients with Relapsed/Refractory DLBCL patients remain poor. There is a critical unmet need for this patient group.
Brentuximab Vedotin (ADCETRIS®) is an Antibody-Drug Conjugate (ADC) that targets CD30, which is a surface antigen, expressed on Reed-Sternberg cells, in patients with Classical Hodgkin lymphoma. This ADC consists of an anti-CD30 monoclonal antibody linked to MonoMethyl Auristatin E (MMAE), an antimicrotubule agent. Upon binding to the CD30 molecule on the cancer cells, MMAE is released into the cancer cell, resulting in cell death. Preclinical data and early phase studies provided the rationale for combining Brentuximab vedotin, Lenalidomide and Rituximab for the treatment of Relapsed/Refractory DLBCL.
ECHELON-3 is an ongoing, global, randomized, double-blind, multicenter Phase III study, designed to evaluate the efficacy and safety of Brentuximab vedotin in combination with Lenalidomide and Rituximab, compared to Lenalidomide and Rituximab plus placebo, in adult patients with Relapsed/Refractory DLBCL, regardless of CD30 expression, who have received two or more prior lines of therapy and were ineligible for or had previously failed Hematopoietic Stem Cell Transplant (HSCT) or Chimeric Antigen Receptor (CAR) T-cell therapy.
In this global study, 230 patients were randomized 1:1 to receive either Brentuximab vedotin plus Lenalidomide and Rituximab (BV+R2) – N=112, with Brentuximab vedotin administered at 1.2 mg/kg IV every 3 weeks, Lenalidomide at 20 mg orally daily, and Rituximab at 375 mg/m² IV every 3 weeks, or Placebo plus Lenalidomide and Rituximab (placebo+R2) – N=118. Placebo for Brentuximab vedotin with Lenalidomide and Rituximab was administered in the same manner. Treatment continued until disease progression or unacceptable toxicity. The median age was 71 years, 56% were male, median prior lines of therapy was 3, 29% had prior CAR T-cell therapy, approximately 15% of patients had prior bispecific antibody exposure, and 68% were CD30 negative with CD30 tumor expression of less than 1%. The Primary endpoint was Overall Survival (OS). Secondary endpoints included Progression-Free Survival (PFS), Objective Response Rate (ORR) and Complete Response (CR) Rate.
At the interim analysis, with a median follow-up of 16.4 months, BV+R2 regimen demonstrated a median OS of 13.8 months compared to 8.5 months with placebo+R2, representing a 37% reduction in the risk of death (HR=0.63; P=0.0085). The median PFS was 4.2 months in the BV+R2 arm versus 2.6 months in the placebo+R2 arm (HR=0.53; P<0.0001). The ORR was 64.3% with BV+R2 compared to 41.5% with placebo+R2 (P=0.0006). The CR rate was 40.2% with BV+R2 versus 18.6% with placebo+R2. The efficacy benefits of BV+R2 were consistent across key subgroups, including patients with CD30-positive and CD30-negative disease, highlighting the broad applicability of the regimen.
Grade 3 or higher adverse events were more frequent in the BV+R2 arm compared to placebo+R2 (88% versus 77%), and the most common Grade 3 or higher adverse events included neutropenia, anemia and diarrhea. Peripheral Neuropathy was higher with BV+R2 compared to placebo+R2, although generally manageable.
In conclusion, the ECHELON-3 study demonstrated that the addition of Brentuximab vedotin to Lenalidomide and Rituximab significantly improved Overall Survival, Progression-Free Survival, and Response Rates in patients with Relapsed/Refractory DLBCL, compared to Lenalidomide and Rituximab alone. This regimen offers a promising new treatment option for patients who have exhausted standard therapies, or are ineligible for intensive treatments like CAR-T cell therapy or HSCT. The results underscore the potential of targeted therapies in reshaping the management of DLBCL, providing renewed hope for improved outcomes in this challenging disease setting. As the study continues to follow patients for long-term outcomes, ongoing research will further elucidate the durability of responses and additional safety data, thereby informing future clinical practice guidelines and optimizing patient care strategies.
Brentuximab vedotin in combination with lenalidomide and rituximab in patients with relapsed/refractory diffuse large B-cell lymphoma: Results from the phase 3 ECHELON-3 study. Kim JA, Hahn U, Kim W-S, et al. Journal of Clinical Oncology. Volume 42, Number 17_suppl. https://doi.org/10.1200/JCO.2024.42.17_suppl.LBA7005
