Mosunetuzumab in combination with CHOP in previously untreated DLBCL: safety and efficacy results from a phase 2 study

Bispecific antibodies in the treatment of relapsed/refractory large B-cell lymphoma

INTRODUCTION

The management of relapsed and/or refractory (R/R) large B-cell lymphoma (LBCL) has witnessed dramatic changes in the recent past. Despite the availability of multiple novel immunotherapies in R/R setting, there remains an unmet need for off-the-shelf therapies, particularly in patients with primary refractory, multiply relapsed disease or those experiencing cellular immunotherapy failure. To harness the power of the T-cell mediated immunity, a novel class of drugs called bispecific antibodies (BsAbs) have been developed. These BsAbs are currently under investigation both in frontline and R/R setting and hold the potential to revolutionize the management of LBCL.

AREAS COVERED

This review article summarizes the currently available BsAbs, their mode of action, efficacy, and safety data for untreated and R/R LBCL. In addition, the role of these BsAbs in combination with currently available chemoimmunotherapy regimens is also discussed.

EXPERT OPINION

Two BsAbs have secured FDA approval for R/R LBCL, with expected approval of more BsAbs (including in earlier treatment lines). These drugs provide a highly efficacious and relatively safe treatment option for patients with highly pretreated disease including relapse after cellular immunotherapies. In addition, these BsAbs provide a platform for chemotherapy-free regimen for older/frail patients.

SOHO State of the Art Updates and Next Questions | Current Evidence and Future Directions for Bispecific Antibodies in Large B-Cell Lymphoma

The CD20xCD3 bispecific antibodies (bsAb) are "off-the-shelf" T-cell re-directing therapies that demonstrate remarkable single-agent clinical activity in B-cell lymphomas. Two agents, epcoritamab (epcor) and glofitamab (glofit) have recent global approvals for patients with relapsed/refractory DLBCL (RR DLBCL) following 2 prior treatment lines. Both agents demonstrate activity in patients with prior exposure to chimeric antigen receptor T-cell (CAR-T) treatment. As multiyear follow-up data become available, it is clear that the majority of patients achieving complete remissions do not relapse and that outcomes are similar between epcor and glofit. CD20xCD3 bsAb have a safety profile that reflect their mechanism of action, with cytokine release syndrome (CRS) the key management issue. Neurotoxicity is far less common than observed with CD19-directed CAR-T. BsAbs are attractive, rapidly available, treatment options for patients with RR DLBCL, without the practical and financial challenges seen with autologous CAR-T therapies. Recent data also demonstrate the feasibility and potential efficacy of bsAb in combination with chemoimmunotherapy with large randomized trials evaluating bsAb-chemotherapy combinations underway. There are open questions about the future role of bsAB for LBCL, the optimal duration of therapy, optimal CRS risk mitigation strategies, and potential resistance mechanisms. In this review we seek to describe the current evidence for bsAb in LBCL, and offer opinion regarding these open questions.

New Insights into First-Line Therapy in Diffuse Large B-Cell Lymphoma: Are We Improving Outcomes?

Diffuse large B-cell lymphoma (DLBCL) is the most prevalent subtype of lymphoma, comprising heterogeneous patient subgroups with distinctive biological and clinical characteristics. The R-CHOP combination (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) has been the standard initial treatment, yielding prolonged remissions in over 60% of patients with advanced-stage disease. Several attempts to enhance the outcomes of this regimen over the last two decades have shown limited success. Various novel therapeutic approaches have recently emerged in lymphoma, demonstrating promising results. These include small molecules, novel monoclonal antibodies, antibody-drug conjugates (ADC), bispecific antibodies (BsAbs), and chimeric antigen receptor (CAR) T-cell therapy. This review explores recent advancements in therapeutic strategies for DLBCL and their potential impact on the initial management of DLBCL patients.

Bispecific antibodies and CAR-T cells: dueling immunotherapies for large B-cell lymphomas

Despite recent advances in frontline therapy for diffuse large B-cell lymphoma (DLBCL), at least a third of those diagnosed still will require second or further lines for relapsed or refractory (rel/ref) disease. A small minority of these can be cured with standard chemoimmunotherapy/stem-cell transplant salvage approaches. CD19-directed chimeric antigen receptor T-cell (CAR-19) therapies are increasingly altering the prognostic landscape for rel/ref patients with DLBCL and related aggressive B-cell non-Hodgkin lymphomas. Long-term follow up data show ongoing disease-free outcomes consistent with cure in 30-40% after CAR-19, including high-risk patients primary refractory to or relapsing within 1 year of frontline treatment. This has made CAR-19 a preferred option for these difficult-to-treat populations. Widespread adoption, however, remains challenged by logistical and patient-related hurdles, including a requirement for certified tertiary care centers concentrated in urban centers, production times of at least 3-4 weeks, and high per-patients costs similar to allogeneic bone-marrow transplantation. Bispecific antibodies (BsAbs) are molecular biotherapies designed to bind and activate effector T-cells and drive them to B-cell antigens, leading to a similar cellular-dependent cytotoxicity as CAR-19. May and June of 2023 saw initial approvals of next-generation BsAbs glofitamab and epcoritamab in DLBCL as third or higher-line therapy, or for patients ineligible for CAR-19. BsAbs have similar spectrum but generally reduced severity of immune related side effects as CAR-19 and can be administered in community settings without need to manufacture patient-specific cellular products. To date and in contrast to CAR-19, however, there is no convincing evidence of cure after BsAbs monotherapy, though follow up is limited. The role of BsAbs in DLBCL treatment is rapidly evolving with trials investigating use in both relapsed and frontline curative-intent combinations. The future of DLBCL treatment is bound increasingly to include effector cell mediated immunotherapies, but further optimization of both cellular and BsAb approaches is needed.