Conditioning regimens for allotransplants for diffuse large B-cell lymphoma: myeloablative or reduced intensity?

Area of Science:

• Hematology
• Oncology
• Transplantation Medicine

Background:

• Allogeneic stem cell transplantation is a potential curative option for high-risk diffuse large B-cell lymphoma (DLBCL).
• The optimal conditioning regimen (myeloablative, reduced intensity, or nonmyeloablative) prior to transplantation for DLBCL is not well-defined.

Purpose of the Study:

• To compare the outcomes of myeloablative (MAC), reduced intensity (RIC), and nonmyeloablative (NMAC) conditioning regimens in patients undergoing allogeneic transplantation for DLBCL.

Main Methods:

• Retrospective analysis of 396 DLBCL patients who received MAC, RIC, or NMAC regimens for allogeneic transplantation.
• Comparison of acute and chronic graft-versus-host disease (GVHD), nonrelapse mortality (NRM), relapse/progression rates, progression-free survival (PFS), and overall survival (OS).

Main Results:

• Similar rates of acute and chronic GVHD across all conditioning groups.
• Higher 5-year NRM in MAC (56%) compared to RIC (47%) and NMAC (36%).
• Lower 5-year relapse/progression in MAC (26%) compared to RIC/NMAC (38%-40%).
• No significant differences in 5-year PFS (15%-25%) or OS (18%-26%) between groups.
• Multivariate analysis identified NMAC and recent transplant year associated with lower NRM; lower Karnofsky score, prior refractory relapse, and unrelated donors associated with higher NRM.
• NMAC, no prior rituximab, and prior refractory relapse associated with increased relapse/progression risk.

Conclusions:

• Allogeneic transplantation with RIC or NMAC regimens offers long-term progression-free survival in selected DLBCL patients.
• RIC/NMAC regimens are associated with reduced nonrelapse mortality but an increased risk of lymphoma progression or relapse compared to MAC.
• Treatment decisions should consider the trade-off between NRM and relapse risk based on patient-specific factors.