FDG-PET-driven consolidation strategy in diffuse large B-cell lymphoma: final results of a randomized phase 2 study

Area of Science:

• Hematology
• Oncology
• Medical Imaging

Background:

• Autologous stem cell transplantation (ASCT) and dose-dense induction remain debated for high-risk diffuse large B-cell lymphoma (DLBCL).
• Positron emission tomography (PET) response-adapted consolidation strategies require further evaluation in DLBCL.

Purpose of the Study:

• To compare the efficacy of R-ACVBP versus R-CHOP14 induction regimens in high-risk DLBCL patients.
• To evaluate the role of PET-driven consolidation (ASCT or standard immunochemotherapy [SIC]) based on early treatment response.

Main Methods:

• A randomized phase 2 trial involving 211 patients with aaIPI2-aaIPI3 DLBCL.
• Patients received either R-ACVBP or R-CHOP14 induction, followed by PET-guided consolidation (SIC or ASCT).
• PET scans assessed response using international harmonization project (IHP) criteria; change in maximal standardized uptake value (ΔSUVmax) was also explored.

Main Results:

• R-ACVBP showed a trend towards higher complete response (CR) rates (47%) compared to R-CHOP14 (39%), though not statistically significant (P=.076).
• R-CHOP14 was associated with higher PET4 positivity (54% vs 41%), more salvage therapy, and significantly lower 4-year event-free survival (EFS) (31% vs 43%, P<.01).
• ΔSUVmax >70% from baseline to PET4 was strongly associated with improved 4-year progression-free survival (PFS) and overall survival (OS) (84% and 91%, respectively), irrespective of consolidation.

Conclusions:

• R-ACVBP did not demonstrate superiority over R-CHOP14 based on IHP criteria, suggesting limitations in reflecting true disease control.
• PET response, particularly ΔSUVmax, appears to be a robust predictor of outcomes in high-risk DLBCL.
• ΔSUVmax may offer a more precise method for selecting patients who would benefit from intensified consolidation strategies, including ASCT.