Combining Obinutuzumab With Radiation for Refractory DLBCL: Retrospective Safety and Efficacy Analysis

Area of Science:

• Hematology
• Oncology
• Radiation Oncology

Background:

• Approximately 30% of diffuse large B cell lymphoma (DLBCL) patients experience relapsed or refractory disease post-chemotherapy.
• Limited treatment options exist for DLBCL patients ineligible for aggressive therapies like stem cell transplant or CAR T-cell therapy.

Purpose of the Study:

• To investigate the safety and efficacy of combining obinutuzumab with cytoreductive radiation for relapsed DLBCL.
• To evaluate this combination in patients with refractory disease who have exhausted other treatment avenues.

Main Methods:

• Retrospective review of 7 patients with refractory DLBCL treated between 2016 and 2022.
• Treatment involved external beam radiation to all disease sites with concurrent and adjuvant obinutuzumab.
• Safety assessed using Common Terminology Criteria for Adverse Events v5.0; efficacy evaluated by progression-free survival (PFS) and overall survival (OS) using Kaplan-Meier analysis.

Main Results:

• No grade 3 or higher treatment-related toxicity was observed in the 7 patients.
• Four out of 7 patients achieved a complete response at radiated sites on initial post-radiation imaging.
• Median progression-free survival was 30 months, and median overall survival was 30 months.

Conclusions:

• The combination of radiation and obinutuzumab is well-tolerated in treatment-refractory DLBCL patients.
• This combination therapy shows potential for durable disease control and prolonged survival in a subset of patients.
• This approach offers a viable treatment option for refractory DLBCL patients with limited therapeutic alternatives.