Background:

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of malignant tumors. Although the R-CHOP regimen significantly improves the prognosis for patients with DLBCL, 40% of cases experience relapse or become refractory. The MINE regimen (Ifosfamide, Mitoxantrone Hydrochloride Liposome, and Etoposide), with or without obinutuzumab, is a viable second-line chemotherapy option for relapsed or refractory DLBCL. However, there is currently limited research on clinical response and peripheral blood stem cell mobilization related to treating relapsed/refractory DLBCL (R/R DLBCL) with this regimen.

Aims:

This study evaluated the clinical response and peripheral blood stem cell mobilization associated with treating R/R DLBCL using the MINE regimen with or without Obinutuzumab as the second-line chemotherapy.

Methods:

We enrolled first-time R/R DLBCL patients from our hospital in China from January 2023 to April 2024. We collected clinical information, overall response rates, and adverse events for all patients. The MINE±obinutuzumab regimen included obinutuzumab (1000 mg), Mitoxantrone Hydrochloride Liposome (20 mg/m²) on day 1 of each cycle, and Ifosfamide (1.33 mg/m²) and Etoposide (65 mg/m²) once daily on days 1 through 3 of each of the first four cycles.

Results:

Twenty-one patients with first-time R/R DLBCL were enrolled, with a median age of 53 years (range 25-65). The male-to-female ratio was 11:10. Based on the Ann Arbor staging system, 81.0% of patients were classified as stage III/IV, and 71.4% had an International Prognostic Index (IPI) score of ≥3. Additionally, 66.7% of patients had at least one extranodal lesion. Elevated levels of lactic dehydrogenase and β2 microglobulin were found in 76.2% and 85.7% of patients, respectively. According to the Hans algorithm, 81.0% of patients were in the non-GCB group, and the median Ki-67 value was 80% (range 50%-90%). Only one patient was CD5 positive, and 57.1% of patients were diagnosed with double-expression lymphoma. Among the cohort, 71.4% of patients exhibited P53 protein expression greater than 50%. Ten cases were primary refractory diseases, and eight patients had early recurrence disease (relapse within one year). All patients completed at least two cycles of the MINE±obinutuzumab regimen. The overall response rate (ORR) was 95.2%, with a complete response rate (CRR) of 38.1% at the end of the second cycle. By the end of treatment, the ORR was 85.7%, and the CRR was 64.5%. After 2 cycles of this regimen, 80.0% of patients successfully collected peripheral blood stem cells, but after four cycles, only 16.7% of patients were successful. The most common adverse events were hematologic toxicities, with 76.2% of patients experiencing grade 3/4 granulocytopenia after two cycles.

Conclusion: The MINE±obinutuzumab regimen demonstrated good response rates and acceptable safety in treating first-time R/R DLBCL patients. For those requiring autologous stem cell transplantation, it is recommended to collect peripheral blood stem cells as soon as possible after two cycles.

Disclosures

No relevant conflicts of interest to declare.

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2024
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