Treatment of Diffuse Large B-Cell Lymphoma with Rituximab, Intensive Induction and High-Dose Consolidation: The Final Analysis of the Czech Lymphoma Study Group (CLSG) R-MegaCHOP-ESHAP-BEAM (R-MEB) Trial.

Background. Combined immunochemotherapy with CHOP and rituximab have improved the outcome of patients with diffuse large B-cell lymphoma (DLBCL). and related diseases. However, the cure rate of patients with IPI 3–5 or aaIPI 3 is still only about 50% with this regimen. Given the feasibility of previous CLSG regimens based on high-dose CHOP-ESHAP induction and BEAM consolidation, we have conducted a phase II trial combining this approach with rituximab immunotherapy.

Patients and methods. Patients aged 18–65 years with DLBCL and age-adjusted IPI (aaIPI) 2–3 were treated with three cycles of high-dose CHOP (MegaCHOP - cyclophosphamide, 3 g/m², vincristine 2 mg, adriamycin, 75 mg/m², and prednisone, 300 mg/m²) with G-CSF every 3 weeks, followed by three cycles of ESHAP (etoposide, 240 mg/m², cisplatin, 100 mg/m², methylprednisolone, 2000 mg and Ara-C 2000 mg/m²) every 3 weeks. Four to six doses of rituximab 375 mg/m² were administered on day 1 of each cycle of induction therapy. High-dose therapy (BEAM) followed by autologous stem cell transplant (ASCT) was used as consolidation. Radiotherapy was given to residual masses or sites of bulky disease. Primary endpoint was progression-free survival (PFS), while secondary endpoints were overall survival (OS) and feasibility of the treatment.

Results. From April 2002 to October 2006, 105 consecutive patients from 10 centers were recruited. 58% were men and 42% women with median age 46 years (19–63 years). 74% of patients had stage IV disease, 92% had elevated LDH, 53% had performance status >1, 55% had B symptoms and 19% had bone marrow involvement. aaIPI was 2 in 62% of patients and 3 in 38% of patients. 68% of patients received the whole treatment according to the protocol, including ASCT and radiotherapy. Stem cells mobilization according to the protocol was performed in 90% of patients and was successful in 86% of mobilized patients (77% of all patients). 73% of patients ultimately received ASCT (including 3 patients transplanted after ammended treatment) and 51% of patients received planned radiotherapy. Complete remission (CR) was achieved in 83% of all patients and partial remission (PR) in 2%. Early toxic death rate was 6% and 9% patients had primary refractory disease. Of patients who achieved CR or PR, only 6 subsequently relapsed (7%) and two suffered late toxic death (2%). With a median follow-up of 32 months for living patients, the estimated 2-year PFS is 77% and 2-year OS is 81%. Age less than median (46 years) was strongest predictor of favorable outcome (p = 0,00006 for PFS and p = 0,00013 for OS), while there was no effect of stage, LDH, performance status or aaIPI (2-year PFS 79% for aaIPI 2 and 77% for aaIPI 3, 2-year OS 81% for aaIPI 2 and 80% for aaIPI 3). Delivery of ASCT or radiotherapy did not significantly affected PFS in patients who did not suffered early progression or early toxic death, but radiotherapy modestly improved OS of these patients (p = 0,03).

Conclusion. R-MEB has proved to be an effective treatment strategy for younger patients with high-risk aggressive B-cell lymphoma. Currently, CLSG is testing whether utilization of early PET scan may decrease toxicity and improve treatment tolerance while maintaining the efficacy of this regimen.