Addition of rituximab to CHOP-like chemotherapy in first line treatment of primary mediastinal B-cell lymphoma

Abstract

Background: The addition of rituximab (R) to CHOP (cyclophosphamide, doxorubicin, vincristine and prednisone) -like therapy has improved survival in primary mediastinal B-cell lymphoma (PMBCL) patients. However, these results were obtained in young low risk patients and a reevaluation in an unselected patient cohort is warranted.

Methods: In this study, we analyzed 80 PMBCL patients treated with a CHOP-based regimen with and without rituximab.

Results: In the non-rituximab cohort 10-year progression free survival (PFS) was 67% and 10-year overall survival (OS) was 72% versus a PFS of 95% and a OS of 92% in the rituximab group, PFS P = 0.001, OS P = 0.023. A subgroup PFS analysis by international prognostic index (IPI) risk revealed that all risk groups benefit from addition of rituximab to induction chemotherapy. In addition, OS probability was higher in the group of non-low risk patients who were treated with rituximab compared to those patients who did not receive rituximab (P = 0.035). In multivariate analysis, only addition of rituximab to induction chemotherapy and reaching complete remission (CR) after first line therapy had a beneficial effect on both PFS and OS, whereas IPI, age, upfront high dose (HD) chemotherapy/autologous blood stem cell transplantation (ABSCT) and rituximab maintenance had no impact on survival.

Conclusions: Our data demonstrate a survival benefit in unselected PMBCL patients treated with CHOP-like induction regimen and additional rituximab independently of the IPI risk score.

Keywords: Cyclophosphamide; Doxorubicin; International prognostic index (IPI); Primary mediastinal B-cell lymphoma (PMBCL); Rituximab; Vincristine and prednisone (CHOP).

Fig. 1

Progression-free survival (PFS, a) and overall survival (OS, b) of all patients treated either with (N = 45) or without (N = 35) rituximab. Median PFS and OS not reached

Fig. 2

Progression-free survival (PFS, a) and overall survival (OS, b) of low and other than low (low-, high-intermediate, and high) risk patients by IPI treated either with (N = 32 and N = 13) or without (N = 18 and N = 13) rituximab. IPI was not available in 4 patients in the no rituximab treatment group. These patients were excluded from the survival analyses. Median PFS and OS not reached. Due to multiple testing (k = 2) a P-value <0.025 is considered as statistically significant

Fig. 3

Progression-free survival (PFS, a) and overall survival (OS, b) of patients treated with and without consolidation high dose chemotherapy and ABSCT in dependency of rituximab treatment (with rituximab N = 7 and N = 38; without rituximab N = 17 and N = 18). Due to multiple testing (k = 4) a P-value <0.013 is considered as statistically significant

Fig. 4

Progression-free survival (PFS, a) and overall survival (OS, b) of all patients that received rituximab during induction chemotherapy (N = 45) treated either with (N = 24) or without (N = 21) rituximab maintenance therapy. Median PFS and OS not reached