Identification of the atypically modified autoantigen Ars2 as the target of B-cell receptors from activated B-cell-type diffuse large B-cell lymphoma.

It has been suggested that B-cell receptor (BCRs) stimulation by specific antigens plays a pathogenic role in diffuse large B-cell lymphoma (DLBCL). Here, it was the aim to screen for specific reactivities of DLBCL-BCRs in the spectrum of autoantigens and antigens of infectious origin. Arsenite resistance protein 2 (Ars2) was identified as the BCR target of 3/5 ABC-type DLBCL cell lines and 2/11 primary DLBCL cases. Compared to controls, Ars2 was hypo-phosphorylated exclusively in cases and cell lines with Ars2-specific BCRs. In a validation cohort, hypo-phosphorylated Ars2 was found in 8/31 ABC-type, but only 1/20 germinal center B cell (GBC)-like type DLBCL. Incubation with Ars2 induced BCR-pathway activation and increased proliferation, while an Ars2/ETA-toxin conjugate induced killing of cell lines with Ars2-reactive BCRs. Ars2 appears to play a role in a subgroup of ABC-type DLBCLs. Moreover, transformed DLBCL lines with Ars2-reactive BCRs still show growth advantage after incubation with Ars2. These results provide knowledge about the pathogenic role of a specific antigen stimulating the BCR pathway in DLCBL.

Age-dependent increase of treatment-related mortality in older patients with aggressive B cell lymphoma: analysis of outcome, treatment feasibility, and toxicity in 1171 elderly patients with aggressive B cell lymphoma-data from phase II and III trials of the DSHNHL (German High-Grade Non-Hodgkin's Lymphoma Study Group).

In elderly patients (pts) with aggressive B cell lymphoma (aNHL), curative treatment often cannot be administered because of comorbidities and tolerability. We analyzed the influence of age in pts > 60 years receiving the R-CHOP-14 regimen within different prospective DSHNHL trials. Of the RICOVER-60 trial and CHOP-R-ESC trials, 1171 aNHL pts were included in this retrospective analysis of age-dependent event-free survival (EFS), progression-free survival (PFS), and overall survival (OS). All patients received prophylactic G-CSF, and anti-infective prophylaxis with amphotericin B mouth wash and oral fluorchinolone was optional. In the CHOP-R-ESC trials, prophylaxis was augmented to include mandatory continuous orally administered aciclovir and a pneumocystis prophylaxis with cotrimoxazole as well as oral fluorchinolones during neutropenia. The patient population was separated into 4 age groups (61-65 years, 66-70 years, 71-75 years, and 76-80 years). The results from the RICOVER-60 trial were subsequently confirmed in the following CHOP-R-ESC trials by a multivariate analysis adjusted for IPI factors and gender. Significant differences (p < 0.001) in EFS, PFS, and OS were seen between age groups (RICOVER-60). Hematotoxicity, infections, and TRM increased with age. TRM was significantly elevated in the age group 76-80 years. Therefore, this analysis shows that an age above 75 years defines an especially vulnerable patient population when being treated with chemoimmunotherapy for aNHL. Prophylactic anti-infective drugs are essential and clinically effective in reducing morbidity when treating elderly aNHL pts.

Optimization of rituximab for the treatment of DLBCL: increasing the dose for elderly male patients.

Male sex is associated with unfavourable pharmacokinetics and prognosis in elderly patients with diffuse large B-cell lymphoma (DLBCL). We investigated higher rituximab doses for elderly male DLBCL patients. Elderly patients (61-80 years) received 6 cycles CHOP-14 (cyclophosphamide, doxorubicin, vincristine and prednisone at 14-day intervals) and were randomized to 8 cycles rituximab (males 500 mg/m2 , females 375 mg/m2 ) every 2 weeks or according to an upfront dose-dense schedule. In 268 (120 females, 148 males) no difference between the standard and the upfront dose-dense rituximab schedule was found (3-year PFS 72% vs. 74%; OS 74% vs. 77%; P = 0.651). The 500 mg/m2 dose of rituximab for male patients was associated with serum levels and exposure times slightly better than in females and a male/female hazard ratio of 0.9 for progression-free survival (PFS) and 0.8 for overall survival. For elderly males, 500 mg/m2 was not more toxic than 375 mg/m2 rituximab, but improved PFS by 32.5% (P = 0.039), with a trend for a (30%) better overall survival (P = 0.076) in a planned subgroup analysis adjusting for International Prognostic Index risk factors. We conclude that the higher rituximab dose for elderly male patients abrogated the adverse prognosis of male sex without increasing toxicity. In the era of personalized medicine, sex-specific pharmacokinetics and toxicities should be investigated for all drugs where these parameters impact on outcome.

Role of radiotherapy to bulky disease in elderly patients with aggressive B-cell lymphoma.

PURPOSE: R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) is standard care for aggressive B-cell lymphoma. A prospective trial was conducted to investigate the role of additive radiotherapy (RT) to bulky and extralymphatic disease. PATIENTS AND METHODS: The best arm of the RICOVER-60 trial (6×R-CHOP-14+2R [R-CHOP administered once every 2 weeks plus two additional applications of rituximab] plus involved-field RT [36 Gy] to sites of initial bulky [≥ 7.5 cm] disease and extralymphatic involvement) was compared with a cohort receiving the same immunochemotherapy but without RT in an amendment to the RICOVER-60 trial (RICOVER-noRTh) in a prospective fashion. RESULTS: After a median observation time of 39 months, 164 of 166 RICOVER-noRTh patients were evaluable. In a multivariable analysis of the intention-to-treat population adjusting for International Prognostic Index risk factors and age (> 70 years), event-free survival (EFS) of patients with bulky disease was inferior without additive RT (hazard ratio [HR], 2.1; 95% CI, 1.3 to 3.5; P = .005), with trends for inferior progression-free (PFS; HR, 1.8; 95% CI, 1.0 to 3.3; P = .058) and overall survival (OS; HR, 1.6; 95% CI, 0.9 to 3.1; P = .127). In a per-protocol analysis with 11 patients in RICOVER-noRTh excluded for receiving unplanned RT, multivariable analysis revealed HRs of 2.7 (95% CI, 1.3 to 5.9; P = .011) for EFS, 4.4 (95% CI, 1.8 to 10.6; P = .001) for PFS, and 4.3 (95% CI, 1.7 to 11.1; P = .002) for OS for patients not receiving RT to bulky disease. CONCLUSION: Additive RT to bulky sites abrogates bulky disease as a risk factor and improves outcome of elderly patients with aggressive B-cell lymphoma. Whether RT can be spared in patients with (metabolic) complete remission after immunochemotherapy must be addressed in appropriately designed prospective trials.

Rituximab for the treatment of diffuse large B-cell lymphomas.

For more than 25 years, the combination of cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) was considered the gold standard for the treatment of aggressive lymphomas, 90% of which are diffuse, large B-cell lymphomas (DLBCLs). Attempts to improve results by more intensive chemotherapy regimens, including high-dose chemotherapy approaches necessitating stem-cell support, have not convincingly shown improved outcome of DLBCL. The chimeric monoclonal antibody rituximab, which binds to the CD20 antigen expressed on normal B cells and the malignant cells of more than 90% of DLBCLs, and mediates lysis of these cells by direct induction of apoptosis, activation of complement- and antibody-dependent cellular cytotoxicity in vitro, is an attractive candidate for the treatment of B-cell lymphomas. Initial studies in follicular lymphoma demonstrated its efficacy as a single agent or in combination with chemotherapy without adding relevant toxicity. After the demonstration of rituximab single-agent activity in DLBCL, a pivotal trial in elderly patients demonstrated that combining rituximab with eight applications of CHOP significantly improved complete remission, event-free and overall survival rates when compared with CHOP alone. These positive results have meanwhile been confirmed by two additional randomized trials in elderly patients and have been extended to young patients with good-prognosis DLBCL by a fourth trial. While not yet formally established in young, poor-prognosis patients, rituximab in combination with CHOP has become accepted worldwide as the new standard for the treatment of DLBCL. Questions remain concerning the optimal dosage and schedule of rituximab for DLBCL, as well as the optimal chemotherapy regimen partner for rituximab. Rituximab is the first monoclonal antibody to consistently improve survival rates of patients with a malignant disease. Its excellent efficacy in combination with cytotoxic chemotherapy, together with its favorable toxicity profile, establishes rituximab as an indispensable component of modern standard immunochemotherapy of DLBCL.