Optimizing the use of anti-interleukin-6 monoclonal antibody with dexamethasone and 140 mg/m2 of melphalan in multiple myeloma: results of a pilot study including biological aspects.

Interleukin-6 (IL-6) is a major survival factor for multiple myeloma (MM) cells preventing apoptosis induced by dexamethasone (DEX) or chemotherapy. In all, 24 consecutive patients with MM in first-line therapy received DEX for 4 days, followed by melphalan (HDM: 140 mg/m2) and autologous stem cell transplantation (ASCT). The anti-IL-6 monoclonal antibody (mAb) (B-E8) was given till haematological recovery, starting 1 day before DEX. Results were historically compared to MM patients treated with HDM 140 and 200 mg/m2. Our results show (1) that B-E8 was able to fully neutralize IL-6 activity in vivo before and after HDM as shown by inhibition of C reactive protein (CRP) production; (2) no haematological toxicity; (3) a significant reduction of mucositis and fever; (4) a median event-free survival of 35 months and an overall survival of 68.2% at 5 years with a median follow-up of 72 months; and (5) the overall daily IL-6 production progressively increased on and after 7 days post-HDM, with the increased serum CRP levels. In the 5/24 patients with uncontrolled CRP production, a large IL-6 production was detected (320 microg/day) that could not possibly be neutralized by B-E8. These data show the feasibility to neutralize IL-6 in vivo with anti-IL-6 mAb in the context of HDM.

Treatment of acute graft-versus-host disease with methylprednisolone and cyclosporine with or without an anti-interleukin-2 receptor monoclonal antibody. A multicenter phase III study.

A double-blind, placebo-controlled trial of BT563, including 13 European centers, was initiated in October 1989 to compare the efficacy of the combination of in vivo anti-CD25 mAb (BT 563), cyclosporine, and steroids versus placebo and CSA-steroids in the treatment of grade II and III acute graft-versus-host disease (GVHD). Sixty-nine patients participated in the study, which excluded non-genotypically identical allogeneic bone marrow transplant recipients. No statistically significant differences were observed, clinically or biologically, between the 2 groups before the onset of the treatment. Treatment responses were scored during and after the 3-week treatment period (mAb or placebo). Efficacy was evaluated on days 4, 10, 20, 30, and 60 or on any day the patient's condition was found to be deteriorating. Preceding and systemically untreated GVHD of grade I was observed in 59% of the cases. No statistically clinically significant differences between the 2 groups were observed during or upon completion of treatment in GVHD grade. Nine patients in the placebo group and 6 in the active group were withdrawn of the study. Thirteen of these 15 patients were withdrawn because of failure of GVHD therapy (9 in the placebo group and 4 in the BT563 group). At day 20 after onset of the treatment, the response rate was 63% and 70% for the placebo and BT563 groups, respectively (NS). Probability of survival at 1 year was 59% and 66% (NS) for the placebo and active groups, respectively. In conclusion, despite preliminary promising results in the treatment of steroid-resistant acute GVHD, the role of first-line treatment with an in vivo anti-interleukin-2 receptor mAb remains to be determined.

Interleukin-6 dependence of advanced malignant plasma cell dyscrasias.

The authors, and others, clearly have established that interleukin-6 (IL-6) is the major growth factor for human myeloma cells in vitro. It is a critical conceptual point whether or not IL-6 remains involved in the final phases of disease progression in malignant plasma cell dyscrasias. To answer this question, the authors evaluated the in vitro IL-6 dependence of the proliferation of myeloma cells from the bone marrow of 13 patients with advanced multiple myeloma (MM) and from the peripheral blood of 13 patients with plasma cell leukemia (seven primary and six secondary cases). Their results show that myeloma cell growth was totally dependent on IL-6 in 25 of 26 patients. Myeloma cells of only one patient did not respond to IL-6 in vitro. Actually, the cells from this patient were not proliferating in vivo. Identical patterns of IL-6 dependence of myeloma cells were found in the peripheral blood and bone marrow from four patients with PCL. The authors conclude that, in the terminal phase of malignant plasma cell dyscrasias, tumoral growth is totally dependent on IL-6 in vitro. This observation is critical in considering the investigation of anti-IL-6 therapy in patients with advanced MM.

CD99 (E2) up-regulates alpha4beta1-dependent T cell adhesion to inflamed vascular endothelium under flow conditions.

CD99/E2 is an integral transmembrane protein which forms, together with Xga, a distinct family whose genes are located in the pseudoautosomal region. The number of T cells that firmly bound to vascular endothelial cells under physiological shear stress increased 2-14-fold upon CD99 stimulation, and bound cells became much more resistant to detachment forces and spread. T cell arrest occurred within 1 min and was dependent on the alpha4beta1-VCAM-1 pathway. In contrast, the alphaLbeta2-ICAM-1 pathway remained unactivated. This was observed with T cell lines and with activated peripheral blood lymphocytes, and was limited within the resting peripheral CD4+ T cells to the memory subset, while virgin cells were unaffected. This discloses a stepwise regulation of the T cell extravasation cascade.