Tarik Kanouni

Granulocyte-macrophage colony-stimulating factor potentiates rituximab in patients with relapsed follicular lymphoma: results of a phase II study.

PURPOSE We hypothesized that granulocyte-macrophage colony-stimulating factor (GM-CSF) could potentiate the clinical activity of rituximab given its individual and cooperative effects on Fc gamma RIIa- and Fc gamma RIIIa-expressing cells. A phase II clinical study combining GM-CSF and rituximab was initiated in patients with relapsed follicular lymphoma (FL) to determine the clinical and biologic responses, as well as safety of the combination. PATIENTS AND METHODS Thirty three patients with relapsed FL were treated with GM-CSF 5 microg/kg/d on days 1 to 8 and rituximab 375 mg/m(2) on day 5 of each 21-day cycle for four cycles. Clinical response and tolerability were examined according to international criteria. Biologic monitoring included evaluation of immune cells involved in rituximab activity. RESULTS Of 33 evaluated patients, a 70% overall response rate (complete response plus complete response unconfirmed, 45%) and a median progression-free survival (PFS) of 16.5 months were achieved. Outcome was influenced by the quality of response and the Follicular Lymphoma International Prognostic Index (FLIPI), where low- and intermediate-risk FLIPI groups were associated with significantly better PFS. After treatment there was a significant increase in granulocyte and monocyte counts. Examination of dendritic cell response showed an overall increase in plasmacytoid dendritic cells, especially in non-complete response patients, after treatment. Addition of GM-CSF did not impair tolerance to rituximab, and adverse events were rare and mild. DISCUSSION GM-CSF plus rituximab results in high response rates, along with a tolerable safety profile in patients with relapsed or progressive FL. The improved efficacy over rituximab monotherapy may be due to increases seen in monocyte, granulocyte, and dendritic cell populations.

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.

Summary: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 μg/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.

Increased Plasma-Immune Cytokines throughout the High-Dose Melphalan-Induced Lymphodepletion in Patients with Multiple Myeloma: A Window for Adoptive Immunotherapy

High-dose melphalan (HDM) followed by autologous stem cell transplantation (ASCT) is a standard treatment for patients with multiple myeloma. However, lymphocyte reconstitution is impaired after HDM. Recent work has suggested that the lymphopenia period occurring after various immunosuppressive or chemotherapy treatments may provide an interesting opportunity for adoptive antitumor immunotherapy. The objective of this study was to determine an immunotherapy window after HDM and ASCT, evaluating T cell lymphopenia, and measuring circulating immune cytokine concentrations in patients with multiple myeloma. The counts of T cell subpopulations reached a nadir at day 8 post-ASCT (day 10 post-HDM) and recovered by day 30. IL-6, IL-7, and IL-15 plasma levels increased on a median day 8 post-ASCT, respectively, 35-fold, 8-fold, and 10-fold compared with pre-HDM levels (p ≤ 0.05). The increases in IL-7 and IL-15 levels were inversely correlated to the absolute lymphocyte count, unlike monocyte or myeloid counts. Furthermore, we have shown that CD3 T cells present in the ASC graft are activated, die rapidly when they are cultured without cytokine in vitro, and that addition of IL-7 or IL-15 could induce their survival and proliferation. In conclusion, the early lymphodepletion period, occurring 4–11 d post-HDM and ASCT, is associated with an increase of circulating immune cytokines and could be an optimal window to enhance the survival and proliferation of polyclonal T cells present in the ASC autograft and also of specific antimyeloma T cells previously expanded in vitro.

Controlled Epstein–Barr virus reactivation after allogeneic transplantation is associated with improved survival

Epstein–Barr virus reactivation (EBV‐R) frequently occurs in patients having allogeneic hematopoietic stem cell transplantation (HSCT). We evaluated the impact of controlled EBV‐R on survival of 190 patients (114M/76F, median age: 51 yr, range 18–69), having HSCT for hematological malignancies (105 acute leukemias and myelodysplasias, 71 lymphoproliferative disorders, 14 others). Overall survival (OS) and progression‐free survival (PFS) were compared between patients with and without EBV‐R. Of 138, patients had reduced‐intensity conditioning regimen. Various stem cell sources (141 PB, 33 umbilical cord blood and 16 bone marrow) were used. Patients with EBV‐R had longer PFS and OS than those without EBV‐R: PFS at 2 yr 69% vs. 51% and at 5 yr 47% vs. 38% (P < 0.04); OS at 2 yr 76% vs. 64% and at 5 yr 63% vs. 47%) (P < 0.001). The use of rituximab had no impact on OS and PFS, but it reduced the intensity of GVHD, despite the fact that TRM was not significantly different between the two groups of patients. So, rituximab may have an additional effect to other factors on PFS and OS. In multivariate analysis, antithymocyte globulin administration was not a significant factor for PFS (P = 0.68) and for OS (P = 0.81). Circulating NK cells were significantly increased by 22% (P = 0.03) in EBV‐R patients with no differences for other parameters. Controlled EBV‐R in the setting of HSCT is associated with better OS and PFS, with a significant increase in circulating NK cells.

Mobilization of plasma cells in healthy individuals treated with granulocyte colony-stimulating factor for haematopoietic stem cell collection

In mice, the plasma cell (PC) niche in the bone marrow is close to the haematopoietic stem cell (HSC) niche. We investigated whether PCs can be mobilized into the peripheral blood (PB) in healthy donors receiving granulocyte colony‐stimulating factor (G‐CSF) for the induction of HSC mobilization into the PB. G‐CSF increased the count of circulating PCs 6‐fold, that of circulating B lymphocytes 4‐fold and that of circulating HSCs 44‐fold. Mobilized circulating PCs comprised CD138− (62·2%) and CD138+ (37·8%) PCs, the latter being more mature based on increased CD27, CD38 and cytoplasmic immunoglobulin expression. Mobilized PCs had a phenotype close to that of steady‐state PB PCs or in vitro generated PCs, but they expressed L‐selectin only weakly. Finally, a median value of 0·4 × 106/kg donor PCs – one‐thirtieth of the overall PC count in a healthy adult – was grafted into patients, which could contribute to immune memory recovery.

Factors influencing extramedullary relapse after allogeneic transplantation for multiple myeloma

Factors influencing extramedullary relapse after allogeneic transplantation for multiple myeloma

Preemptive rituximab prevents long-term relapses in immune-mediated thrombotic thrombocytopenic purpura

Preemptive rituximab infusions prevent relapses in immune thrombotic thrombocytopenic purpura (iTTP) by maintaining normal ADAMTS13 activity. However, the long-term outcome of these patients and the potential adverse events of this strategy need to be determined. We report the long-term outcome of 92 patients with iTTP in clinical remission who received preemptive rituximab after identification of severe ADAMTS13 deficiency (activity <10%) during the follow-up. Thirty-seven patients had >1 iTTP episode, and the median cumulative relapse incidence before preemptive rituximab was 0.33 episode per year (interquartile range [IQR], 0.23-0.66). After preemptive rituximab, the median cumulative relapse incidence in the whole population decreased to 0 episodes per year (IQR, 0-1.32; P < .001). After preemptive rituximab, ADAMTS13 activity recovery was sustained in 34 patients (37%) during a follow-up of 31.5 months (IQR, 18-65), and severe ADAMTS13 deficiency recurred in 45 patients (49%) after the initial improvement. ADAMTS13 activity usually improved with additional courses of preemptive rituximab. In 13 patients (14%), ADAMTS13 activity remained undetectable after the first rituximab course, but retreatment was efficient in 6 of 10 cases. In total, 14 patients (15%) clinically relapsed, and 19 patients (20.7%) experienced benign adverse effects. Preemptive rituximab treatment was associated with a change in ADAMTS13 conformation in respondent patients. Finally, in the group of 23 historical patients with iTTP and persistently undetectable ADAMTS13 activity, 74% clinically relapsed after a 7-year follow-up (IQR, 5-11). In conclusion, persistently undetectable ADAMTS13 activity in iTTP during remission is associated with a higher relapse rate. Preemptive rituximab reduces clinical relapses by maintaining a detectable ADAMTS13 activity with an advantageous risk-benefit balance.