Establishment of early donor engraftment after reduced-intensity allogeneic hematopoietic stem cell transplantation to potentiate the graft-versus-lymphoma effect against refractory lymphomas

AbstractReduced-intensity allogeneic hematopoietic stem cell transplantation (alloHSCT), which typically results in mixed chimerism initially after transplantation, has had limited efficacy in chemotherapy-refractory lymphomas. We hypothesized that the rapid establishment of complete donor chimerism would potentiate a graft-versus-lymphoma effect. Fifteen patients with chemotherapy-refractory lymphoma initially received induction with a conventional chemotherapy regimen (etoposide, prednisone, vincristine, cyclophosphamide, adriamycin, fludarabine [EPOCH-F]) to deplete host T cells and provide disease control prior to alloHSCT. Patients then received conditioning with fludarabine and cyclophosphamide followed by alloHSCT from HLA-matched siblings. Graft-versus-host disease prophylaxis consisted of cyclosporine alone. EPOCH-F resulted in 73% of patients having partial responses or stable disease. EPOCH-F depleted host CD4+ T cells from a median of 235 cells/μL to 56 cells/μL. Fourteen patients underwent alloHSCT, and all had >95% donor engraftment by day 14 after transplantation. The incidence of Grade II to III acute graft-versus-host disease was 71%. There were two therapy-related deaths. There were 8 partial responses and 3 complete responses (CRs) at day 28. Five additional CRs were observed at day 100 without withdrawal of cyclosporine or donor lymphocyte infusion. The rate of CRs for all 15 patients was 60%. The 1-year progression-free survival rate from time of study entry is 67% with only 1 relapse among 9 CRs. At a median potential follow-up of 28 months, the overall survival rate is 53%. These data demonstrate that a potent and durable graft-versus-lymphoma effect can occur against chemotherapy-refractory lymphomas and suggest that this effect may be associated with rapid, complete donor chimerism after reduced-intensity alloHSCT. © 2003 American Society for Blood and Marrow TransplantationBiology of Blood and Marrow Transplantation 9:162-169 (2003

Coopération entre des bactéries solubilisatrices de phosphate et le champignon mycorhizien à arbuscule Rhizophagus irregularis dans la nutrition phosphatée de la pomme de terre

National audienceLe phosphore est un élément essentiel pour le développement des plantes. Néanmoins, la majorité des ions phosphate est incorporée dans des structures organiques (Po) et inorganiques (Pi) insolubles qui rende cet élément très peu disponible pour les plantes et en particulier pour la pomme de terre (Solanum tuberosum). Dans les sols, le phytate (molécule de réserve phosphatée des plantes), est une source essentielle. Pour accéder au phosphate, les plantes ont développé des symbioses mutualistes à bénéfices réciproques avec des microorganismes de la rhizosphère capables d’extraire le P. Dans ce contexte, les objectifs de cette étude étaient de i) déterminer si la disponibilité en P du sol impacte la distribution des communautés bactériennes efficaces pour mobiliser le P et ii) développer des associations contrôlées tripartites entre plante/champignon mycorhizien et souche bactérienne efficace pour mobiliser le P. Un total de 185 souches bactériennes provenant de trois sols caractérisés par des concentrations en phosphate total différentes ont été caractérisées sur leur capacité à rompre des complexes de Po (phytate) et de Pi (Tricalcique phosphate) ainsi à acidifier. Cette étude a révélé que la concentration en phosphate libre d’un sol affecte la fréquence et l’efficacité des communautés bactériennes capables de dégrader le phytate. La souche bactérienne 11.2B affiliée au genre Erwinia est apparue comme la plus efficace dans cette fonction de solubilisation. La comparaison des résultats issus des différents biotests suggère que la solubilisation du phytate dans nos collections serait essentiellement due à une acidification, plutôt qu’à une activité phytase strictement. Un protocole expérimental visant à associer S. tuberosum, le champignon mycorhizien à arbuscule Rhizophagus irregularis et la souche 11.2B a été développé in vitro. Ce modèle expérimental a pour but d’analyser in fine l’impact de ces deux microorganismes symbiotiques sur la nutrition phosphatée du plant de pomme de terre

Utility Of An Algorithm For Use Of Plerixafor In Filgrastim-based Hematopoietic Progenitor Cell Mobilization In Patients With Plasma Cell Myeloma Treated With Carfilzomib-Lenalidomide-Dexamethasone

Abstract Mobilization of hematopoietic progenitor cells (HPC) for subsequent autologous transplantation is difficult in patients with plasma cell myeloma (PCM) due to poor marrow reserve. Targeted HPC yields are generally not achieved in a single apheresis procedure without use of plerixafor as a supplement to standard filgrastim. Strategies to limit use of plerixafor, due to its expense, to cases of poor CD34 mobilization have been developed, but their applicability in patients receiving the novel induction regimen carfilzomib-lenalidomide-dexamethasone (CRD) (Blood 2012;120:1801) has not been described. We prospectively studied the CD34 cell mobilization responses of PCM patients following CRD induction, using a CD34 cell predictive algorithm to determine when plerixafor should be added to the mobilization regimen. Thirty patients, including 23 with PCM and 7 with smoldering PCM, mean age 55 (range 40-72), 47% male, received 4 to 7 cycles of CRD (median, 5 cycles), with the last dose of lenalidomide given at least one week prior to mobilization. Filgrastim 10-16 mcg/kg/day was given as a single evening dose for 5 days, with circulating CD34 count assessed 12 hours after the 4th dose. The pre-apheresis CD34 count after the 5th dose of filgrastim was predicted to be 10% greater than that after the 4th dose; this prediction was validated with an actual pre-apheresis CD34 count obtained the following day. Prior mobilization data derived from healthy HPC apheresis donors was used to generate a regression formula, y=0.45x+0.86, where x=the pre-apheresis circulating CD34 count after the 5th dose of filgrastim, and y=the expected yield of the apheresis procedure, expressed as millions of CD34 cells harvested per liter processed. Targeted yield was ≥ 4 x 106 CD34 cells/kg, with minimum acceptable yield ≥ 2 x 106 CD34 cells/kg. Plerixafor 240 mcg/kg was given with the 5th dose of filgrastim, 8-10 hours prior to apheresis, if the regression equation predicted a CD34 cell yield of < 4 x 106 CD34 cells/kg in a single procedure with a maximum of 30 liters processed. The actual volume processed was based on the stat blood CD34 count drawn immediately prior to apheresis. Procedures were performed on the Cobe Spectra device; continuous intravenous calcium was used to mitigate citrate toxicity. Central lines were required in 67% of subjects. Mean CD34 cell count in the entire group after the 4th dose of filgrastim was 29/uL (range 2-88/uL). Using the regression formula as a guide, 17/30 (57%) of patients received plerixafor. CD34 counts increased 4.2-fold in patients receiving plerixafor, from 15 ± 9/uL (m ± SD) on the day prior to apheresis to 53 ± 30/uL immediately pre-apheresis; CD34 counts did not change in patients who received filgrastim alone (from 48 ± 17/uL to 45 ± 19/uL). Guided by the stat pre-apheresis CD34 count, the volume processed in the first apheresis procedure was the same, 23 ± 7 (range 12-30) liters, with or without plerixafor. CD34 cells were collected with 72 ± 14% efficiency. First-procedure CD34 cell yields were 6.4 ± 2.5 x 106/kg (range 2.5-10.1) with supplemental plerixafor vs 5.8 ± 2.5 x 106/kg (range 1.1-9.3) with filgrastim alone. Only 2/30 patients underwent a second procedure; neither received plerixafor prior to the first procedure, and both received it prior to the second. In one patient, criteria for plerixafor administration were met, but the drug was inadvertently not given prior to the first procedure; in the second patient, an unexpectedly low pre-apheresis CD34 count was traced to inadequate self-administration of the 5th dose of filgrastim. All 30 patients achieved the minimum CD34 collection goal of ≥ 2 x 106 cells/kg and 29/30 did this in one procedure. The higher targeted collection goal of ≥ 4 x 106 CD34 cells/kg was achieved in a single procedure by 76% of patients in both the plerixafor group and the filgrastim-alone group. There was a trend for higher cumulative lenalidomide and carfilzomib doses to be associated with lower CD34 mobilization responses to filgrastim. Induction treatment with CRD does not appear to impair HPC mobilization response to filgrastim in patients with PCM, compared to older regimens. An algorithm that uses the CD34 cell count after 4 doses of filgrastim to predict the following day’s pre-apheresis CD34 count and thus determine whether plerixafor supplementation is needed, was useful in identifying the 40% of CRD-treated myeloma patients who do not need plerixafor. Disclosures: No relevant conflicts of interest to declare

Carfilzomib and Bortezomib Containing Regimens Yield High Rates Of MRD Negative Autologous Hematopoietic Progenitor Cell (HPC) Grafts In Multiple Myeloma (MM) and High Risk Smoldering Myeloma (SMM)

Abstract Background Regimens incorporating modern anti-myeloma drugs, such as carfilzomib (CFZ) and bortezomib (BOR), produce rapid, deep and durable responses in newly diagnosed myeloma patients but their effect on collection of autologous HPC is not well known, including minimal residual disease (MRD) testing of stem cell grafts. Employing older induction regimens (such as VAD), less sensitive flow cytometry techniques detected circulating myeloma cells in 38-46% of autologous HPC grafts (Stewart, et al. JCO. 2001 and Bourhis, et al. Haematologica. 2007). We hypothesized that the use of modern CRd combination therapy including Carfilzomib (CFZ)-Lenalidomide (LEN)-Dexamethasone (DEX) would significantly lower the rates of HPC product contamination. Methods Thirty-six patients, including 29 with MM and 7 with high-risk SMM, underwent HPC mobilization and collection following induction with CRd (n=30), LEN-BOR-DEX (RVd, n=4), Cyclophosphamide-BOR-DEX (CyBorD, n=1) and Cyclophosphamide-BOR-Prednisone (CyBorP, n=1). For HPC mobilization, all patients received 5 days of filgrastim at 10-16 mcg/kg/dose. A combination of the patient’s weight and a peripheral blood CD34 count after 4 doses was used to determine the likelihood of collecting > 4 x106 CD34+ cells/ kg in a single apheresis procedure after a fifth filgrastim dose, according to a previously published algorithm from our institution. Only subjects predicted to require > 1 apheresis by the algorithm received Plerixafor (PLX) at 240 mcg/kg/dose on the fifth day along with the fifth filgrastim dose. HPC collection occurred on day 6, 8 hours after the last mobilizing agent(s) administration. Product contamination with myeloma cells (i.e. MRD status) was evaluated using multi-parameter flow cytometry with a minimum of 3 x 106 events obtained (sensitivity detection rate 1 x 10-5) to examine expression of 9 antigens by the plasma cells. Results The median age at mobilization was 56.2 years (range 40-73) and 19 (53%) were male. At the time of HPC collection, 20 (55%) patients were in sCR/CR/nCR, 11 (30%) had VGPR with 4 PR (11%) and 1 SD (3%). The mean CD34+ cells in the peripheral blood were 33/uL on day 5 and 55/uL on day 6 for the whole cohort. Thirteen (36%) patients did not need PLX. Interestingly, the mean CD34+ count dropped by a mean of 2% from D5 to D6 in patients not receiving PLX while, as expected, it increased by 304% in those who did. The median number of CD34+ cells collected was 6.86 million/kg (range 2.6-12.5) for the whole cohort, (6.6 million/kg without PLX and 7.52 million with PLX p=0.46). Thirty-three of 36 patients (92%) achieved a collection of > 4 million cells /kg in a single apheresis procedure. The 30 patients treated with CRd had a median of 5 (range = 3-7) prior cycles containing LEN with a median of 12 days (range 1-34) between mobilization and last LEN dose. Only 2 of 36 (5%) products were found to have evidence of tumor cell contamination (i.e. MRD positive) using sensitive multiparameter flow cytometry, one patient in PR after 6 cycles of CRd and a second patient in CR after 5 cycles of RVd. Conclusions Modern anti-myeloma therapies, such as CRd and RVd, allow adequate HPC collection in a single apheresis procedure in most cases and improve the quality of the HPC product with greatly reduced tumor cell contamination compared to historical controls. Indeed, 34/36 (94%) patients treated with modern anti-myeloma therapy collected an MRD negative HPC product. Future prospective studies are needed to assess whether autologous stem cell transplants (ASCT) using tumor-free HPC products collected in the era of modern induction therapies have better outcomes. Disclosures: No relevant conflicts of interest to declare