Long-term survival of sorafenib-treated FLT3-ITD-positive acute myeloid leukaemia patients relapsing after allogeneic stem cell transplantation.

BACKGROUND: Fms-like tyrosine kinase 3 internal tandem duplication (FLT3-ITD)-positive acute myeloid leukaemia (AML) relapsing after allogeneic stem cell transplantation (allo-SCT) has a dismal prognosis with limited therapeutic options. FLT3-ITD kinase inhibition is a reasonable but palliative experimental treatment alternative in this situation. Information on long-term outcome is not available. METHODS: We performed a long-term follow-up analysis of a previously reported cohort of 29 FLT3-ITD-positive AML patients, which were treated in relapse after allo-SCT with sorafenib monotherapy. FINDINGS: With a median follow-up of 7.5 years, 6 of 29 patients (21%) are still alive. Excluding one patient who received a second allo-SCT, five patients (17%) achieved sustained complete remissions with sorafenib. Four of these patients are in treatment-free remission for a median of 4.4 years. INTERPRETATION: Sorafenib may enable cure of a proportion of very poor risk FLT3-ITD-positive AML relapsing after allo-SCT.

Antithymocyte globulin for the prevention of graft-versus-host disease after unrelated hematopoietic stem cell transplantation for acute myeloid leukemia: results from the multicenter German cooperative study group.

A total of 155 patients with acute myeloid leukemia (AML) received hematopoietic stem cell transplants from unrelated donors after standard conditioning. Clinical outcome after the use of two different antithymocyte globulins for the prevention of graft-versus-host disease (GvHD) was analyzed in a retrospective study as follows: rabbit ATG (Thymoglobulin Sangstat/Genzyme, n=49, median age 42 years, 53% in CR, further ATG-S); rabbit ATG (ATG-Fresenius, n=38, median age 42 years, 58% in CR, further ATG-F) or no ATG (n=68, median age 36 years, 55% in CR). The groups were comparable regarding disease status at transplant, age, CMV status and cytogenetics. Grade III-IV acute GvHD was found in 15% in the ATG and 27% in the no ATG group (P=0.44). The most important independent risk factors for chronic GvHD (cGvHD) were the use of ATG, disease status at transplant and conditioning. cGvHD developed significantly more frequently in no ATG group. With the median follow-up of 34 months, the 5-year survival is 42% for those transplanted in CR. To conclude, these data demonstrate that the transplants performed in CR, with ATG, are associated with a good outcome, low incidence of cGvHD and no increase of relapse.

Dose-escalated treosulphan in combination with cyclophosphamide as a new preparative regimen for allogeneic haematopoietic stem cell transplantation in patients with an increased risk for regimen-related complications.

Treosulphan has recently demonstrated antileukaemic activity and potent haematopoietic stem cell toxicity. Dose-escalated treosulphan (3 x 12 or 3 x 14 g/m2) combined with cyclophosphamide (Cy) was chosen for a new preparative regimen before allogeneic haematopoietic stem cell transplantation in 18 patients (median age 44, range 19-64 years) with haematological malignancies, considered ineligible for other myeloablative preparative regimens. Pharmacokinetic studies demonstrated rapid treosulphan plasma clearance and a dose-dependent increase of its maximum plasma concentrations and area under the concentration-time curves. Rapid and sustained white blood cell and platelet recovery and full donor chimerism was attained in all evaluable patients. Nonhaematological regimen-related CTC grades 3-4 adverse events were transient and predominantly consisted of cardiac (28%), gastrointestinal (39%), and hepatic (39%) toxicities. The 1-year nonrelapse mortality was 22%. Principal causes of transplant-related lethal events were infections in three of four affected patients. Only one patient died from regimen-related cardiac toxicity. The 1-year relapse estimate is 22%, overall and progression-free survival estimates are 67 and 56%, respectively. In conclusion, this new treosulphan and Cy combination is an effective, comparatively well-tolerated myeloablative preparative regimen even in patients with an increased risk for regimen-related toxic complications.

Sequential application of chemotherapy and monoclonal CD 20 antibody: successful treatment of advanced composite-lymphoma.

We describe successful treatment of a 38-year-old patient with composite lymphoma stage IV(A), who presented with multifocal enlarged lymph nodes. The lymph node histology showed classic morphologic features of Hodgkin's disease, mixed cellularity subtype and follicular B-cell lymphoma. Immunophenotypic analysis showed immunoreactivity for CD20, CD10 and Ki-67 in the malignant small cell population. The areas of Hodgkin's disease demonstrated positive immunoreactivity for CD30 and CD20 in the Hodgkin's cells. Both cell populations were bcl2-oncoprotein positive. Eight courses of dose-escalated BEACOPP were administered. Restaging after chemotherapy showed radiological partial remission, but biopsy confirmed persisting follicular B-cell lymphoma without bone marrow infiltration and no evidence of Hodgkin's disease. He was treated with monoclonal CD 20-antibody (Rituximab) 10 mg/kg weekly for eight consecutive weeks due to marked positivity of CD 20-antigen in follicular lymphoma cells. This treatment was well tolerated and final staging showed complete remission of the composite lymphoma. This patient continues to be in remission 28 months after the end of the treatment. In conclusion, in the very rare case of composite lymphoma a combination of chemotherapy and subsequent immunotherapy might be considered as a promising therapeutic option.

Method for growing primitive erythroid progenitors (BFU-E) from rat bone marrow.

A method for growing erythroid bursts from rat bone marrow cells is presented. The methylcellulose culture technique with rat spleen-conditioned medium was used. Successful growth of rat BFU-E was obtained with 20% fetal bovine serum when anemic rat plasma was used as the source of erythropoietin. Plating efficiency was 60 BFU-E per 2 x 10(5) nucleated cells seeded. The proliferative activity determined by cytosine arabinoside (Ara-C) suicide was about 22%. The effect of chronic hypertransfusion on erythroid colony formation is presented.

Granulopoiesis in anemic Belgrade laboratory (b/b) rats.

The aim of this study was to clarify the nature of the abnormalities of granulopoiesis in anemic b/b rats. The size of different granulocytic cell compartments (granulocytic and macrophage precursor cells, proliferative and nonproliferative morphologically recognizable granulocytic cells) in the bone marrow, spleen, and peripheral blood was determined, and activity of granulocytic stimulators (colony-stimulating activities derived from lung-conditioned medium of endotoxin-treated rats and from spleen cells stimulated in vitro with pokeweed mitogen) was investigated. Depressed bone marrow granulopoiesis and expanded granulopoiesis in the spleen, together with the sustained production of granulocytic stimulators, was found in anemic b/b rats. It is suggested that the changes within the bone marrow microenvironment are the essential cause of disturbances of granulopoiesis in anemic b/b rats. The increased proliferation of granulocytic cells in iron-treated b/b rats indicates a role of iron in the cellular proliferation.

Erythroid progenitors in anemic Belgrade laboratory (b/b) rats.

The anemia of Belgrade b/b rats has been shown to be due to intracellular iron deficiency. The aim of this study of erythropoiesis at the progenitor cell level in these rats was to determine if a defect is present in the early phase of red cell production. Both erythroid colony-forming unit (CFU-E)- and erythroid burst-forming unit (BFU-E)-derived colonies were found to be few in untreated b/b rats and made up of a small number of poorly hemoglobinized erythroblasts of different size and irregular cell shape. Following treatment with iron, the anemia of the rats improved, and the number of CFU-E-derived colonies and the number of cells per colony increased, but the peculiar erythroblast morphology persisted. The high serum level of biologically active erythropoietin (Ep) in b/b rats rules out inadequate Ep production as a cause of their anemia. The results presented indicate, in addition to the earlier described defective transmembrane iron transport, a defect in erythroid progenitor cells. The effect of iron treatment in these rats detected in vitro on erythroid progenitors confirms the importance of iron for cellular proliferation.

Megakaryocytopoiesis in experimentally induced chronic normobaric hypoxia.

It was recently proposed that prolonged hypoxia produces hypomegakaryocytic thrombocytopenia by reducing the pool of committed megakaryocyte progenitor cells at the expense of a greatly expanded erythroid progenitor pool. In order to test this hypothesis we have studied the relationship between megakaryocytopoiesis, erythropoiesis, and granulopoiesis at the level of progenitor cells (megakaryocyte colony-forming unit, CFU-Mk; erythroid CFU, CFU-E; erythroid burst-forming units; BFU-E; and granulocyte-macrophage CFU, CFU-GM) in the marrow of rats exposed for 4 weeks to normobaric hypoxia. We have found that hypomegakaryocytic thrombocytopenia was accompanied by decreased CFU-Mk, increased CFU-E, and a normal number of BFU-E and CFU-GM. These results support the hypothesis that prolonged hypoxia reduces the precursor cell commitment to differentiate into the megakaryocyte series by enhancing demand for differentiation into the erythroid cell line. However, the underlying mechanism needs further investigation.

Erythrocytosis in spontaneously hypertensive rats.

Spontaneously hypertensive rats (SH) with an increased number of red blood cells (RBC), microcytosis, and normal hemoglobin (Hb) concentration were used to study the effect of different manipulations of the erythron on erythropoietin production and on erythroid progenitor proliferation by bone marrow cells in order to gain insight regarding the regulation of erythropoiesis. The serum erythropoietin (Ep) level was increased in untreated SH rats. After stimulation by either bleeding, hemolysis, or acute hypoxia, both the erythropoietin level and erythroid colony-forming unit (CFU-E) proliferation by bone marrow cells increased in SH rats to levels that were similar to those of normotensive Wistar (W) rats. Exposure to chronic hypoxia induced an increase in Hb concentration in SH rats concomitantly with the increase in RBC. The results obtained in SH rats raise the possibility of a defect in nonEp stimulators of erythropoiesis that may alter Hb synthesis.

Hematopoietic growth factors in anemia of Belgrade laboratory (b/b) rats.

In this study, the extent to which growth factor production and microenvironment might be responsible for defective erythropoiesis and granulopoiesis in anemic b/b rats is investigated. Radioimmunoassay-determined serum erythropoietin (Epo) levels are high in b/b rats and closely related to degree of anemia. The low number of erythroid progenitors in b/b rats despite a high Epo level suggested that the defective erythropoiesis could be due to a low level of burst-promoting activity (BPA). A pokeweed mitogen-stimulated medium (PWM-SCM) was prepared with b/b rat spleen cells and used in normal and anemic rat bone marrow and spleen cultures to determine BPA and other growth factor levels. No erythroid burst-forming unit-derived colonies were found but granulocyte-macrophage colony-forming units were counted in significant number, suggesting that the production of growth factors that supports the growth of granulopoietic progenitors is not significantly disturbed. Because BPA is produced mainly by T-lymphocytes, the low BPA level in b/b rat PWM-SCM raised the question of the functional capacity of T-lymphocytes. Investigations showed a decrease in the proliferative activity of b/b rat spleen mitogen-activated T-lymphocytes to about 20% of controls as well as a decrease in interleukin-2 activity in b/b rat spleen cell supernatants. These results point to defective T-lymphocytes. A study of bone marrow fibroblastoid cell colonies (CFU-F) revealed significantly lower CFU-F counts in the b/b rats. This finding is indicative of a disturbed microenvironment, which could also to some extent be responsible for decreased growth factor production and depressed hematopoiesis in the b/b rat.

New therapeutic modalities in the treatment of graft-versus-host disease.

Acute and chronic GvHD are still a major concern in allogeneic hematopoietic stem cell transplantation, still contributing substantially to morbidity and mortality in this therapeutic procedure. Over the past decade, many advances have been made with regard to the prevention and treatment of GvHD using various drugs such as cyclosporine A, FK506, mycophenolate mofetil and/or monoclonal IL-2 receptor antagonists. Despite these measurements with regard to the prevention of acute GvHD, it is very difficult to treat these clinical conditions successfully. However, if patients do not experience any GvHD often the desired effect of graft versus leukemia (GvL) remains absent increasing the probability of a relapse, in particular, in patients transplanted, which are considered at higher risk for relapse. At the present time, new strategies in the prevention of acute GvHD are in progress in particular the use of genetic manipulated donor T cells expressing suicide genes. Further clinical and laboratory studies are required in order to improve the prevention and, in particular, the therapy of established GvHD.

AdGVVEGF121.10 (GenVec).

GenVec, in collaboration with Pfizer (formerly Parke-Davis), is developing AdGVVEGF121.10 (BioBypass), a gene therapy involving the 121-residue isoform of vascular endothelial growth factor (VEGF), licensed from Scios, for the potential treatment of coronary artery disease (CAD) and peripheral vascular disease (PVD) [262000]. By March 2000, phase II trials in CAD had commenced [359531], [359532], [359538]. By August 2000, phase II trials were also underway for PVD [386293]. The initial phase II trial will include approximately 70 patients with severe CAD who are not candidates for bypass surgery and will assess exercise capacity and patient well-being, before and after treatment, as well as safety and drug tolerance [364137]. Scios licensed the gene transfer applications of VEGF121 to GenVec in June 1996 [263381]. In September 1997, GenVec entered into an agreement with Parke-Davis, a subsidiary of Warner-Lambert (now Pfizer), to develop the therapy [262000]. In May 1999, Warner-Lambert signed an agreement with Bioscience for a device for the administration of AdGVVEGF121.10 1325443]. In May 2000, Merrill Lynch predicted a US filing in the first half of 2003 [375962]. In January 2001, AG Edwards predicted the product would generate $70 million in revenues to Pfizer and $12 million in royalties to GenVec in 2005. In February 1999, GenVec was awarded US-05846782, covering vectors for targeting the transfer of therapeutic genes to specific tissues in the human body [316038].

A comparative study of peripheral blood stem cell vs bone marrow transplantation from unrelated donors (MUD): a single center study.

Peripheral blood stem cell transplants (PBSCT) from unrelated donors (n = 37) were compared with bone marrow transplants (BM, bone marrow group, n = 37) in a matched pair analysis. Ten patients (2, class 1) in the alloPBSCT group and seven patients (2, class 1) in the BM group had one HLA locus mismatch donor, respectively. The following factors were matched: HLA-compatibility, diagnosis, disease stage, age and gender. The median age in the PBSC group was 37 years (19-56, excluding one 6-year-old child) and in the BM group 37 years (18-53). The BM group consisted of 12 females and 25 males, 17 females and 20 males were in the PBSC group. Twelve patients in the BM and 11 patients in the PBSC group were diagnosed with AMI,; 7/7, ALL; 15/15, CML; 2/3, MDS; 1/1, NHL. Thirty-four (14/20) of the 74 patients (45%) were considered as high risk patients. The conditioning regimen was BU/CY for standard risk patients with myeloid diseases (31 patients) and TBI/CY for ALL and NHL patients (36 patients); six patients received intensified conditioning with VP16 (2 patients), thiotepa (2 patients) or melphalan (1 patient). The GVHD prophylaxis regimen was used according to the Seattle protocol. DFS was 51% (19 patients) with a median of 352 days and 59% (21 patients) with a median of 760 days, in PBSC and BM transplants, respectively. The median time to leukocyte engraftment in PBSC patients was 14 days (range 6-26 days) and in the BM group 19 days (range 9-29 days; P < 0.02). The time of platelet engraftment did not differ significantly between the groups. The incidence of grade II-IV acute GVHD was 40% (four patients died, 13%) in the PBSC group and 20)% (three patients died, 8%) in the BM group, respectively (P < 0.05, log-rank). No signs of aGVHD were found in 19% of the patients in the PBSC and 27% in the BM group. Our results indicate that allogeneic PBSCT does lead to a significantly faster leukocyte engraftment. The significant increase with regard to the incidence and shorter time of onset of severe aGVHD in PBSC patients, compared to marrow transplant patients, need to be confirmed in a randomised trial.

Lenograstim-mobilized peripheral blood progenitor cells in volunteer donors: an open label randomized split dose escalating study.

Mobilization of peripheral blood cell progenitor cells was investigated in 36 healthy sibling donors using three different split doses of glycosylated rhG-CSF (lenograstim). The donors were randomized into three groups: group 1 was given lenograstim at 8, group 2 at 11 and group 3 at 15 micrograms/kg/day in two split doses, subcutaneously for 4 and 5 days, respectively. Leukapheresis was performed on day 4 or 5 depending on the WBC and CD34+ cell count. We were able to demonstrate that there was a significant correlation between circulating CD34+ cells on the day of harvest and CD34+ cells in the apheresis products in all three groups. The number of CD34+ cells pre-apheresis was inversely correlated with age in group 1 and group 2. However, in group 3, the number of CD34+ cells pre-apheresis did not correlate with age. There was also a difference between the number of progenitor cells mobilized in the three dose groups regarding the time of harvest. Apheresis was performed in groups 1 and 2 on day 5 of mobilization in order to obtain a sufficient number of stem cells for allogeneic transplantation. In contrast, with the split dose of 15 micrograms/kg/day, harvest could be routinely performed on day 4 of stimulation. We conclude that lenograstim given twice a day at doses of 8, 11 and 15 micrograms/kg/day provided different CD34+ cell yields in normal donors, in particular, with regard to the time of harvest. The number of CD34+ cells pre-apheresis was not correlated with age in the group of donors mobilized with a split dose of 15 micrograms/kg/day, indicating that this dosage might also be suitable for older donors.

Reduced intensity preparative regimens for allogeneic hematopoietic stem cell transplantation: a single center experience.

According to recent reports, fast engraftment with minimal transplant-related toxicity and mortality (TRT, TRM) can be achieved by using reduced-intensity preparative regimens in allogeneic hematopoietic stem cell transplantation (HSCT). We report our experience with related (39%) and unrelated (61%) HSCT in 44 high risk patients (AML, ALL, CML, CLL) receiving either busulfan/fludarabine or busulfane/fludarabine/ATG or TBI/fludarabine as reduced-intensity preparative regimens. Organ toxicity was minimal with mild mucositis and no major bleeding. Acute GVHD was recorded in 64% of the patients. Twenty-three patients achieved complete remission after transplantation, and complete chimerism was obtained in all patients with stable engraftment (35 patients). Twenty-nine patients died: 15 due to relapse/progression, 14 due to TRM. Survival with median follow-up of 18.5 months was significantly better in patients with matched related transplants compared to patients with other transplants. However, there was no difference between related and unrelated transplants with regard to engraftment, TRM and GVHD. In conclusion, our results in high-risk patients transplanted in CR or with smoldering leukemia from a related donor are encouraging, although a longer follow-up and a larger group of patients is needed in order to evaluate the role of different reduced-intensity preparative regimens in unrelated and related HSCT.

Total body irradiation and cyclophosphamide is a conditioning regimen for unrelated bone marrow transplantation in a patient with chronic myelogenous leukemia and renal failure on hemodialysis.

Five years after the diagnosis of Ph chromosome-positive chronic myeloid leukemia (CML) a 31-year-old patient developed malignant nephrosclerosis with renal failure. He then underwent an allogeneic unrelated BMT in first chronic phase CML. The preparative regimen consisted of fractionated total body irradiation (TBI) and cyclophosphamide (CY). We studied the pharmacokinetics of cyclophosphamide on hemodialysis and compared clinical parameters including time to engraftment and toxicity with parameters of a patient with normal renal function who also received an unrelated marrow as treatment for CML in first chronic phase. Our results suggest that TBI/CY is a suitable conditioning regimen for allogeneic transplantation in patients with hematological malignancy and renal failure on hemodialysis.

Successful treatment of thrombocytopenia and hemolytic anemia with IvIG in a patient with lupus-like syndrome after mismatched related PBSCT.

Hematopoietic stem cell transplantation (HSCT) is a treatment option for autoimmune diseases but can also cause clinical features similar to those of autoimmune diseases. In some of these cases the autoimmune-like condition is associated with autoimmune cytopenia, a complication that can be unresponsive to established treatment strategies and which may be fatal. The majority of cases reported on immune hemolytic anemia have been of alloimmune origin due to ABO red blood cell antigen incompatibilities between donor and recipient. We now report a patient with a lupus-like syndrome, presenting with severe thrombocytopenia and hemolytic anemia 9 months after HLA-mismatch, ABO compatible-related PBSCT who experienced no response to high-dose steroids, but who had a sustained response to repeated IvIG therapy.

New strategies in the treatment of graft-versus-host disease.

GVHD continues to be a major complication after allogeneic hematopoietic stem cell transplantation even when the recipient is given immunosuppression for the prophylaxis of this severe disease. There have been many advances in the prevention and treatment of GVHD, using compounds such as cyclosporine, FK506, mycophenolate mofetil or monoclonal IL-2 receptor antagonist. New strategies seem to include sequential therapy involving the blocking of both endogenous cytokines and alloreactive donor cells. However, further clinical and laboratory studies are needed in order to improve the therapy of established GVHD.

New strategies in GVHD prophylaxis.

Despite immunosuppressive therapy using cyclosporine (CsA) and prednisolone and methotrexate (MTX), the incidence for aGVHD grade II to IV after transplantation from HLA matched unrelated donors (MUD) is 78%, the incidence for grade III and IV 36%. Since GVHD contributes to morbidity and mortality after MUD-BMT, a more effective prophylactic regimen is needed in order to prevent these transplant-associated complications. Recently, we described that mycophenolate mofetil (MMF, CellCept), an immunosuppressive agent successfully used for the prevention of acute rejection in renal allograft recipients, can safely and effectively be used for the treatment of aGVHD in hematopoietic stem cell transplantation. Information on the i.v. formulation of mycophenolic acid (MPA) is not yet available. Here we report on the i.v. formulation of MMF in hematopoietic stem cell recipients. MMF is effective in the prophylaxis of acute GVHD after stem cell transplantation; the optimal dosage needs further investigation. At the present time the relevance of measurement of plasma MPA concentrations on MMF dosage is not yet understood and further evaluation is required.

Peracute onset of severe tumor lysis syndrome immediately after 4 Gy fractionated TBI as part of reduced intensity preparative regimen in a patient with T-ALL with high tumor burden.

We report a 30-year-old patient with therapy-refractory T-ALL undergoing unrelated allogeneic PBSCT. He developed severe tumor lysis syndrome (TLS) with extreme biochemical changes, cardiac and neurological symptoms and dialysis-dependent acute renal failure after TBI (4 Gy) on the first day of reduced intensity conditioning (RIC) for unrelated allogeneic PBSCT. The patient's clinical condition was stabilized after beginning daily hemodialysis and treatment for disturbed electrolytes, metabolic acidosis and plasma coagulation, as well as reduction of uric acid by rasburicase. The conditioning therapy and the allogenic PBSCT were scheduled according to the preparative regimen. According to our knowledge, severe TLS induced by 4 Gy TBI has not been reported so far. Regimen-related toxicity using RIC regimen was mild, allowing 30-50% of the patients to have an entirely outpatient transplantation. However, we would like to point out that severe TLS could also complicate PBSCT using RIC regimens in patients with relatively radiation-sensitive malignancies and high tumor burden.