[Show abstract][Hide abstract] ABSTRACT: http://www.karger.com/Article/Abstract/227231
Polyclonal intravenous IgG (IVIG) was administered as an infusion 6 times every 3 weeks (weekO, 3, 6, 9, 12, 15) in doses of 0.1, 0.4 and 0.8 g/kg BW to determine the dose causing an increase in 12 pneumococcal antibody types above the protective level of 200 ng/ml of antibody N. The dose of 0.4 g/kg BW was found to be optimal in patients with chronic lymphocytic leukaemia (CLL). From the first infusion onwards at least 80% of CLL patients had increases in all 12 antibodies. Five weeks after the last infusion the antibody levels were still elevated in 80% of patients with CLL. The dose of 0.8 g/kg raised all 12 antibodies in 53–73% of CLLpatients when assessments were made after each infusion. In multiple myeloma (MM) patients, 73–82% and 73–91 % of patients had increased antibody levels, respectively, before and after the 4th–6th infusions at the 0.8 g/kg dose level. However, in only 45–50% of patients did the antibodies remain increased 2 weeks after the treatment at this dose. The dose of 0.4 g/kg caused antibody increases in only 30–50% of patients when measured before the 4th–6th infusion. Serum IgG increased significantly only in the CLL patients, whereas in the MM patients it was high from the beginning owing to the disease. Therefore, the pneumococcal antibody levels were a better marker for the purpose of dose finding. The dosage recommendation in CLL is 0.4 g/kg every 3 weeks until week 12, when steady state is reached. The maintenance dose is 0.4 g/kg every 5 weeks. In MM patients, who have a faster elimination rate of antibodies, the recommended loading dose is 0.8 g/kg, followed by 0.4 g/kg every week as a continuous treatment. Treatment with IVIG in CLL and MM was generally well tolerated. Only 25% of patients experienced minor side-effects, the most frequent being febrile reactions, shivering and headache.
[Show abstract][Hide abstract] ABSTRACT: To analyze the outcome, including nonrelapse mortality (NRM), relapse rate (RR), progression-free survival (PFS), and overall survival (OS), of patients with diffuse large B-cell non-Hodgkin's lymphoma (DLBCL) relapsed after an autologous stem-cell transplantation (ASCT) and treated with an allogeneic stem-cell transplantation (allo-SCT).
The European Group for Blood and Marrow Transplantation database was scanned for a first allo-SCT in relapsed DLBCL after a previous ASCT between 1997 and 2006. Other inclusion criteria were age at allo-SCT ≥ 18 years and availability of an HLA-identical sibling or a matched unrelated donor. A total of 101 patients (57 males; median age, 46 years) were included. Median follow-up for survivors was 36 months.
Myeloablative conditioning regimen was used in 37 patients and reduced intensity conditioning (RIC) was used in 64 patients. Three-year NRM was 28.2% (95% CI, 20% to 39%), RR was 30.1% (95% CI, 22% to 41%), PFS was 41.7% (95% CI, 32% to 52%), and OS was 53.8% (95% CI, 44% to 64%). NRM was significantly increased in patients ≥ 45 years (P = .01) and in those with an early relapse (< 12 months) after ASCT (P = .01). RR was significantly higher in refractory patients (P = .03). A time interval to relapse after ASCT of < 12 months was associated with lower PFS (P = .03). The use of RIC regimens was followed by a trend to a lower NRM (P = .1) and a trend to a higher RR (P = .1), with no differences in PFS and OS. No differences were seen between HLA-identical siblings and matched unrelated donors.
Allo-SCT in relapsed DLBCL after ASCT is a promising therapeutic modality. Patients with a long remission after ASCT and with sensitive disease at allo-SCT are the best candidates for this approach.
Journal of Clinical Oncology 02/2011; 29(10):1342-8. · 17.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We analyzed 368 chronic lymphocytic leukemia patients who underwent allogeneic hematopoietic stem cell transplantation reported to the EBMT registry between 1995 and 2007. There were 198 human leukocyte antigen (HLA)-identical siblings; among unrelated transplants, 31 were well matched in high resolution ('well matched' unrelated donor, WMUD), and 139 were mismatched (MM), including 30 matched in low resolution; 266 patients (72%) received reduced-intensity conditioning and 102 (28%) received standard. According to the EBMT risk score, 11% were in scores 1-3, 23% in score 4, 40% in score 5, 22% in score 6 and 4% in score 7. There was no difference in overall survival (OS) at 5 years between HLA-identical siblings (55% (48-64)) and WMUD (59% (41-84)), P=0.82. In contrast, OS was significantly worse for MM (37% (29-48) P=0.005) due to a significant excess of transplant-related mortality. Also OS worsened significantly when EBMT risk score increased. HLA matching had no significant impact on relapse (siblings: 24% (21-27); WMUD: 35% (26-44), P=0.11 and MM: 21% (18-24), P=0.81); alemtuzumab T-cell depletion and stem cell source (peripheral blood) were associated with an increased risk. Our findings support the use of WMUD as equivalent alternative to HLA-matched sibling donors for allogeneic HSCT in CLL, and justify the application of EBMT risk score in this disease.
Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K 10/2010; 24(10):1725-31. · 10.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study was performed to examine the characteristics of transplant activity for patients with myelodysplastic syndromes (MDS) older than 50 years within the European Group for Blood and Marrow Transplantation, and to evaluate the factors predicting outcome within this group of patients.
We performed a retrospective multicenter analysis of 1,333 MDS patients age 50 years or older who received transplantation within the EBMT since 1998. The median recipient age was 56 years, with 884 patients (66%) age 50 to 60 years and 449 (34%) patients older than 60 years. There were 811 HLA-matched sibling (61%) and 522 (39%) unrelated donor transplants. Five hundred patients (38%) received standard myeloablative conditioning (SMC), and 833 (62%) received reduced intensity conditioning (RIC).
The 4-year estimate for overall survival of the whole cohort was 31%. On multivariate analysis, use of RIC (hazard ratio [HR], 1.44; 95% CI, 1.13 to 1.84; P < .01) and advanced disease stage at transplantation (HR, 1.51; 95% CI, 1.18 to 1.93; P < .01) were associated with an increased relapse rate. In contrast, advanced disease stage at transplantation (HR, 1.43; 95% CI, 1.13 to 1.79; P = .01), use of an unrelated donor (P = .03), and RIC (HR, 0.79; 95% CI, 0.65 to 0.97; P = .03) were independent variables associated with nonrelapse mortality. Advanced disease stage at transplantation (HR, 1.55; 95% CI, 1.32 to 1.83; P < .01) was the major independent variable associated with an inferior 4-year overall survival.
Allogeneic hematopoietic stem-cell transplantation remains a potential curative therapeutic option for many older patients with MDS. In this analysis, disease stage at time of transplantation, but not recipient age or the intensity of the conditioning regimens, was the most important factor influencing outcomes.
Journal of Clinical Oncology 12/2009; 28(3):405-11. · 17.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: : Central nervous system infection due to Torulopsis glabrata is very rare. The paper describes the case of a 22-year-old patient who died from multiple brain abscesses due to Torulopsis glabrata 3 months after a bone marrow transplantation, in spite of prophylaxis with ketoconazole and treatment with itraconazole and amphotericin B.Zusammenfassung: Eine Infektion des Zentralnervensystems mit Torulopsis glabrata ist nur äußerst selten zu beobachten. Es wird berichtet Uber einen 22jährigen Patienten, der drei Monate nach einer Knochenmarktransplantation, trotz prophylaktischer Behandlung mit Ketoconazol und Gabe von Itraconazol und Amphoterizin B, an multiplen Hirnabszessen infolge Torulopsis glabrata-Infektion starb.
[Show abstract][Hide abstract] ABSTRACT: To investigate whether intracoronary transfer of bone marrow progenitor cells (BMPCs) early after reperfusion of an acute myocardial infarction improves regional myocardial function in a randomized double-blind, placebo-controlled strain rate imaging study.
Regional myocardial deformation was measured using velocity-derived strain rate imaging in 67 STEMI patients randomized 1:1 to intracoronary infusion of BMPC (n = 33) or placebo (n = 34). Myocardial segments were grouped into infarct (n = 232), border (n = 250), and remote (n = 526) based on MRI-delayed enhancement and the perfusion territory of the infarct-related vessel. Four months after revascularization and progenitor cell/placebo transfer, regional myocardial deformation (rate) improved significantly more in the infarct segments of BMPC patients (treatment effect on end-systolic strain: -3.7 +/- 1.0%, P = 0.0003; peak-systolic strain rate: -0.20 +/- 0.07 s(-1), P = 0.0035). These findings were confirmed by a significantly greater improvement of longitudinal mitral valve ring displacement in the infarct walls of BMPC patients (treatment effect: 0.93 mm, P = 0.034).
Intracoronary infusion of BMPC early after reperfusion of a STEMI improves recuperation of regional myocardial function at 4 months' follow-up. Quantitative assessment of regional systolic function might be more sensitive than global LV ejection fraction for the evaluation of BMPC therapy after STEMI.
European Heart Journal 01/2009; 30(6):662-70. · 14.72 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fludarabine is an antineoplastic agent used in the treatment of hematological malignancies, particularly chronic lymphocytic leukemia (CLL) and indolent B-cell lymphoma. Because of its immunosuppressive effects, fludarabine has been added to reduced intensity conditioning regimens. The oral formulation of fludarabine has become widely available. Pharmacokinetic studies have shown that an oral dose of 40 mg/m(2)/d would provide systemic drug exposure similar to the standard intravenous (IV) dose of 25 mg/m(2)/d. The oral dose can be taken once daily without any dietary restrictions. Dose adjustments are mandatory in patients with renal impairment to avoid increased toxicity. Several noncomparative trials in previously untreated and treated patients with CLL have shown that treatment with the oral formulation demonstrates similar efficacy compared to historical control groups treated with the IV formulation. The tolerability profile of oral fludarabine seems similar to that of the IV formulation. Myelosuppression and infectious complications are the most frequently reported adverse events. Gastrointestinal toxicity is more frequent with the oral formulation, but is usually of mild or moderate severity. Although oral fludarabine makes treatment more convenient, health care workers must be aware of the compliance behavior of each patient.
Drug Design, Development and Therapy 01/2009; 3:241-52. · 3.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Infection remains the principal cause of morbidity and mortality in febrile neutropenic episodes in cancer patients. During the 1960s and 1970s, infection was responsible for 80% of deaths in patients with hematological malignancy, but observations from clinical trials completed by the International Antimicrobial Therapy Cooperative Group of the European Organisation for Research and Treatment of Cancer (IATCG-EORTC) show that in recent years, mortality rates due to infection have fallen to approximately 3% in patients undergoing active treatment of the malignancy. For patients considered beyond active treatment, figures are much higher. This improvement is undoubtedly due to the introduction and use of empirical therapy in the early 1970s. The rationale for developing the concept of empirical therapy was based on the fact that blood culture results may not be available for several days, with disastrous consequences for treatment of a rapidly progressing infection. Therefore, antibiotics are given to febrile neutropenic cancer patients without definitive microbiological proof of infection.Many studies on empirical therapy have investigated combinations of agents, such as a β-lactam plus an aminoglycoside. Such antibiotic combinations offer broad-spectrum antibacterial coverage and have been shown to provide synergistic bactericidal effects against Gram-negative pathogens in vitro. However, in recent trials on the comparison between mono- and combination therapy the time to defervescence did not significantly differ, suggesting that a more synergistic bactericidal effect, as observed in vitro with combinations, did not have a measurable counterpart in vivo on fever duration. Combinations may also reduce the emergence of resistant isolates that are observed when certain β-lactam antibiotics are used alone. Aminoglycoside-containing regimens are, however, associated with ototoxicity and nephrotoxicity. In efforts to circumvent this, some investigators have used double β-lactam combinations but, recently, monotherapy with newer extended-spectrum agents such as the carbapenems, third- and fourth-generation cephalosporins and fluoroquinolones have become increasingly studied and used as standard empirical therapy.The criteria for evaluating the response to empirical antibiotic treatment in febrile neutropenia have evolved from a number of clinical trials. These studies have indicated that age, the duration of neutropenia, the nature of the underlying disease, the causative pathogen, the availability of new effective drugs, and the chosen end point all have a profound influence on response rates. Moreover, a clear understanding of the objectives and design of trials is of paramount importance in interpretation of the results and comparison of data from different trials. Recently, there has been a move towards more rational use of antibiotics with the identification of patient subgroups at lower risk of unfavourable outcome, who might be treated more appropriately with less aggressive, tailored, empirical therapy. This review examines the effectiveness of empirical therapy in studies from different centers during the last 20 years, and looks towards possibilities for modification of treatment strategies in the future, to combat emergence of new pathogens and the development of resistance in established pathogens.
[Show abstract][Hide abstract] ABSTRACT: Morphological, immunological and cytogenetic features were studied in 27 adults presenting with Ph chromosome-positive acute lymphoblastic leukaemia (ALL), in correlation with clinical outcome.Twenty patients (group 1) were diagnosed as having typical ALL according to the FAB criteria supported by immunological findings. Less than 1% blast cells with azurophilic granules were detected in all cases. Myeloid cytochemistry, i.e. peroxidase and Sudan black-B stain, was negative in all cases. A minor phenotype deviation consisting of the expression of the CD13 myeloid-associated marker was detected in two patients.In seven patients (group 2) a diagnosis of ALL with a minor myeloid component was made because of the presence of a majority of lymphoid blasts and of 5-15% blast cells with morphological cytochemical and immunological features of the myeloid lineage.Abnormal metaphases were found in 6/20 (30%) patients in group 1, compared with 7/7 (100%) patients in group 2.All patients were treated by antilymphoid regimens: however, complete remission was achieved in 17/20 (85%) patients in group 1 versus 1/7 (14.3%) patients in group 2. Median survival was 16 months, range <1-120+ in group 1 and 9 months, range <1-15 in group 2.It is concluded that morphological, immunological and cytogenetic studies allow for the recognition of two cytological subsets of Ph+ ALL. The presence of a minor myeloid component in otherwise typical Ph chromosome-positive ALL may be associated with a distinct cytogenetic pattern and poor responses to antilymphoid therapy.
British Journal of Haematology 10/2008; 87(3):515 - 522. · 4.94 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We studied the immune compartment in patients with myelodysplastic syndromes. We show increased surface expression of activation markers (HLA-DR(+), CD57(+), CD28(-), CD62L(-)) on T lymphocytes in blood and bone marrow (n=131). T cell activation was not restricted to any relevant clinical subgroup (FAB, IPSS, cytogenetics) and did not correlate with blood counts or need for treatment. In vitro clonogenic growth of marrow mononuclear cells (n=18) was not influenced by T cells expressing these markers. In addition, using X-chromosome inactivation analysis (n=12) we demonstrate clonal involvement of NK and B cells in half of these patients. We conclude that although activated T lymphocytes can be found in MDS, their role in disease pathogenesis remains unclear in the majority of patients.
Leukemia Research 08/2008; 32(7):1026-35. · 2.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Growth factors are frequently used to aid peripheral blood progenitor cell mobilization from bone marrow. This phase 2 study examined the efficacy and safety of pegfilgrastim for mobilizing peripheral blood progenitors cells for autologous transplantation.
Patients with non-Hodgkin's lymphoma received one cycle of mobilizing chemotherapy (ifosfamide, carboplatin and etoposide, ICE). Twenty-four hours later they were randomized, double-blind, to receive a single dose of pegfilgrastim 6 mg or 12 mg, or filgrastim 5 mug/kg/day (until the end of leukapheresis). Following leukapheresis (collection phase), patients rested or received one or two 'salvage' cycles of ICE. High-dose BEAM chemotherapy was then given before peripheral blood progenitor cell transplantation. The primary end-point was the patients' mean yield of CD34(+) cells/kg during the collection phase.
Ninety patients were randomized and received a study drug; 63% completed the collection phase. The patients' mean (95% CI) CD34(+) cell harvest per leukapheresis was 0.8 (0.5-1.4), 0.8 (0.5-1.6) and 1.2 (0.7-2.0)x10(6) cells/kg for the pegfilgrastim 6 mg, pegfilgrastim 12 mg and filgrastim groups, respectively. Twenty (69%), 17 (59%) and 23 (72%) patients in these three groups achieved the targeted minimum harvest (>/=2 x 10(6) cells/kg). The mean total harvests were 1.7, 1.4 and 2.2 x 10(6) cells/kg, respectively. Post-transplantation, the median days to absolute neutrophil count recovery (>/=0.5 x 10(9)/L) were 12, 11, and 11, respectively. Pegfilgrastim and filgrastim were generally well tolerated.
Pegfilgrastim (6 or 12 mg) was effective for mobilizing peripheral blood progenitors cells in patients with non-Hodgkin's lymphoma. These data may aid the design of studies to clarify optimal dosing and leukapheresis with pegfilgrastim.
[Show abstract][Hide abstract] ABSTRACT: Immune mechanisms have been shown to contribute to the process of myelodysplastic syndromes (MDS)-related bone marrow (BM) failure. The aim of this study was to evaluate the possible contribution of activated monocytes through CD40-CD40L(CD154) interactions with activated T helper cells. We demonstrated in 77 predominantly lower risk MDS patients that the CD40 receptor was expressed significantly higher on monocytes and that CD40L was expressed significantly higher on T helper cells in peripheral blood (PB) and BM. Increased levels of CD40 and CD40L were detected in the same patients. In addition, stimulation of the CD40 receptor on purified PB monocytes led to a significantly higher tumor necrosis factor alpha production in patients. Co-culture of BM mononuclear cells of 21 patients in the presence of a blocking CD40 monoclonal antibody (ch5D12) led to a significant increase in the number of colony-forming units. A correlation was seen between increased CD40 expression on monocytes with patients' age below 60 years and with the cytogenetic abnormality trisomy 8. These results demonstrate that CD40 expression on monocytes may identify a subgroup of MDS patients in whom immune-mediated hematopoietic failure is part of the disease process. As such, the CD40-CD40L-based activation of monocytes might be a target to counteract MDS-related BM failure.
Leukemia: official journal of the Leukemia Society of America, Leukemia Research Fund, U.K 01/2008; 21(12):2411-9. · 10.16 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: To compare the clinical outcome in terms of nonrelapse mortality (NRM), relapse rate (RR), overall survival (OS), and progression-free survival (PFS) in patients with relapsed Hodgkin's lymphoma (HL) treated with reduced-intensity conditioning (RIC) or myeloablative conditioning followed by allogeneic stem-cell transplantation (alloSCT).
A total of 168 patients with HL undergoing a first alloSCT (RIC, n = 89; myeloablative conditioning, n = 79) between January 1997 and December 2001 and registered in the European Group for Blood and Marrow Transplantation database were analyzed.
NRM was significantly decreased in the RIC group (hazard ratio [HR], 2.85; 95% CI, 1.62 to 5.02; P < .001). OS was better in the RIC group (HR, 2.05; 95% CI, 1.27 to 3.29; P = .04) and there was a trend for better PFS in the RIC group (HR, 1.53; 95% CI, 0.97 to 2.40; P = .07). RR was higher in the RIC group in univariate but not in multivariate analysis. The development of chronic graft-versus-host disease (GVHD) significantly decreased the incidence of relapse, which translated into a trend for a better PFS.
The lower incidence of NRM in the RIC group is encouraging, particularly because these patients experienced adverse pretransplantation characteristics more frequently. This analysis also indicates the existence of a graft-versus-HL effect correlated to the development of GVHD. Additional efforts to reduce the high RR seen in both groups of patients will be necessary to improve the modest PFS (31% v 27%) and OS (59% v 36%) for patients prepared with RIC or myeloablative conditioning.
Journal of Clinical Oncology 01/2008; 26(3):455-62. · 17.88 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dendritic cells (DC) are pivotal for T cell-mediated immunity. We investigated the early and terminal maturation of monocyte-derived DC (MoDC) in myelodysplastic syndromes (FAB subtypes refractory anemia (MDS-RA) or refractory anemia with ringed sideroblasts (MDS-RARS)). Immature MoDC were obtained by culture of monocytes with GM-CSF and IL-4 for 8 days. To obtain mature MoDC, TNF-alpha was added during the final three culture days. T cell proliferation and T cell cytokine secretion in mixed lymphocyte reactions (MLR) unveiled a strong reduction of allostimulatory capacity of mature but also of immature MoDC from MDS patients. Immature MoDC from MDS patients exhibited an almost normal immunophenotype, but secreted substantially less IL-12 and more IL-10 in response to LPS/IFN-gamma than normal controls. Terminal addition of TNF-alpha to GM-CSF/IL-4 treated monocytes failed to extinguish cytokine production by MDS MoDC and failed to induce the expected membrane upregulation of costimulatory and other ligands as in normal controls. While our data provide further support for previous studies that have indicated an impaired differentiation of immature towards mature MoDC, they also clearly demonstrate a qualitatively and quantitatively altered cytokine secretion at the level of immature MoDC, which may in part explain the reduced allostimulatory capacity of these cells. These alterations may contribute to immune modulation of the clinical phenotype of marrow failure in MDS, and may have to be considered when designing DC-based immunotherapeutic strategies for MDS.
Leukemia Research 11/2007; 31(10):1373-82. · 2.69 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Hematopoietic cell transplantation (HCT) is an effective treatment for myelodysplasia (MDS) and secondary acute myeloid leukemia (sAML). In this study, outcome of 593 patients with MDS/sAML after autologous and allogeneic HCT from a matched unrelated donor (MUD) were compared. A total of 167 (28%) patients received HCT from MUD without prior chemotherapy (MUD-U). The rest received HCT in first complete remission (CR1) (Autologous (Auto-CR1), n=290 (49%), HCT from MUD (MUD-CR1), n=136 (23%)). Survival at 3 years was best in MUD-CR1 (50%) compared to Auto-CR1 (41%) and MUD-U (40%) (P=0.01). Similarly, disease-free survival was 44% for MUD-CR1 compared to Auto-CR1 (28%) and MUD-U (34%) (P=0.03). Treatment-related mortality was 17% in Auto-CR1 compared to MUD-CR1 (38%) and MUD-U (49%) (P<0.001). Relapse for Auto-CR1 was 62% compared to 24 and 30% for MUD-CR1 and MUD-U, respectively (P<0.001). Outcome was best for patients with low tumor burden transplanted 6-12 months after diagnosis. Factors influencing outcome at 3 years were mainly significant in the first 6 months. Only, relapse after autologous HCT remained constant over time. Outcomes after allogeneic HCT in patients of 20-40 and >40 years were similar. Autologous and Allogeneic HCT from MUD offer the possibility of long-term survival to patients with MDS/sAML.
[Show abstract][Hide abstract] ABSTRACT: Multilineage dysplasia was advanced by the World Health Organization to increase prognostic accuracy in myelodysplastic syndromes (MDS) classification. We performed a structured cytomorphological examination of bone marrow (BM) in 221 low-grade MDS patients, this in conjunction with strict guidelines for cytopenias. A dysplasia scoring system was developed utilizing dysplastic changes, which were associated with worse outcome on univariate and multivariate analysis corrected for the International Prognostic Scoring System (IPSS). Dysplasia >or=10% in one BM lineage and one cytopenia constituted the low-risk category UCUD or Unilineage Cytopenia and Unilineage Dysplasia. The high-risk category comprised patients with cytopenia in >or=2 lineages and dysplasia in >or=2 BM lineages, namely MCMD or Multilineage Cytopenia and Multilineage Dysplasia. Intermediate-risk patients had one cytopenia and multilineage dysplasia, or cytopenia in >or=2 lineages and unilineage BM dysplasia, designated UCMD/MCUD or Unilineage Cytopenia and Multilineage Dysplasia/Multilineage Cytopenia and Unilineage Dysplasia. This system utilizing cytopenia-dysplasia scoring at diagnosis enabled comprehensive categorization of low-grade MDS cases that predicted for overall as well as leukemia-free survival. Cytopenia-dysplasia categorization added additional prognostic values to the lower risk IPSS categories. This suggests that a standardized dysplasia scoring system, used in conjunction with cytopenia, could improve diagnostic and prognostic sub-categorization of MDS patients.
[Show abstract][Hide abstract] ABSTRACT: The FIP1L1-PDGFRA oncogene is a common cause of chronic eosinophilic leukemia (CEL), and encodes an activated tyrosine kinase that is inhibited by imatinib. FIP1L1-PDGFRA-positive patients with CEL respond to low-dose imatinib therapy, but resistance due to acquired T674I mutation has been observed. We report here the identification of sorafenib as a potent inhibitor of the FIP1 like 1-platelet-derived growth factor receptor alpha (FIP1L1-PDGFRalpha) (T674I) mutant. Sorafenib inhibited the proliferation of FIP1L1-PDGFRalpha and FIP1L1-PDGFRalpha(T674I)-transformed Ba/F3 cells and induced apoptosis of the EOL-1 cell line at a low nanomolar concentration. Western blot analysis confirmed that these effects were due to a direct effect on FIP1L1-PDGFRalpha and FIP1L1-PDGFRalpha(T674I). Sorafenib was recently approved for the treatment of renal cell carcinoma. Our data suggest that low doses of sorafenib could be efficient for the treatment of FIP1L1-PDGFRA-positive CEL and could be used to overcome resistance to imatinib associated with the T674I mutation.