Real-world effectiveness of caplacizumab vs the standard of care in immune thrombotic thrombocytopenic purpura.

Immune thrombotic thrombocytopenic purpura (iTTP) is a thrombotic microangiopathy caused by anti-ADAMTS13 antibodies. Caplacizumab is approved for adults with an acute episode of iTTP in conjunction with plasma exchange (PEX) and immunosuppression. The objective of this study was to analyze and compare the safety and efficacy of caplacizumab vs the standard of care and assess the effect of the concomitant use of rituximab. A retrospective study from the Spanish TTP Registry of patients treated with caplacizumab vs those who did not receive it was conducted. A total of 155 patients with iTTP (77 caplacizumab, 78 no caplacizumab) were included. Patients initially treated with caplacizumab had fewer exacerbations (4.5% vs 20.5%; P < .05) and less refractoriness (4.5% vs 14.1%; P < .05) than those who were not treated. Time to clinical response was shorter when caplacizumab was used as initial treatment vs caplacizumab used after refractoriness or exacerbation. The multivariate analysis showed that its use in the first 3 days after PEX was associated with a lower number of PEX (odds ratio, 7.5; CI, 2.3-12.7; P < .05) and days of hospitalization (odds ratio, 11.2; CI, 5.6-16.9; P < .001) compared with standard therapy. There was no difference in time to clinical remission in patients treated with caplacizumab compared with the use of rituximab. No severe adverse event was described in the caplacizumab group. In summary, caplacizumab reduced exacerbations and refractoriness compared with standard of care regimens. When administered within the first 3 days after PEX, it also provided a faster clinical response, reducing hospitalization time and the need for PEX.

Azacitidine vs. Decitabine in Unfit Newly Diagnosed Acute Myeloid Leukemia Patients: Results from the PETHEMA Registry.

The hypomethylating agents, decitabine (DEC) and azacitidine (AZA), allowed more elderly acute myeloid leukemia (AML) patients to be treated. However, there are little direct comparative data on AZA and DEC. This multicenter retrospective study compared the outcomes of AZA and DEC in terms of response and overall survival (OS). Potential predictors associated with response and OS were also evaluated. A total of 626 AML patients were included (487 treated with AZA and 139 with DEC). Response rates were similar in both groups: CR was 18% with AZA vs. 23% with DEC (p = 0.20), CR/CRi was 20.5% vs. 25% (p = 0.27) and ORR was 32% vs. 39.5% (p = 0.12), respectively. Patients with leukocytes < 10 × 109/L, bone marrow blasts < 50% and ECOG ≥ 2 had higher ORR with DEC than with AZA. OS was similar in both groups: 10.4 months (95% CI: 9.2−11.7) vs. 8.8 months (95% CI: 6.7−11.0, p = 0.455), for AZA and DEC, respectively. Age (≥80 years), leukocytes (≥ 10 × 109/L), platelet count (<20 × 109/L) and eGFR (≥45 mL/min/1.73 m2) were associated with higher OS with AZA compared to DEC. In conclusion, we found no differences in response and OS rates in AML patients treated with AZA or DEC.

The Mutational Landscape of Acute Myeloid Leukaemia Predicts Responses and Outcomes in Elderly Patients from the PETHEMA-FLUGAZA Phase 3 Clinical Trial.

We sought to predict treatment responses and outcomes in older patients with newly diagnosed acute myeloid leukemia (AML) from our FLUGAZA phase III clinical trial (PETHEMA group) based on mutational status, comparing azacytidine (AZA) with fludarabine plus low-dose cytarabine (FLUGA). Mutational profiling using a custom 43-gene next-generation sequencing panel revealed differences in profiles between older and younger patients, and several prognostic markers that were useful in young patients were ineffective in older patients. We examined the associations between variables and overall responses at the end of the third cycle. Patients with mutated DNMT3A or EZH2 were shown to benefit from azacytidine in the treatment-adjusted subgroup analysis. An analysis of the associations with tumor burden using variant allele frequency (VAF) quantification showed that a higher overall response was associated with an increase in TET2 VAF (odds ratio (OR), 1.014; p = 0.030) and lower TP53 VAF (OR, 0.981; p = 0.003). In the treatment-adjusted multivariate survival analyses, only the NRAS (hazard ratio (HR), 1.9, p = 0.005) and TP53 (HR, 2.6, p = 9.8 × 10-7) variants were associated with shorter overall survival (OS), whereas only mutated BCOR (HR, 3.6, p = 0.0003) was associated with a shorter relapse-free survival (RFS). Subgroup analyses of OS according to biological and genomic characteristics showed that patients with low-intermediate cytogenetic risk (HR, 1.51, p = 0.045) and mutated NRAS (HR, 3.66, p = 0.047) benefited from azacytidine therapy. In the subgroup analyses, patients with mutated TP53 (HR, 4.71, p = 0.009) showed a better RFS in the azacytidine arm. In conclusion, differential mutational profiling might anticipate the outcomes of first-line treatment choices (AZA or FLUGA) in older patients with AML. The study is registered at ClinicalTrials.gov as NCT02319135.

Defibrotide in hematopoietic stem cell transplantation: A multicenter survey study of the Spanish Hematopoietic Stem Cell Transplantation Group (GETH).

BACKGROUND: Defibrotide is approved in European Union for the treatment of severe sinusoidal obstruction syndrome (SOS) after HSCT. However, it has also been used for SOS prophylaxis, moderate SOS and in other complications such as transplant-associated thrombotic microangiopathy (TAM). The objective of this study was to evaluate current uses, effectiveness and safety of defibrotide in patients with HSCT. METHODS: This multicenter, retrospective study included patients treated with defibrotide for any indication at 28 HSCT centers of the Grupo Español de Trasplante Hematopoyetico (GETH) including the pediatric subgroup Grupo Español de Trasplante de Medula en Niños (GETMON). RESULTS: Three hundred and eighty eight patients treated with defibrotide between January 2011 and December 2018 were included. 253 patients were children, and 135 patients were adults. In total, 332 transplants were allogeneic, and the remainder were autologous. Main indications for defibrotide use were severe/very severe SOS in 173 patients, SOS prophylaxis in 135 patients, moderate SOS in 41 patients, TAM in six patients and suspected SOS in 33 patients. Overall survival (OS) at day +100 in the SOS prophylaxis group was 89% (95% CI, 87%-91%). In the group of patients with moderate and severe/very severe SOS, the OS at day +100 was 80% (95% CI, 74%-86%) and 62% (95% CI, 59%-65%), respectively (P = .0015). With a longer follow-up, median of 2 years (4 months-7 years), OS was 63% (95% CI, 59%-67%) in the SOS prophylaxis patients. OS for patients with moderate and severe/very severe SOS groups was 53% (95% CI, 47%-61%) and 26% (95% CI, 22%-30%), respectively (P = .006). 191 patients died, and SOS was the main cause of death in 23 patients (12%). CONCLUSIONS: Defibrotide has an acceptable safety profile with an improved response in severe/very severe SOS compared with historical controls, mainly in pediatric patients. Use of defibrotide for prophylaxis may improve prognosis of patients at high risk of complications due to endothelial damage such as those who receive a second transplant. SOS has an important impact on the HSCT long-term survival, as can be concluded from our study.

Pomalidomide, Cyclophosphamide, and Dexamethasone for the Treatment of Relapsed/Refractory Multiple Myeloma: Real-World Analysis of the Pethema-GEM Experience.

INTRODUCTION: Treatment of relapsed/refractory multiple myeloma (RRMM) is highly challenging, especially for patients with disease refractory to initial therapy, and in particular for disease developing refractoriness to lenalidomide. Indeed, with currently approved treatments, median progression-free survival (PFS) in the lenalidomide-refractory setting is less than 10 months, reflecting the difficulty in treating this patient population. Pomalidomide is a second-generation immunomodulatory drug that has shown activity in lenalidomide-refractory disease in the setting of different combinations. PATIENTS AND METHODS: A real-world study was conducted by the Spanish Myeloma group in a cohort of patients with RRMM treated with pomalidomide, cyclophosphamide, and dexamethasone (PomCiDex). One hundred patients were treated with a median of 3 prior lines of therapy. RESULTS: Overall response rate was 39%, with a clinical benefit rate of 93%. Median PFS was 7.6 months; median overall survival (OS) was 12.6 months. Median PFS and OS survival were consistent across the different subgroups analyzed. Prolonged PFS and OS were found in patients with responsive disease. CONCLUSION: Our results compared favorably with those obtained with different pomalidomide-based combinations in a similar patient population. PomCiDex remains a manageable, cost-effective, and all-oral triplet combination for RRMM patients.

A phase 3 trial of azacitidine versus a semi-intensive fludarabine and cytarabine schedule in older patients with untreated acute myeloid leukemia.

BACKGROUND: Options to treat elderly patients (≥65 years old) newly diagnosed with acute myeloid leukemia (AML) include intensive and attenuated chemotherapy, hypomethylating agents with or without venetoclax, and supportive care. This multicenter, randomized, open-label, phase 3 trial was designed to assess the efficacy and safety of a fludarabine, cytarabine, and filgrastim (FLUGA) regimen in comparison with azacitidine (AZA). METHODS: Patients (n = 283) were randomized 1:1 to FLUGA (n = 141) or AZA (n = 142). Response was evaluated after cycles 1, 3, 6, and 9. Measurable residual disease (MRD) was assessed after cycle 9. When MRD was ≥0.01%, patients continued with the treatment until relapse or progressive disease. Patients with MRD < 0.01% suspended treatment to enter the follow-up phase. RESULTS: The complete remission (CR) rate after 3 cycles was significantly better in the FLUGA arm (18% vs 9%; P = .04), but the CR/CR with incomplete recovery rate at 9 months was similar (33% vs 29%; P = .41). There were no significant differences between arms in early mortality at 30 or 60 days. Hematologic toxicities were more frequent with FLUGA, especially during induction. The 1-year overall survival (OS) rate and the median OS were superior with AZA versus FLUGA: 47% versus 27% and 9.8 months (95% confidence interval [CI], 5.6-14 months) versus 4.1 months (95% CI, 2.7-5.5 months; P = .005), respectively. The median event-free survival was 4.9 months (95% CI, 2.8-7 months) with AZA and 3 months (95% CI, 2.5-3.5 months) with FLUGA (P = .001). CONCLUSIONS: FLUGA achieved more remissions after 3 cycles, but the 1-year OS rate was superior with AZA. However, long-term outcomes were disappointing in both arms (3-year OS rate, 10% vs 5%). This study supports the use of an AZA backbone for future combinations in elderly patients with AML.

Measurable residual disease in elderly acute myeloid leukemia: results from the PETHEMA-FLUGAZA phase 3 clinical trial.

The value of measurable residual disease (MRD) in elderly patients with acute myeloid leukemia (AML) is inconsistent between those treated with intensive vs hypomethylating drugs, and unknown after semi-intensive therapy. We investigated the role of MRD in refining complete remission (CR) and treatment duration in the phase 3 FLUGAZA clinical trial, which randomized 283 elderly AML patients to induction and consolidation with fludarabine plus cytarabine (FLUGA) vs 5-azacitidine. After consolidation, patients continued treatment if MRD was ≥0.01% or stopped if MRD was <0.01%, as assessed by multidimensional flow cytometry (MFC). On multivariate analysis including genetic risk and treatment arm, MRD status in patients achieving CR (N = 72) was the only independent prognostic factor for relapse-free survival (RFS) (HR, 3.45; P = .002). Achieving undetectable MRD significantly improved RFS of patients with adverse genetics (HR, 0.32; P = .013). Longer overall survival was observed in patients with undetectable MRD after induction though not after consolidation. Although leukemic cells from most patients displayed phenotypic aberrancies vs their normal counterpart (N = 259 of 265), CD34 progenitors from cases with undetectable MRD by MFC carried extensive genetic abnormalities identified by whole-exome sequencing. Interestingly, the number of genetic alterations significantly increased from diagnosis to MRD stages in patients treated with FLUGA vs 5-azacitidine (2.2-fold vs 1.1-fold; P = .001). This study supports MRD assessment to refine CR after semi-intensive therapy or hypomethylating agents, but unveils that improved sensitivity is warranted to individualize treatment and prolong survival of elderly AML patients achieving undetectable MRD.

Treatment of Frail Older Adults and Elderly Patients With Philadelphia Chromosome-negative Acute Lymphoblastic Leukemia: Results of a Prospective Trial With Minimal Chemotherapy.

BACKGROUND: The treatment of acute lymphoblastic leukemia (ALL) in older adults and elderly patients is a challenge, and modern protocols include targeted therapy and immunotherapy in combination with attenuated or minimal chemotherapy. However, frail patients are excluded from these trials, and reports on the outcome of this subgroup of patients are scarce. Our objective was to analyze the outcome of unfit older adults and elderly patients with Philadelphia chromosome-negative ALL included in a prospective trial (ALL-07FRAIL). PATIENTS AND METHODS: Older adults and elderly patients with Charlson Comorbidity Index (CCI) ≥ 4 were included. Induction therapy consisted of vincristine and dexamethasone, and maintenance therapy with mercaptopurine and methotrexate for 2 years. RESULTS: Seventy-two patients with a median age of 67 years (range, 57-89 years) and a median CCI of 5 (range, 4-12) were included. The rates of early withdrawal, early death, resistance, and complete response (CR) were 5%, 10%, 31%, and 54%, respectively. Six patients with CR abandoned the study, 5 died in CR, and 23 relapsed (cumulative relapse incidence 75%). The medians of disease-free and overall survival (OS) were 6.9 months (95% confidence interval [CI], 0.3-13.5 months) and 7.6 months (95% CI, 6.3-8.9 months), respectively. The most frequent toxic events were hematologic (neutropenia 77% and thrombocytopenia 54%, of grade III-IV in all cases). Eastern Cooperative Oncology Group score but not the CCI had significant impact on OS. CONCLUSION: Complete remission with very attenuated chemotherapy can be attained in one-half of older or elderly infirm patients with ALL. These results suggest that some of these patients could benefit from the concomitant or subsequent use of immunotherapy and/or targeted therapy.

Incidence and outcome after first molecular versus overt recurrence in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia included in the ALL Ph08 trial from the Spanish PETHEMA Group.

BACKGROUND: Disease recurrence occurs in 20% to 40% of adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) who are treated with chemotherapy and tyrosine kinase inhibitors (TKIs). In the current study, the authors report the incidence, treatment, and outcome after first disease recurrence in young and older adults treated in the ALL Ph08 trial (ClinicalTrials.gov identifier NCT01491763). METHODS: Patients aged 18 to 55 years with de novo Ph+ ALL were treated with imatinib concurrently with standard-dose induction and consolidation therapy followed by allogeneic hematopoietic stem cell transplantation (allo-HSCT) when possible. In patients with first disease recurrence, the authors analyzed the type of recurrence, timing, location, presence of kinase domain mutations, type of treatment, and outcomes. RESULTS: Of the 125 patients, 28 patients (22%) developed disease recurrence before (4 patients) or after (24 patients) HSCT, with the recurrences being molecular in 11 patients (39%) and overt in 17 patients (61%). T315I was the most common mutation noted at the time of disease recurrence. Change in TKI was the most frequent treatment for patients with molecular disease recurrence whereas rescue chemotherapy and TKI change followed by second allo-HSCT when possible were performed for the most part in patients with overt disease recurrence. A total of 20 patients (71%) achieved response. The median disease-free survival (DFS) and overall survival (OS) were 8.5 months and 15.3 months, respectively. A trend for better DFS and OS was observed in patients with molecular recurrence compared with those with overt recurrence (median of 16.9 months vs 6.3 months [P = .05] and 28.7 months vs 11.5 months [P = .05] for DFS and OS, respectively). CONCLUSIONS: Disease recurrence was frequent in young and older adults with Ph+ ALL who were treated with imatinib and chemotherapy with HSCT. Although the majority of patients responded to rescue therapy, their outcomes were poor, especially with regard to overt disease recurrence.

A precision medicine test predicts clinical response after idarubicin and cytarabine induction therapy in AML patients.

Complete remission (CR) after induction therapy is the first treatment goal in acute myeloid leukemia (AML) patients and has prognostic impact. Our purpose is to determine the correlation between the observed CR/CRi rate after idarubicin (IDA) and cytarabine (CYT) 3 + 7 induction and the leukemic chemosensitivity measured by an ex vivo test of drug activity. Bone marrow samples from adult patients with newly diagnosed AML were included in this study. Whole bone marrow samples were incubated for 48 h in well plates containing IDA, CYT, or their combination. Pharmacological response parameters were estimated using population pharmacodynamic models. Patients attaining a CR/CRi with up to two induction cycles of 3 + 7 were classified as responders and the remaining as resistant. A total of 123 patients fulfilled the inclusion criteria and were evaluable for correlation analyses. The strongest clinical predictors were the area under the curve of the concentration response curves of CYT and IDA. The overall accuracy achieved using MaxSpSe criteria to define positivity was 81%, predicting better responder (93%) than non-responder patients (60%). The ex vivo test provides better yet similar information than cytogenetics, but can be provided before treatment representing a valuable in-time addition. After validation in an external cohort, this novel ex vivo test could be useful to select AML patients for 3 + 7 regimen vs. alternative schedules.

Frequency and prognostic significance of additional cytogenetic abnormalities to the Philadelphia chromosome in young and older adults with acute lymphoblastic leukemia.

About 25-35% of adult patients with acute lymphoblastic leukemia show the Philadelphia (Ph) chromosome. Few series have evaluated the prognosis of additional cytogenetic alterations (ACA) to the Ph chromosome. We analyzed the frequency, type and prognostic significance ofACA in adults (18-60 years) treated in the ALL-Ph-08 trial. Fifty-two out of 74 patients (70%) showed ACA and 19 (26%) presented monosomies associated with t(9;22) (monosomal karyotype, MK). Similar complete response (CR) rate, CR duration, overall survival and event-free survival (EFS) were observed in patients with or without ACA, but patients with MK showed shorter CR duration and EFS than the remaining. On multivariate analysis, the only variable with prognostic impact for CR duration and EFS was the presence of MK (p = .003 and p = .036, respectively). Although ACA associated with the Ph chromosome are frequent, only monosomies were associated with poor prognosis in this group of patients.

Presence of acute and chronic renal failure in patients with paroxysmal nocturnal hemoglobinuria: results of a retrospective analysis from the Spanish PNH Registry.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, life-threatening blood disease. With the advent of eculizumab treatment, renal function has substantially improved, although no data from real-world clinical practice are available. An observational, retrospective, multicenter study was conducted in Spain on clinical data obtained from outpatient visits of patients with PNH (Spanish PNH Registry) who had experienced acute (ARF) or chronic (CRF) renal failure. Of the 128 patients registered (April 2014), 60 were diagnosed with classic PNH. Twenty-seven (45.0%) patients with a mean age of 48.5 (±16.2) years had renal failure, ARF or CRF, and were included in this study. Near half of the patients (n = 13; 48.1%) presented with ARF alone, 33.3% (n = 9) had CRF with episodes of ARF, while 18.5% (n = 5) were diagnosed with CRF alone. For patients with diagnosis of PNH and renal failure (n = 27), the median time to the first ARF episode was 6.5 (CI 95%; 2.2, 14.9) years, whereas the median to the diagnosis of CRF was 14.5 (CI 95%; 3.8, 19.2) years after the diagnosis of PNH. Patients with ARF (n = 22) were treated with eculizumab and did not experience new episodes of ARF, except for one patient with sepsis. Of the patients with CRF, two received treatment without experiencing further episodes of ARF. Sixteen patients who completed treatment (11 with ARF and 5 with ARF + CRF) recovered from the episode of ARF or from CRF. Of the remaining patients treated with eculizumab, one patient improved from stages III to II, three patients stabilized without showing disease progression, and one patient progressed from stages III to IV. Treatment with eculizumab in PNH patients has beneficial effects on renal function, preventing ARF and progression to CRF.

Clinical characteristics of patients with central nervous system relapse in BCR-ABL1-positive acute lymphoblastic leukemia: the importance of characterizing ABL1 mutations in cerebrospinal fluid.

We investigated the frequency, predictors, and evolution of acute lymphoblastic leukemia (ALL) in patients with CNS relapse and introduced a novel method for studying BCR-ABL1 protein variants in cDNA from bone marrow (BM) and cerebrospinal fluid (CSF) blast cells. A total of 128 patients were analyzed in two PETHEMA clinical trials. All achieved complete remission after imatinib treatment. Of these, 30 (23%) experienced a relapse after achieving complete remission, and 13 (10%) had an isolated CNS relapse or combined CNS and BM relapses. We compared the characteristics of patients with and without CNS relapse and further analyzed CSF and BM samples from two of the 13 patients with CNS relapse. In both patients, classical sequencing analysis of the kinase domain of BCR-ABL1 from the cDNA of CSF blasts revealed the pathogenic variant p.L387M. We also performed ultra-deep next-generation sequencing (NGS) in three samples from one of the relapsed patients. We did not find the mutation in the BM sample, but we did find it in CSF blasts with 45% of reads at the time of relapse. These data demonstrate the feasibility of detecting BCR-ABL1 mutations in CSF blasts by NGS and highlight the importance of monitoring clonal evolution over time.

Feasibility and results of subtype-oriented protocols in older adults and fit elderly patients with acute lymphoblastic leukemia: Results of three prospective parallel trials from the PETHEMA group.

BACKGROUND AND OBJECTIVE: The prognosis of acute lymphoblastic leukemia (ALL) is poor in older adults and elderly patients, and subtype-oriented prospective trials are scarce in these patients. We present the results of three prospective parallel subtype-oriented protocols in fit patients older than 55 years. PATIENTS AND METHODS: In 2008, three prospective phase II trials in patients older than 55 years were activated: ALLOLD07 for Philadephia (Ph) chromosome-negative ALL, ALLOPH07 for Ph-positive ALL, and BURKIMAB08 for mature B-ALL. Early death (ED), complete remission (CR), disease-free survival (DFS), overall survival (OS) and toxicity were analyzed. RESULTS: 56, 53 and 21 patients from the ALLOLD07, ALLOPH07 and BURKIMAB08 trials, respectively, were evaluable. CR was 74%, 87% and 70%, with an ED rate of 13%, 11% and 15%, respectively. The medians of DFS were 8 and 38 months for ALLOLD07 and ALLOPH07 protocols, not being achieved in the BURKIMAB08 trial (p=0.001), and the median OS was 12, 37 and 25 months, respectively (p=0.030). Neutropenia, thrombocytopenia and infections were less frequent in the ALLOPH07 trial vs. ALLOLD07 and BURKIMAB trials, and renal toxicity and mucositis were more frequent in the BURKIMAB08 trial vs. the ALLOLD07 and ALLOPH07 trials. ECOG score and WBC count had prognostic significance for OS in ALLOPH07 and BURKIMAB08 trials, whereas no prognostic factors were identified in ALLOLD07 protocol. CONCLUSION: Subtype-oriented treatment had an impact in the outcome of older adults with ALL. The poorest outcome was observed in Ph-negative non-Mature B-cell ALL patients, for whom improvements in therapy are clearly needed.

Pharmacological profiles of acute myeloid leukemia treatments in patient samples by automated flow cytometry: a bridge to individualized medicine.

BACKGROUND: We have evaluated the ex vivo pharmacology of single drugs and drug combinations in malignant cells of bone marrow samples from 125 patients with acute myeloid leukemia using a novel automated flow cytometry-based platform (ExviTech). We have improved previous ex vivo drug testing with 4 innovations: identifying individual leukemic cells, using intact whole blood during the incubation, using an automated platform that escalates reliably data, and performing analyses pharmacodynamic population models. PATIENTS AND METHODS: Samples were sent from 24 hospitals to a central laboratory and incubated for 48 hours in whole blood, after which drug activity was measured in terms of depletion of leukemic cells. RESULTS: The sensitivity of single drugs is assessed for standard efficacy (EMAX) and potency (EC50) variables, ranked as percentiles within the population. The sensitivity of drug-combination treatments is assessed for the synergism achieved in each patient sample. We found a large variability among patient samples in the dose-response curves to a single drug or combination treatment. CONCLUSION: We hypothesize that the use of the individual patient ex vivo pharmacological profiles may help to guide a personalized treatment selection.

Incidence, risk factors, and outcome of bacteremia following autologous hematopoietic stem cell transplantation in 720 adult patients.

Bacteremia is the most frequent infectious complication during neutropenia in patients receiving autologous hematopoietic stem cell transplantation (ASCT). The objective of this study was to analyze the incidence, characteristics, risk factors, and outcome of bacteremia during the early period after ASCT. A total of 720 patients undergoing ASCT in two observational prospective consecutive multicenter studies of the Programa Español para el Tratamiento de las Hemopatías group were analyzed. Bacteremia occurred in 20 % of patients. Coagulase-negative Staphylococcus was the most frequent (66 %) among the gram-positive agents and Escherichia coli (49 %) among the gram-negative agents. Multivariate analysis showed that the length of neutropenia <1 × 10(9)/L (more than 9 days) [relative risk (RR) of 2.6, p < 0.001] was the sole risk factor for overall bacteremia. We identified the length of neutropenia <1 × 10(9)/L (more than 9 days) (RR 4.98, p < 0.001) and the use of prophylactic fluoroquinolones (RR 0.46, p < 0.01) as specific risk factors for gram-negative bacteremia. Risk factors for gram-positive bacteremia were the use of total parenteral nutrition (RR 1.92, p < 0.01) and deep neutropenia (<0.1 × 10(9)/L), with duration over 5 days (RR 1.67, p < 0.027). Bacteremia showed an increased morbidity with no impact on neither overall nor infectious related mortality. The identification of such risk factors may be helpful to implement prophylactic and therapeutic risk-adapted strategies to reduce the incidence of bacteremia in ASCT.

Differences in anti-apoptotic and multidrug resistance phenotypes in elderly and young acute myeloid leukemia patients are related to the maturation of blast cells.

BACKGROUND AND OBJECTIVES: Elderly patients with acute myeloid leukemia (AML) have a less favorable outcome, which has been related, among other factors, to multidrug resistance (MDR) phenotypes. DESIGN AND METHODS: Freshly obtained erythrocyte-lysed bone marrow samples from 150 elderly patients (> 65 years) with de novo AML and 30 younger AML patients were analyzed using a 4-color immunofluorescence technique for quantitative expression of proteins associated with apoptosis (bcl-2, bax, APO2.7) and MDR (P-gp, MRP, LRP) in 3 blast cell subpopulations, defined according to their maturation stage. RESULTS: Although a homogeneous CD34+ blast cell population was more frequent in the elderly patients, (25% vs 7%, p=0.02), no statistically significant differences were detected between the two age groups in the expression of either apoptosis- or MDR-associated proteins, except for slightly higher quantities of LRP protein in the more immature CD34+ blast cell subset in the elderly AML cases (p=0.04). Interestingly, when different blast cell populations were compared, immature (CD34+) blast cells were characterized by higher levels of bcl-2 in both age groups and lower levels of APO2.7 in the elderly group. In addition, higher P-gp levels were found in CD34+ blast cells than in CD34-- ones in elderly AML patients. Reactivity for LRP was low in both elderly and younger patients. INTERPRETATION AND CONCLUSIONS: In summary, our results suggest that the higher resistance to chemotherapy observed in elderly AML patients could be related to a higher incidence of cases with a CD34+ homogeneous blast cell population, since these blast cells frequently display a more pronounced anti-apoptotic and MDR1 phenotype.

CD34+ cells from acute myeloid leukemia, myelodysplastic syndromes, and normal bone marrow display different apoptosis and drug resistance-associated phenotypes.

Myelodysplastic syndromes and acute myeloid leukemia (AML) are heterogeneous disorders in which conflicting results in apoptosis and multidrug resistance (MDR) have been reported. We have evaluated by multiparameter flow cytometry the expression of apoptosis- (APO2.7, bcl-2, and bax) and MDR-related proteins [P-glycoprotein (P-gp), multidrug resistance protein (MRP), and lung resistance protein (LRP)] specifically on bone marrow (BM) CD34+ cells, and their major CD32-/dim and CD32+ subsets, in de novo AML (n=90), high-risk myelodysplastic syndrome (n=9), and low-risk myelodysplastic syndrome (n=21) patients at diagnosis, and compared with normal BM CD34+ cells (n=6). CD34+ myeloid cells from AML and high-risk myelodysplastic syndrome patients displayed higher expression of bcl-2 (P <0.0001) and lower reactivity for APO2.7 (P=0.002) compared with low-risk myelodysplastic syndrome and normal controls. Similar results applied to the two predefined CD34+ myeloid cell subsets. No significant differences were found in the expression of P-gp, MRP, and LRP between low-risk myelodysplastic syndrome patients and normal BM, but decreased expression of MRP (P <0.03) in AML and high-risk myelodysplastic syndromes and P-gp (P=0.008) in high-risk myelodysplastic syndromes were detected. Hierarchical clustering analysis showed that low-risk myelodysplastic syndrome patients were clustered next to normal BM samples, whereas high-risk myelodysplastic syndromes were clustered together and mixed with the de novo AML patients. In summary, increased resistance to chemotherapy of CD34+ cells from both AML and high-risk myelodysplastic syndromes would be explained more appropriately in terms of an increased antiapoptotic phenotype rather than a MDR phenotype. In low-risk myelodysplastic syndromes abnormally high apoptotic rates would be restricted to the CD34- cell compartments.