Infections in patients taking Rituximab for hematologic malignancies: two-year cohort study.

BACKGROUND: Rituximab (R) is a chimeric human-murine anti-CD20 monoclonal antibody used to treat B-cell lymphomas. Despite R remarkable activity against malignant cells, there are concerns that R may facilitate the occurrence of infections. This study is aimed to define risk factors for infections, and the potential interaction with time since therapy, in patients undergoing R containing regimens. METHODS: The study has been designed as a multiple failure events historical cohort including all patients who received a R contain regimen at London Royal Free Hospital between May 2007 and April 2009. RESULT: One-hundred-eighty-one infections occurred among the 113 enrolled patients (overall incidence rate 3.30 per 1000 person-days). Multivariate analysis showed that lymphocyte counts at nadir, graft versus host disease, HIV sero-status and the type of malignancy were all independently associated with the risk of infection. In addition the analysis of the interaction with the time since the start of therapy provided evidence that different risk factors may increase risk of infections in different times. CONCLUSION: This study provides preliminary data to describe the association between several patients' baseline characteristics and infections during therapy with R.

Risk of infection in patients with lymphoma receiving rituximab: systematic review and meta-analysis.

BACKGROUND: The addition of Rituximab (R) to standard chemotherapy (C) has been reported to improve the end of treatment outcome in patients affected by CD-20 positive malignant lymphomas (CD20+ ML). Nevertheless, given the profound and prolonged immunosuppression produced by R there are concerns that severe infections may arise. A systematic review and meta-analysis were performed to determine whether or not the addition of R to C may increase the risk of severe infections in adults undergoing induction therapy for CD20+ ML. METHODS: Only randomised controlled trials comparing R-C to C standard alone in adult patients with CD20+ ML were included. Meta-analysis was performed on overall incidence of severe infection, risk of dying as the consequence of infection, risk of febrile neutropenia, risk of severe leucopenia, risk of severe granulocytopenia and overall response assuming a fixed effect model. Heterogeneity was investigated, if present and I2 >20%, according to several predefined baseline characteristics of the study populations. RESULTS: Several relevant results have emerged. First, the addition of R to standard C does not increase the overall risk of severe infections (RR = 1.00; 95% CI 0.87 to 1.14) nor does it increase the risk of dying as a consequence of infection (RR = 1.60; 95% CI 0.68 to 3.75). Second, we confirmed that the addition of R to standard C increases the proportion of overall response (RR = 1.12; 95% CI 1.09 to 1.15), but it also increases the risk of severe leucopenia (RR = 1.24; 95% CI 1.12 to 1.37) and granulocytopenia (RR = 1.07; 95% CI 1.02 to 1.12). CONCLUSIONS: R-C is superior to standard C in terms of overall response and it does not increase the overall incidence of severe infection. However, data on special groups of patients (for example, HIV positive subjects and HBV carriers) are lacking. In our opinion more studies are needed to explore the potential effect of R on silent and chronic viral infections.

Aberrantly activated anti-apoptotic signalling mechanisms in chronic lymphocytic leukaemia cells: clues to the identification of novel therapeutic targets.

Chronic lymphocytic leukaemia (CLL) is the commonest haematological malignancy in the western world and is incurable by cytotoxic therapy. Considerable research effort has identified the signal transduction pathways in CLL cells that contribute to anti-apoptotic signalling. Some pathways are constitutively activated in CLL cells but upregulated in normal cells only when protein tyrosine kinases (PTKs) are activated by ligands. This review describes which PTKs are aberrantly activated in CLL cells and are potential targets for inhibition. Additional potential targets within pathways downstream of these PTKs include Mek/Erk, mTorc1, protein kinase C, PI-3 kinase/Akt, nuclear factor-κB and cyclin-dependent protein kinase. Numerous studies have identified chemical agents and antibodies that selectively kill CLL cells, irrespective of their genetic resistance to conventional chemotherapeutic agents, and which can overcome cytoprotective microenvironmental signalling. These studies have resulted in identification of novel therapies, some of which are currently undergoing clinical trials. In vitro and animal model studies and clinical trials could determine which inhibitors of which targets are the likely to be most effective and least toxic either singly or in combination.

The JAK3-selective inhibitor PF-956980 reverses the resistance to cytotoxic agents induced by interleukin-4 treatment of chronic lymphocytic leukemia cells: potential for reversal of cytoprotection by the microenvironment.

Extensive evidence suggests that the malignant cells of chronic lymphocytic leukemia (CLL) patients are in close contact with activated T lymphocytes, which secrete a range of cytoprotective cytokines including interleukin-4 (IL-4). IL-4 induced the rapid phosphorylation and activation of the signal transducer and activator of transcription 6 transcription factor in CLL cells in vitro. Longer incubation with IL-4 resulted in up-regulation of the antiapoptotic proteins, Mcl-1 and Bcl-X(L). All of these events were blocked by the JAK3-selective inhibitor, PF-956980. A dye reduction cytotoxicity assay showed that IL-4 induced resistance to the cytotoxic drugs fludarabine and chlorambucil and to the novel p53-elevating agent nutlin 3. IL-4-induced drug resistance was reversed by PF-956980. These conclusions were confirmed by independent assays for apoptosis induction (annexin V binding, cleavage of poly[ADP-ribose] polymerase, and morphologic analysis). Coculture with bone marrow stromal cells in the presence of supernatants derived from activated T-lymphocyte cultures also protected CLL cells from apoptosis induction by chlorambucil. Protection by these combined signals was reversed by PF-956980. The data here provide a preclinical rationale for the possible therapeutic use of PF-956980 in conjunction with conventional cytotoxic drugs to achieve more extensive killing of CLL cells by overcoming antiapoptotic signaling by the microenvironment.

The impact on outcome of the addition of all-trans retinoic acid to intensive chemotherapy in younger patients with nonacute promyelocytic acute myeloid leukemia: overall results and results in genotypic subgroups defined by mutations in NPM1, FLT3, and CEBPA.

We investigated the benefit of adding all-trans retinoic acid (ATRA) to chemotherapy for younger patients with nonacute promyelocytic acute myeloid leukemia and high-risk myelodysplastic syndrome, and considered interactions between treatment and molecular markers. Overall, 1075 patients less than 60 years of age were randomized to receive or not receive ATRA in addition to daunorubicin/Ara-C/thioguanine chemotherapy with Ara-C at standard or double standard dose. There were data on FLT3 internal tandem duplications and NPM1 mutations (n = 592), CEBPA mutations (n = 423), and MN1 expression (n = 195). The complete remission rate was 68% with complete remission with incomplete count recovery in an additional 16%; 8-year overall survival was 32%. There was no significant treatment effect for any outcome, with no significant interactions between treatment and demographics, or cytarabine randomization. Importantly, there were no interactions by FLT3/internal tandem duplications, NPM1, or CEBPA mutation. There was a suggestion that ATRA reduced relapse in patients with lower MN1 levels, but no significant effect on overall survival. Results were consistent when restricted to patients with normal karyotype. ATRA has no overall effect on treatment outcomes in this group of patients. The study did not identify any subgroup of patients likely to derive a significant survival benefit from the addition of ATRA to chemotherapy.

Attempts to optimize induction and consolidation treatment in acute myeloid leukemia: results of the MRC AML12 trial.

PURPOSE: To optimize treatment for younger patients with acute myeloid leukemia and high-risk myelodysplastic syndrome by comparing induction options and the number of consolidation courses and whether consolidation should include transplantation. PATIENTS AND METHODS: We randomly assigned 1,658 patients younger than age 60 years to receive mitoxantrone/cytarabine/etoposide versus cytarabine/daunorubicin/etoposide and subsequently 1,193 patients to daunorubicin/cytarabine/thioguanine (DAT) where the cytarabine dose was standard (S-DAT) versus double the standard dose (H-DAT). Patients in this randomization were randomly assigned to all-trans-retinoic acid or not. In consolidation, 992 patients were randomly assigned between a total of four courses versus five courses, and 324 patients who were not good risk were randomly assigned to transplantation or chemotherapy as the final course. RESULTS: Complete remission (CR) was achieved in 74% of patients and CR without recovery was achieved in an additional 11%; overall survival (OS) at 8 years was 38%. No differences in CR, relapse-free survival, relapse, or OS were seen between any of the induction randomizations except for a reduction in relapse risk (RR) on the mitoxantrone arm, which was offset by increased myelosuppression and deaths in CR. The addition of a fifth course did not improve OS and may be detrimental in older patients. Although transplantation reduced RR, it did not improve OS for the intermediate-risk group but was probably of benefit in high-risk patients. CONCLUSION: Several chemotherapy schedules achieved similar remission rates and OS. Four courses of chemotherapy are adequate, but the addition of transplantation as a final course does not improve OS. New agents are required to enhance conventional chemotherapy.

2-Phenylacetylenesulfonamide (PAS) induces p53-independent apoptotic killing of B-chronic lymphocytic leukemia (CLL) cells.

We studied the actions of 2-phenylacetylenesulfonamide (PAS) on B-chronic lymphocytic leukemia (CLL) cells. PAS (5-20 microM) initiated apoptosis within 24 hours, with maximal death at 48 hours asassessed by morphology, cleavage of poly(ADP-ribose) polymerase (PARP), caspase 3 activation, and annexin V staining. PAS treatment induced Bax proapoptotic conformational change, Bax movement from the cytosol to the mitochondria, and cytochrome c release, indicating that PAS induced apoptosis via the mitochondrial pathway. PAS induced approximately 3-fold up-regulation of proapoptotic Noxa protein and mRNA levels. In addition, Noxa was found unexpectedly to be bound to Bcl-2 in PAS-treated cells. PAS treatment of CLL cells failed to up-regulate p53, suggesting that PAS induced apoptosis independently of p53. Furthermore, PAS induced apoptosis in CLL isolates with p53 gene deletion in more than 97% of cells. Normal B lymphocytes were as sensitive to PAS-induced Noxa up-regulation and apoptosis as were CLL cells. However, both T lymphocytes and bone marrow hematopoietic progenitor cells were relatively resistant to PAS. Our data suggest that PAS may represent a novel class of drug that induces apoptosis in CLL cells independently of p53 status by a mechanism involving Noxa up-regulation.

Prognostic factor analysis of the survival of elderly patients with AML in the MRC AML11 and LRF AML14 trials.

This analysis, of 2483 patients with acute myeloid leukaemia (AML) aged 60+ years entered into two UK trials, was performed to determine the baseline parameters related to survival and to develop a risk index. The Medical Research Council (MRC) AML11 trial (n = 1071) was used to develop the index; this was validated using data from the Leukaemia Research fund (LRF) AML14 trial on 1137 intensively (AML14I) and 275 non-intensively (AML14NI) treated patients. In AML11, cytogenetic group, age, white blood count, performance status and type of AML (de novo, secondary) were all highly significantly related to prognosis in multivariate analysis. The regression coefficients were used to define good, standard and poor risk groups, with 1-year survival of 53%, 43% and 16% respectively (P < 0.0001). The risk index showed very good discrimination in both AML14I and AML14NI (both P < 0.0001), thereby providing validation, although survival in all groups was very poor in AML14NI. The risk factors for survival in older AML patients were similar to those in younger ones and discrimination of patient groups with relatively good to very poor prognosis was possible. These risk groups apply to both intensively and non-intensively treated patients. Randomized trials of intensive versus non-intensive therapy are needed to determine which types of patient should be given which type of treatment.

The impact of dose escalation and resistance modulation in older patients with acute myeloid leukaemia and high risk myelodysplastic syndrome: the results of the LRF AML14 trial.

The acute myeloid leukaemia (AML)14 trial addressed four therapeutic questions in patients predominantly aged over 60 years with AML and High Risk Myelodysplastic Syndrome: (i) Daunorubicin 50 mg/m(2) vs. 35 mg/m(2); (ii) Cytarabine 200 mg/m(2) vs. 400 mg/m(2) in two courses of DA induction; (iii) for part of the trial, patients allocated Daunorubicin 35 mg/m(2) were also randomized to receive, or not, the multidrug resistance modulator PSC-833 in a 1:1:1 randomization; and (iv) a total of three versus four courses of treatment. A total of 1273 patients were recruited. The response rate was 62% (complete remission 54%, complete remission without platelet/neutrophil recovery 8%); 5-year survival was 12%. No benefits were observed in either dose escalation randomization, or from a fourth course of treatment. There was a trend for inferior response in the PSC-833 arm due to deaths in induction. Multivariable analysis identified cytogenetics, presenting white blood count, age and secondary disease as the main predictors of outcome. Although patients with high Pgp expression and function had worse response and survival, this was not an independent prognostic factor, and was not modified by PSC-833. In conclusion, these four interventions have not improved outcomes in older patients. New agents need to be explored and novel trial designs are required to maximise prospects of achieving timely progress.

p53-mediated apoptosis of CLL cells: evidence for a transcription-independent mechanism.

The p53 protein plays a key role in securing the apoptotic response of chronic lymphocytic leukemia (CLL) cells to genotoxic agents. Transcriptional induction of proapoptotic proteins including Puma are thought to mediate p53-dependent apoptosis. In contrast, recent studies have identified a novel nontranscriptional mechanism, involving direct binding of p53 to antiapoptotic proteins including Bcl-2 at the mitochondrial surface. Here we show that the major fraction of p53 induced in CLL cells by chlorambucil, fludarabine, or nutlin 3a was stably associated with mitochondria, where it binds to Bcl-2. The Puma protein, which was constitutively expressed in a p53-independent manner, was modestly up-regulated following p53 induction. Pifithrin alpha, an inhibitor of p53-mediated transcription, blocked the up-regulation of Puma and also of p21(CIP1). Surprisingly, pifithrin alpha dramatically augmented apoptosis induction by p53-elevating agents and also accelerated the proapoptotic conformation change of the Bax protein. These data suggest that direct interaction of p53 with mitochondrial antiapoptotic proteins including Bcl-2 is the major route for apoptosis induction in CLL cells and that p53's transcriptional targets include proteins that impede this nontranscriptional pathway. Therefore, strategies that block up-regulation of p53-mediated transcription may be of value in enhancing apoptosis induction of CLL cells by p53-elevating drugs.

ZAP-70 expression is associated with enhanced ability to respond to migratory and survival signals in B-cell chronic lymphocytic leukemia (B-CLL).

Molecular markers like IgV(H) mutational status, chromosomal abnormalities, and CD38 and ZAP-70 expression have prognostic value in B-cell chronic lymphocytic leukemia (B-CLL). These may be pathogenetic because of the coincidental expression of ZAP-70 and increased B-cell receptor (BCR) signaling and the signaling function of CD38 in CLL. This study shows that ZAP-70(+) CLL B cells respond in vitro more readily than ZAP-70(-) CLL and normal B cells to chemokine migratory signals through enhanced surface CCR7 expression (P = .009; P < .001) and increased responsiveness to its ligands CCL19 and CCL21, demonstrated by F-actin polymerization (P < .05) and cellular migration (P < .01). In addition, ZAP-70(+) CLL cells exhibit sustained ERK phosphorylation/activation following stimulation with CXCL12 (SDF1-alpha, a survival factor produced by stromal cells) compared with ZAP-70(-) cells (P = .004). Following coculture with nurse-like cells, the survival of ZAP-70(+) but not ZAP-70(-) CLL cells is significantly enhanced by the addition of CXCL12 (P < .05), an effect that is partially blocked by the MEK inhibitor PD98059. These advantageous migratory and survival responses may promote easier access to and greater proliferation in pseudo-germinal centers and explain in part the more progressive nature of ZAP-70(+) disease.

Making sense of itraconazole pharmacokinetics.

The triazole, itraconazole, has a wide spectrum of antifungal activity in vitro. Confirming this activity in vivo has been a long and difficult task because of problems with formulation, delivery and uncertainty about effective bioavailability. The physicochemical properties of the drug make it insoluble in water but strongly protein bound. The absorption and blood levels of the original capsular formulation were predictable with non-linear, saturation kinetics in normal volunteers. Tissue penetration was high and sustained. In neutropenic patients with haematological malignancies, levels were very variable and the doses required to achieve effective antifungal levels were higher than predicted from normal subjects' results. The solubility of the drug and predictability of blood levels were improved by the formulation of an oral solution with cyclodextrin. Wash-out times were prolonged in patients with this new formulation implying that tissue penetration was maintained. A high volume of distribution suggests that loading may be necessary. An intravenous cyclodextrin solution is also now available allowing rapid loading and avoidance of the well-known gut side effects of the oral solution. Clinical studies have suggested minimum bioavailable dosage and minimum trough blood levels for effective prophylaxis against systemic fungal infection. Interactions are also now well documented and manageable. The drug can be measured reliably, quickly and comparatively cheaply by HPLC in serum and plasma. The frequency of such testing in clinical practice depends on the need to ensure adequate levels and to avoid unwanted toxicity.

Evidence-based review of antifungal prophylaxis in neutropenic patients with haematological malignancies.

BACKGROUND: There is still no consensus on the efficacy of antifungal prophylaxis in neutropenic patients after more than 50 clinical trials. METHODS: This review evaluates the current evidence from all available meta-analyses of the use of intravenous amphotericin B, fluconazole and itraconazole for this indication. RESULTS: Four systematic reviews with meta-analysis and one evidence-based review without meta-analysis were evaluated. Efficacy of fluconazole has been shown on short-term follow-up after allogeneic stem cell transplantation but only itraconazole was effective in neutropenic patients with haematological malignancies for prolonged prophylaxis after allogeneic stem cell transplantation. Direct comparison between fluconazole and itraconazole for this indication shows the superiority of itraconazole which was the only drug able to prevent invasive Aspergillus infections in our previously published meta-analysis of 13 trials and 3597 patients. Efficacy of itraconazole correlates closely with its dose; an effect was seen only in clinical trials using at least 400 mg/day oral solution or 200 mg/day intravenous solution. With this dose, invasive fungal infections were reduced by 53% and mortality from invasive fungal infections was reduced by 47% (P<0.05). Toxicity of itraconazole is rare and usually not severe and drug interactions are easily manageable. CONCLUSIONS: Itraconazole is recommended for antifungal prophylaxis in high-risk neutropenic patients with haematological malignancies or for prolonged prophylaxis after allogeneic stem cell transplantation based on unambiguous evidence of efficacy and low toxicity from clinical trials and systematic reviews.

Itraconazole prevents invasive fungal infections in neutropenic patients treated for hematologic malignancies: evidence from a meta-analysis of 3,597 patients.

PURPOSE: Efficacy of antifungal prophylaxis has not yet been convincingly proven in numerous trials of various antifungals. New evidence and the anti-Aspergillus efficacy of itraconazole prompted a new look at the data for the prevention of invasive fungal infections. PATIENTS AND METHODS: Randomized, controlled studies with itraconazole for antifungal prophylaxis in neutropenic patients with hematologic malignancies were identified from electronic databases and hand searching. RESULTS: Thirteen randomized trials included 3,597 patients who were assessable for invasive fungal infections. Itraconazole reduced the incidence of invasive fungal infection (mean relative risk reduction, 40% +/- 13%; P =.002), the incidence of invasive yeast infections (mean, 53% +/- 19%; P =.004) and the mortality from invasive fungal infections (mean, 35% +/- 17%; P =.04) significantly. The incidence of invasive Aspergillus infections was only reduced in trials using the itraconazole cyclodextrine solution (mean, 48% +/- 21%; P =.02) and not itraconazole capsules (mean, 75% +/- 73% increase; P =.3). The overall mortality was not changed. Adverse effects were rare, hypokalemia was noted in three studies, and a higher rate of drug discontinuation was found in trials that compared itraconazole cyclodextrine solution to a control without cyclodextrine. The effect of prophylaxis was clearly associated with a higher bioavailable dose of itraconazole. CONCLUSION: Antifungal prophylaxis with itraconazole effectively prevents proven invasive fungal infections and-shown for the first time for antifungal prophylaxis-reduces mortality from these infections and the rate of invasive Aspergillus infections in neutropenic patients with hematologic malignancies. Adequate doses of the oral cyclodextrine solution (at least 400 mg/d) or i.v. formulations (200 mg/d) of itraconazole are necessary for these effects.