MIPSS70+ v2.0 predicts long-term survival in myelofibrosis after allogeneic HCT with the Flu/Mel conditioning regimen.

Although allogeneic hematopoietic cell transplantation (allo-HCT) is the only curative treatment for myelofibrosis (MF), data are limited on how molecular markers predict transplantation outcomes. We retrospectively evaluated transplantation outcomes of 110 consecutive MF patients who underwent allo-HCT with a fludarabine/melphalan (Flu/Mel) conditioning regimen at our center and assessed the impact of molecular markers on outcomes based on a 72-gene next-generation sequencing panel and Mutation-Enhanced International Prognostic Scoring System 70+ v2.0 (MIPSS70+ v2.0). With a median follow-up of 63.7 months, the 5-year overall survival (OS) rate was 65% and the nonrelapse mortality (NRM) rate was 17%. In mutational analysis, JAK2 V617F and ASXL1 mutations were the most common. By univariable analysis, higher Dynamic International Prognostic Scoring System scores, unrelated donor type, and very-high-risk cytogenetics were significantly associated with lower OS. Only CBL mutations were significantly associated with lower OS (hazard ratio [HR], 2.64; P = .032) and increased NRM (HR, 3.68; P = .004) after allo-HCT, but CALR, ASXL1, and IDH mutations did not have an impact on transplantation outcomes. Patient classification per MIPSS70 showed worse OS for high-risk (HR, 0.49; P = .039) compared with intermediate-risk patients. Classification per MIPSS70+ v2.0 demonstrated better OS when intermediate-risk patients were compared with high-risk patients (HR, 0.291) and much lower OS when very-high-risk patients were compared with high-risk patients (HR, 5.05; P ≤ .001). In summary, we present one of the largest single-center experiences of Flu/Mel-based allo-HCT, demonstrating that revised cytogenetic changes and MIPSS70+ v2.0 score predict transplantation outcomes, and thus can better inform physicians and patients in making decisions about allo-HCT.

Using Gold Nanoparticles as Delivery Vehicles for Targeted Delivery of Chemotherapy Drug Fludarabine Phosphate to Treat Hematological Cancers.

Nanotechnology is an emerging paradigm for creating functional nanoscale materials for various biomedical applications. In this study, a new nanotechnology-based drug delivery method was developed using gold nanoparticles (GNPs) as a delivery vehicle to reduce adverse drug side effects. Fludarabine Phosphate is a commercial chemotherapy drug used in cancer treatment, and has ability to kill various cancer cells. KG-1 cell, a type of acute cancer leukemia cell, was selected as a proof-of-concept target in this study. Due to the small size of GNPs, they can help Fludarabine Phosphate enter cancer cells more efficiently and better interfere with DNA synthesis in the cancer cells. To enhance targeting ability, folic acid molecules were also covalently linked to GNPs, resulting in GNP-Fludarabine-folic acid (GNP-F/f). Compared to treatments with GNP-F or drugs on its own (Fludarabine Phosphate), the GNP-F/f achieves much improved cell-killing effects. The UV-Vis spectra results also revealed that the drugs had successfully bonded covalently to the GNPs. The higher cell-killing efficiency of GNP-F/f compared with GNP-Fludarabine (GNP-F) or drugs on their own further validates the effectiveness of both the vectors (GNPs) and folic acid in enhancing the drug delivery to the cancer cells. The MTT viability tests showed that the GNPs had no cytotoxicity.

Activation of multiple chemotherapeutic prodrugs by the natural enzymolome of tumour-localised probiotic bacteria.

Some chemotherapeutic drugs (prodrugs) require activation by an enzyme for efficacy. We and others have demonstrated the ability of probiotic bacteria to grow specifically within solid tumours following systemic administration, and we hypothesised that the natural enzymatic activity of these tumour-localised bacteria may be suitable for activation of certain such chemotherapeutic drugs. Several wild-type probiotic bacteria; Escherichia coli Nissle, Bifidobacterium breve, Lactococcus lactis and Lactobacillus species, were screened against a panel of popular prodrugs. All strains were capable of activating at least one prodrug. E. coli Nissle 1917 was selected for further studies because of its ability to activate numerous prodrugs and its resistance to prodrug toxicity. HPLC data confirmed biochemical transformation of prodrugs to their toxic counterparts. Further analysis demonstrated that different enzymes can complement prodrug activation, while simultaneous activation of multiple prodrugs (CB1954, 5-FC, AQ4N and Fludarabine phosphate) by E. coli was confirmed, resulting in significant efficacy improvement. Experiments in mice harbouring murine tumours validated in vitro findings, with significant reduction in tumour growth and increase in survival of mice treated with probiotic bacteria and a combination of prodrugs. These findings demonstrate the ability of probiotic bacteria, without the requirement for genetic modification, to enable high-level activation of multiple prodrugs specifically at the site of action.

Drug repurposing identifies a synergistic combination therapy with imatinib mesylate for gastrointestinal stromal tumor.

Gastrointestinal stromal tumor (GIST) is a rare and therefore often neglected disease. Introduction of the kinase inhibitor imatinib mesylate radically improved the clinical response of patients with GIST; however, its effects are often short-lived, with GISTs demonstrating a median time-to-progression of approximately two years. Although many investigational drugs, approved first for other cancers, have been subsequently evaluated for the management of GIST, few have greatly affected the overall survival of patients with advanced disease. We employed a novel, focused, drug-repurposing effort for GIST, including imatinib mesylate-resistant GIST, evaluating a large library of FDA-approved drugs regardless of current indication. As a result of the drug-repurposing screen, we identified eight FDA-approved drugs, including fludarabine phosphate (F-AMP), that showed synergy with and/or overcame resistance to imatinib mesylate. F-AMP induces DNA damage, Annexin V, and caspase-3/7 activities as the cytotoxic effects on GIST cells, including imatinib mesylate-resistant GIST cells. F-AMP and imatinib mesylate combination treatment showed greater inhibition of GIST cell proliferation when compared with imatinib mesylate and F-AMP alone. Successful in vivo experiments confirmed the combination of imatinib mesylate with F-AMP enhanced the antitumor effects compared with imatinib mesylate alone. Our results identified F-AMP as a promising, repurposed drug therapy for the treatment of GISTs, with potential to be administered in combination with imatinib mesylate or for treatment of imatinib mesylate-refractory tumors.

A pilot pharmacologic biomarker study in HLA-haploidentical hematopoietic cell transplant recipients.

PURPOSE: Eleven patients diagnosed with various hematologic malignancies receiving an HLA-haploidentical hematopoietic cell transplant (HCT) participated in an ancillary biomarker trial. The goal of the trial was to evaluate potential pharmacologic biomarkers pertinent to the conditioning regimen [fludarabine monophosphate (fludarabine) and cyclophosphamide (CY)] or postgrafting immunosuppression [CY and mycophenolate mofetil (MMF)] in these patients. METHODS: We characterized the interpatient variability of nine pharmacologic biomarkers. The biomarkers evaluated were relevant to fludarabine (i.e., area under the curve (AUC) of 2-fluoro-ara-A or F-ara-A), CY (i.e., AUCs of CY and four of its metabolites), and MMF (i.e., total mycophenolic acid (MPA) AUC, unbound MPA AUC, and inosine monophosphate dehydrogenase (IMPDH) activity). RESULTS: Interpatient variability in the pharmacologic biomarkers was high. Among those related to HCT conditioning, the interpatient variability ranged from 1.5-fold (CY AUC) to 4.0-fold (AUC of carboxyethylphosphoramide mustard, a metabolite of CY). Among biomarkers evaluated as part of postgrafting immunosuppression, the interpatient variability ranged from 1.7-fold (CY AUC) to 4.9-fold (IMPDH area under the effect curve). There was a moderate correlation (R (2) = 0.441) of within-patient 4-hydroxycyclophosphamide formation clearance. CONCLUSIONS: Considerable interpatient variability exists in the pharmacokinetic and drug-specific biomarkers potentially relevant to clinical outcomes in HLA-haploidentical HCT recipients. Pharmacodynamic studies are warranted to optimize the conditioning regimen and postgrafting immunosuppression administered to HLA-haploidentical HCT recipients.

In vivo antitumor activity of intratumoral fludarabine phosphate in refractory tumors expressing E. coli purine nucleoside phosphorylase.

PURPOSE: Systemically administered fludarabine phosphate (F-araAMP) slows growth of human tumor xenografts that express Escherichia coli purine nucleoside phosphorylase (PNP). However, this treatment has been limited by the amount of F-araAMP that can be administered in vivo. The current study was designed to (1) determine whether efficacy of this overall strategy could be improved by intratumoral administration of F-araAMP, (2) test enhancement of the approach with external beam radiation, and (3) optimize recombinant adenovirus as a means to augment PNP delivery and bystander killing in vivo. METHODS: The effects of systemic or intratumoral F-araAMP in mice were investigated with human tumor xenografts (300 mg), in which 10 % of the cells expressed E. coli PNP from a lentiviral promoter. Tumors injected with an adenoviral vector expressing E. coli PNP (Ad/PNP; 2 × 10(11) viral particles, 2 times per day × 3 days) and the impact of radiotherapy on tumors treated by this approach were also studied. Radiolabeled F-araAMP was used to monitor prodrug activation in vivo. RESULTS: Intratumoral administration of F-araAMP in human tumor xenografts expressing E. coli PNP resulted in complete regressions and/or prolonged tumor inhibition. External beam radiation significantly augmented this effect. Injection of large human tumor xenografts (human glioma, nonsmall cell lung cancer, or malignant prostate tumors) with Ad/PNP followed by intratumoral F-araAMP resulted in excellent antitumor activity superior to that observed following systemic administration of prodrug. CONCLUSION: Activation of F-araAMP by E. coli PNP results in destruction of large tumor xenografts in vivo, augments radiotherapy, and promotes robust bystander killing. Our results indicate that intratumoral injection of F-araAMP leads to ablation of tumors in vivo with minimal toxicity.

A pilot pharmacologic biomarker study of busulfan and fludarabine in hematopoietic cell transplant recipients.

PURPOSE: Sixteen patients diagnosed with various hematologic malignancies participated in a phase II study evaluating the addition of rabbit antithymocyte globulin (rATG, Thymoglobulin(®)) to the hematopoietic cell transplant (HCT) conditioning regimen of IV fludarabine monophosphate (fludarabine) and targeted intravenous (IV) busulfan (fludarabine/(T)busulfan). Our goal was to evaluate pharmacologic biomarkers pertinent to both medications in these patients. METHODS: We characterized the interpatient variability of pharmacologic biomarkers relevant to busulfan, specifically busulfan concentration at steady state, and fludarabine, specifically F-ara-A area under the curve (AUC) and fludarabine triphosphate (F-ara-ATP) intracellular accumulation and concentration in separate CD4(+) and CD8(+) T-lymphocyte populations. RESULTS: Acute and chronic graft versus host disease (GvHD) occurred in 11 patients and one patient, respectively. Four patients died before day +100 of non-relapse causes, which met the protocol stopping guidelines. The cumulative incidence of relapse was 25% at 3 year post-HCT. Interpatient variability in the busulfan- and fludarabine-relevant pharmacologic biomarkers was 2.1- to 2.5-fold. F-ara-A AUC and accumulated F-ara-ATP in CD8(+) cells had the highest hazard ratio for non-relapse mortality and overall survival, respectively. However, neither achieved statistical significance. CONCLUSIONS: The low rates of GvHD, particularly in its chronic form, were encouraging, and further biomarker studies are warranted to optimize the fludarabine/(T)busulfan/rATG conditioning regimen.

Phase I trial of 7-hydroxystaurosporine and fludararbine phosphate: in vivo evidence of 7-hydroxystaurosporine induced apoptosis in chronic lymphocytic leukemia.

This is a phase I study of 7-hydroxystaurosporine (UCN-01) and fludararbine monophosphate (FAMP) in relapsed lymphoma. UCN-01 alone was administered in cycle 1 and with FAMP in cycles 2-6. FAMP was escalated in cohorts from 1 to 5 days. UCN-01 and FAMP pharmacokinetics and apoptosis of malignant lymphocytes was evaluated. Eighteen patients were enrolled. Standard FAMP with UCN-01 was tolerated without dose-limiting toxicity (DLT) and those seen were common to either agent alone. One patient died due to Stevens-Johnson syndrome. Seven of 18 patients responded. No pharmacological effect of UCN-01 by FAMP was noted. Lymphocytosis occurred in 15 of 18 patients following UCN-01 to paradoxically increase circulating tumor cells. UCN-01 induced apoptosis in six of eight patients with chronic lymphocytic leukemia (CLL). UCN-01 does not increase FAMP toxicity. Transient lymphocytosis followed by apoptosis occurs with UCN-01. Mobilization from tissue reservoirs may play a role in the induction of cell death in malignant lymphocytes.

Cytotoxic activity of 2-Fluoro-ara-AMP and 2-Fluoro-ara-AMP-loaded erythrocytes against human breast carcinoma cell lines.

Fludarabine phosphate (2-Fluoro-ara-AMP) is a purine analogue approved for the clinical treatment of haematological malignancies. This antimetabolite has also shown 'in vitro' antiproliferative activity against experimental models of solid mammary tumor. In this perspective, we have determined the cytotoxic effects of 2-Fluoro-ara-AMP against two human breast cancer cell lines (the ER-positive MCF-7 and the ER-negative MDA-MB-435), by adding the drug both in its free form and encapsulated into erythrocytes, as a strategy to modify the pharmacokinetic profile of the compound in order to increase its efficacy and decrease its toxicity. Similar antiproliferative activity of 2-Fluoro-ara-AMP in the two cell lines was obtained, reaching an almost complete abrogation of growth already after just 24 h of free drug exposure at all the tested doses. Meanwhile, encapsulated 2-Fluoro-ara-AMP was successfully released from erythrocytes into the culture media in a time-dependent manner with an efficacy comparable to that of the free drug treatment. This result suggests the possibility of administering 2-Fluoro-ara-AMP in patients with breast cancer using autologous erythrocytes as a system to slowly and constantly deliver 2-Fluoro-ara-A into circulation. In addition, possible mechanisms involved in the antiproliferative activity of 2-Fluoro-ara-AMP, such as the effects on cell cycle progression, p53 expression and STAT1 pathway activation in ER+ and ER- cancer cell lines, are proposed.

[Successful treatment of T-cell prolymphocytic leukemia (T-PLL) with fludarabine monophosphate].

We report a 79-year-old woman with T-cell prolymphocytic leukemia (T-PLL) who was successfully treated with fludarabine monophosphate. She was admitted to our hospital because of dyspnea on effort. On admission, anemia and hepatosplenomegaly were apparent but lymphadenopathy was absent. Peripheral blood examination showed anemia and leukocytosis with 29.5% abnormal lymphocytes. The bone marrow was infiltrated with 84.1% abnormal lymphocytes. The nucleolus was visible in some of these abnormal cells. These cells were positive for CD2, CD3, CD4, CD5, CD7, CD38, CD52, and negative for CD8, CD10, CD19, CD20, CD25, CD56. Based on these findings, she was diagnosed as having T-PLL. Therapy with oral cyclophosphamide (50 mg/day) was started, but was discontinued because of agranulocytosis. Then, she received intravenous fludarabine monophosphate (30 mg/day) on days 1-5 every four to five weeks. The reticulocyte count increased gradually, and she became free from red cell transfusions. Unfortunately, she finally died from massive gastro intestinal hemorrhage, but T-PLL was well controlled at the time of death.

[Cost-reduction analysis for oral versus intravenous fludarabine (Beneflur) in Spain]. / Análisis de minimización de costes de fludarabina (Beneflur) oral vs. vía intravenosa en España.

INTRODUCTION: Various international studies have shown that fludarabine is effective, safe, and efficient for treating B-cell chronic lymphocytic leukemia (B-CLL). The purpose of the present study was to carry out a cost-minimization analysis for two alternative forms of fludarabine (oral and intravenous) used to treat B-CLL in Spain. METHODS: The presence of clinical evidence about the treatment equivalence of the two options being compared (oral fludarabine vs. intravenous fludarabine) led us to carry out a cost-minimization analysis. A pharmacoeconomic model was constructed to compile data from the literature and experts' opinions in order to determine the use of health resources associated with the treatment; unit costs were obtained from Spanish databases. The analysis contemplated two perspectives: that of the national health service, which includes only direct health costs, and the social perspective, which also includes the indirect costs that result from loss of productivity. RESULTS: Although fludarabine in its oral form has a higher purchase price than generic intravenous fludarabine does, increased administration costs for the latter, which is used in hospitals, mean that oral fludarabine use produces total savings of euro1,908 and euro1,292 for single-drug therapy and combined therapy with cyclophosphamide, respectively. Including indirect costs increased the savings associated with the oral form of the drug. CONCLUSIONS: In B-CLL patients, treatment with oral fludarabine has a lower cost than treatment with intravenous fludarabine, in both single-drug therapy and combined therapy. Various sensitivity analyses confirmed these results and showed that oral fludarabine should be the treatment of choice for B-CLL in Spain, unless contrain.

A limited sampling schedule to estimate individual pharmacokinetic parameters of fludarabine in hematopoietic cell transplant patients.

PURPOSE: Fludarabine monophosphate (fludarabine) is frequently administered to patients receiving a reduced-intensity conditioning regimen for allogeneic hematopoietic cell transplant (HCT) in an ambulatory care setting. These patients experience significant interpatient variability in clinical outcomes, potentially due to pharmacokinetic variability in 2-fluoroadenine (F-ara-A) plasma concentrations. To test such hypotheses, patient compliance with the blood sampling should be optimized by the development of a minimally intrusive limited sampling schedule (LSS) to characterize F-ara-A pharmacokinetics. To this end, we sought to create the first F-ara-A population pharmacokinetic model and subsequently a LSS. EXPERIMENTAL DESIGN: A retrospective evaluation of F-ara-A pharmacokinetics was conducted after one or more doses of daily i.v. fludarabine in 42 adult HCT recipients. NONMEM software was used to estimate the population pharmacokinetic parameters and compute the area under the concentration-time curve. RESULTS: A two-compartment model best fits the data. A LSS was constructed using a simulation approach, seeking to minimize the scaled mean squared error for the area under the concentration-time curve for each simulated individual. The LSS times chosen were 0.583, 1.5, 6.5, and 24 hours after the start of the 30-minute fludarabine infusion. DISCUSSION: The pharmacokinetics of F-ara-A in an individual HCT patient can be accurately estimated by obtaining four blood samples (using the LSS) and maximum a posteriori Bayesian estimation. CONCLUSION: These are essential tools for prospective pharmacodynamic studies seeking to determine if clinical outcomes are related to F-ara-A pharmacokinetics in patients receiving i.v. fludarabine in the ambulatory clinic.

Simultaneous sustained release of fludarabine monophosphate and Gd-DTPA from an interstitial liposome depot in rats: potential for indirect monitoring of drug release by magnetic resonance imaging.

INTRODUCTION: Cytostatic depot preparations are interstitially administered for local chemotherapy and prevention of tumor recurrence. It would be of interest to monitor in patients as to when, to what extent, and exactly where, the drug is actually released. Liposomes containing a hydrophilic cytostatic and a hydrophilic contrast agent might be expected to release both agents simultaneously. If so, then drug release could be indirectly followed by monitoring contrast enhancement at the injection site. METHODS: Multivesicular liposomes containing the antimetabolite fludarabine monophosphate and the magnetic resonance imaging (MRI) contrast agent Gd-DTPA were subcutaneously injected in rats and both agents were monitored at the injection site for 6 weeks by 19F nuclear magnetic resonance spectroscopy (MRS) in vivo and contrast-enhanced 1H MRI (T1w 3D FLASH), respectively, in a 1.5-T whole-body tomograph. The MRS and MRI data were analyzed simultaneously by pharmacokinetic modeling using NONMEM. RESULTS: During an initial lag time, the amount of drug at the injection site stayed constant while the contrast-enhanced depot volume expanded beyond the volume injected. Drug amount and depot volume then decreased in parallel. Lag time and elimination half-life were 9 and 6 days, respectively, in three animals, and were about 50% shorter in another animal where the depot split into sub-depots. CONCLUSION: The preliminary data in rats suggest that simultaneous release of a hydrophilic cytostatic and a hydrophilic contrast agent from an interstitial depot can be achieved by encapsulation in liposomes. Thus, there seems to be a potential for indirect drug monitoring through imaging.

Fludarabine phosphate and melphalan: a reduced intensity conditioning regimen suitable for allogeneic transplantation that maintains the graft versus malignancy effect.

Reduced intensity conditioning (RIC) for allogeneic stem cell transplantation allows stable donor cell engraftment with the maintenance of a graft versus malignancy effect. Many different regimens exist employing various combinations of chemotherapy, radiotherapy and T-cell depletion. We examined the role of non-T-cell depleted RIC regimens in 56 patients with haematological malignancies. Patients received fludarabine phosphate for 5 days (30 mg/m2 in 35 patients, 25 mg/m2 in 21 patients) and melphalan for 1 day (140 mg/m2 in 36 patients, 100 mg/m2 in 20 patients). Immunosuppression was with CyA alone in 33 patients and CyA/MTX in 23 patients. Twenty-four of the 26 patients with chimerism data showed >95% donor chimerism at 3 months post transplant. aGVHD occurred in 18% of patients receiving CyA/MTX compared to 53% of patients receiving CyA. The 100-day mortality rate was 0.16 (95%CI 0.08-0.28) and 1-year nonrelapse mortality was 0.24 (95%CI 0.13-0.38). Thirty-three patients remained alive and in CR at a median of 19 months post transplant (range 3-38 months). We have shown that patients transplanted with fludarabine phosphate, melphalan 100 mg/m2 and with CyA/MTX as post transplant immunosuppression can achieve good disease control with an acceptable level of toxicity. Further studies are required to confirm these findings.

Fludarabine phosphate-CVP in patients over 60 years of age with advanced, low-grade and follicular lymphoma: a dose-finding study.

The aim of this study was to establish a safe and effective regimen of fludarabine phosphate, cyclophosphamide, vincristine and prednisone (F-CVP) as first-line treatment for elderly patients with advanced, low-grade non-Hodgkin's lymphoma. Twenty-three patients >60 years were assigned successively to eight treatment cycles (Dose level 1: low F, low CV [n=4]; 2A: high F, low CV [n=8]; 2B: low F, high CV [n=4]; 3: high F, high CV [n=7]). High and low levels were: F, 25 and 20mg/m(2), respectively (Days 1-5); C, 750 and 500 mg/m(2), respectively (Day 1); and V, 1.4 and 1mg/m(2), respectively (Day 1). Patients received P at 40 mg/m(2) on Days 1-5. Response was assessed after Cycles 2, 4, 6 and 8. At level 3, dose-limiting toxicity (opportunistic infections and neutropenia) became evident, particularly after Cycle 6. Further patients were recruited at Dose level 2A. All regimens proved effective, with an OR rate of 78% (65% CR), and 3-year survival of 65% (+/-10%). Among 18 responders, 51% were still in response at 3 and 5 years. The study shows that this combination therapy is highly effective. The addition of F to CVP at Dose level 2A was feasible and increased the CR rate, with good tolerability in elderly patients.

The histone deacetylase inhibitor MS-275 interacts synergistically with fludarabine to induce apoptosis in human leukemia cells.

Interactions between the novel benzamide histone deacetylase (HDAC) inhibitor MS-275 and fludarabine were examined in lymphoid and myeloid human leukemia cells in relation to mitochondrial injury, signal transduction events, and apoptosis. Prior exposure of Jurkat lymphoblastic leukemia cells to a marginally toxic concentration of MS-275 (e.g., 500 nM) for 24 h sharply increased mitochondrial injury, caspase activation, and apoptosis in response to a minimally toxic concentration of fludarabine (500 nM), resulting in highly synergistic antileukemic interactions and loss of clonogenic survival. Simultaneous exposure to MS-275 and fludarabine also led to synergistic effects, but these were not as pronounced as observed with sequential treatment. Similar interactions were noted in the case of (a) other human leukemia cell lines (e.g., U937, CCRF-CEM); (b) other HDAC inhibitors (e.g., sodium butyrate); and (c) other nucleoside analogues (e.g., 1-beta-D-arabinofuranosylcytosine, gemcitabine). Potentiation of fludarabine lethality by MS-275 was associated with acetylation of histones H3 and H4, down-regulation of the antiapoptotic proteins XIAP and Mcl-1, enhanced cytosolic release of proapoptotic mitochondrial proteins (e.g., cytochrome c, Smac/DIABLO, and apoptosis-inducing factor), and caspase activation. It was also accompanied by the caspase-dependent down-regulation of p27(KIP1), cyclins A, E, and D(1), and cleavage and diminished phosphorylation of retinoblastoma protein. However, increased lethality of the combination was not associated with enhanced fludarabine triphosphate formation or DNA incorporation and occurred despite a slight reduction in the S-phase fraction. Prior exposure to MS-275 attenuated fludarabine-mediated activation of MEK1/2, extracellular signal-regulated kinase, and Akt, and enhanced c-Jun NH(2)-terminal kinase phosphorylation; furthermore, inducible expression of constitutively active MEK1/2 or Akt significantly diminished MS-275/fludarabine-induced lethality. Combined exposure of cells to MS-275 and fludarabine was associated with a significant increase in generation of reactive oxygen species; moreover, both the increase in reactive oxygen species and apoptosis were largely attenuated by coadministration of the free radical scavenger L-N-acetylcysteine. Finally, prior administration of MS-275 markedly potentiated fludarabine-mediated generation of the proapoptotic lipid second messenger ceramide. Taken together, these findings indicate that the HDAC inhibitor MS-275 induces multiple perturbations in signal transduction, survival, and cell cycle regulatory pathways that lower the threshold for fludarabine-mediated mitochondrial injury and apoptosis in human leukemia cells. They also provide insights into possible mechanisms by which novel, clinically relevant HDAC inhibitors might be used to enhance the antileukemic activity of established nucleoside analogues such as fludarabine.

Successful treatment of mu-heavy chain disease with fludarabine monophosphate: a case report.

Heavy chain diseases (HCD) are monoclonal lymphoproliferative disorders of B-cells characterized by the synthesis of truncated heavy chains without associated light chains. In patients with mu-HCD, which is a very rare form of HCD, neoplastic cells produce immunoglobulin M heavy chain. The prognosis for patients with mu-HCD is poor, and there is no specific treatment for mu-HCD. In this report, we present a patient with mu-HCD accompanied by splenomegaly and thrombocytopenia. We treated this patient with the fludarabine monophosphate therapy we use for patients with B-cell chronic lymphocytic leukemia. After 5 courses of fludarabine monophosphate treatment, the splenomegaly and thrombocytopenia improved. Fludarabine monophosphate therapy may be a new strategy to improve the prognosis of patients with mu-HCD.