Pharmacokinetic study of single doses of oral fludarabine phosphate in patients with "low-grade" non-Hodgkin's lymphoma and B-cell chronic lymphocytic leukemia

Targeted ablation of signal transducer and activator of transduction 1 alleviates inflammation by microglia/macrophages and promotes long-term recovery after ischemic stroke

BACKGROUND

Brain microglia and macrophages (Mi/MΦ) can shift to a harmful or advantageous phenotype following an ischemic stroke. Identification of key molecules that regulate the transformation of resting Mi/MΦ could aid in the development of innovative therapies for ischemic stroke. The transcription factor signal transducer and activator of transduction 1 (STAT1) has been found to contribute to acute neuronal death (in the first 24 h) following ischemic stroke, but its effects on Mi/MΦ and influence on long-term stroke outcomes have yet to be determined.

METHODS

We generated mice with tamoxifen-induced, Mi/MΦ-specific knockout (mKO) of STAT1 driven by Cx3cr1^CreER. Expression of STAT1 was examined in the brain by flow cytometry and RNA sequencing after ischemic stroke induced by transient middle cerebral artery occlusion (MCAO). The impact of STAT1 mKO on neuronal cell death, Mi/MΦ phenotype, and brain inflammation profiles were examined 3-5 days after MCAO. Neurological deficits and the integrity of gray and white matter were assessed for 5 weeks after MCAO by various neurobehavioral tests and immunohistochemistry.

RESULTS

STAT1 was activated in Mi/MΦ at the subacute stage (3 days) after MCAO. Selective deletion of STAT1 in Mi/MΦ did not alter neuronal cell death or infarct size at 24 h after MCAO, but attenuated Mi/MΦ release of high mobility group box 1 and increased arginase 1-producing Mi/MΦ 3d after MCAO, suggesting boosted inflammation-resolving responses of Mi/MΦ. As a result, STAT1 mKO mice had mitigated brain inflammation at the subacute stage after MCAO and less white matter injury in the long term. Importantly, STAT1 mKO was sufficient to improve functional recovery for at least 5 weeks after MCAO in both male and female mice.

CONCLUSIONS

Mi/MΦ-targeted STAT1 KO does not provide immediate neuroprotection but augments inflammation-resolving actions of Mi/MΦ, thereby facilitating long-term functional recovery after stroke. STAT1 is, therefore, a promising therapeutic target to harness beneficial Mi/MΦ responses and improve long-term outcomes after ischemic stroke.

Efficacy and long-term toxicity of the rituximab-fludarabine-cyclophosphamide combination therapy in Waldenstrom's macroglobulinemia

Waldenstrom's macroglobulinemia is generally treated with alkylating agents, purine analogs and monoclonal antibodies, alone or in combination. We report the outcomes of 82 patients (median age 61 years) treated with the RFC combination. Twenty-five patients were treatment-naive. RFC was administered every 4 weeks, for a median of five cycles. At treatment discontinuation, the overall response rate was 85.4%. The responses improved after treatment discontinuation in 25 patients, with a median time to best response achievement of 10.8 months, raising the major response rate (PR, VGPR and CR) from 64.6% to 76.8%. With a median follow-up of 47 months, the median progression-free survival time had not been reached (67% PFS at 48 months) and was influenced by age and treatment status before RFC. Likewise, the median time to next therapy had not been reached. Two cases of myelodysplastic syndrome/AML and 3 cases of transformation to aggressive lymphoma occurred. Thirteen patients died. The 3-year overall survival rate was 90%. Long-lasting cytopenias occurred in 19 patients. The RFC combination thus gave a high response rate and durable responses, even in heavily treatment-experienced patients. The high incidence of long-lasting cytopenia might be reduced by giving fewer courses and thereby minimizing myelotoxicity. Am. J. Hematol. 91:782-786, 2016. © 2016 Wiley Periodicals, Inc.

Cladribine and Fludarabine Nucleotides Induce Distinct Hexamers Defining a Common Mode of Reversible RNR Inhibition

The enzyme ribonucleotide reductase (RNR) is a major target of anticancer drugs. Until recently, suicide inactivation in which synthetic substrate analogs (nucleoside diphosphates) irreversibly inactivate the RNR-α2β2 heterodimeric complex was the only clinically proven inhibition pathway. For instance, this mechanism is deployed by the multifactorial anticancer agent gemcitabine diphosphate. Recently reversible targeting of RNR-α-alone coupled with ligand-induced RNR-α-persistent hexamerization has emerged to be of clinical significance. To date, clofarabine nucleotides are the only known example of this mechanism. Herein, chemoenzymatic syntheses of the active forms of two other drugs, phosphorylated cladribine (ClA) and fludarabine (FlU), allow us to establish that reversible inhibition is common to numerous drugs in clinical use. Enzyme inhibition and fluorescence anisotropy assays show that the di- and triphosphates of the two nucleosides function as reversible (i.e., nonmechanism-based) inhibitors of RNR and interact with the catalytic (C site) and the allosteric activity (A site) sites of RNR-α, respectively. Gel filtration, protease digestion, and FRET assays demonstrate that inhibition is coupled with formation of conformationally diverse hexamers. Studies in 293T cells capable of selectively inducing either wild-type or oligomerization-defective mutant RNR-α overexpression delineate the central role of RNR-α oligomerization in drug activity, and highlight a potential resistance mechanism to these drugs. These data set the stage for new interventions targeting RNR oligomeric regulation.

The addition of rituximab to fludarabine and cyclophosphamide chemotherapy results in a significant improvement in overall survival in patients with newly diagnosed mantle cell lymphoma: results of a randomized UK National Cancer Research Institute trial

Mantle cell lymphoma is an incurable and generally aggressive lymphoma that is more common in elderly patients. Whilst a number of different chemotherapeutic regimens are active in this disease, there is no established gold standard therapy. Rituximab has been used widely to good effect in B-cell malignancies but there is no evidence that it improves outcomes when added to chemotherapy in this disease. We performed a randomized, open-label, multicenter study looking at the addition of rituximab to the standard chemotherapy regimen of fludarabine and cyclophosphamide in patients with newly diagnosed mantle cell lymphoma. A total of 370 patients were randomized. With a median follow up of six years, rituximab improved the median progression-free survival from 14.9 to 29.8 months (P<0.001) and overall survival from 37.0 to 44.5 months (P=0.005). This equates to absolute differences of 9.0% and 22.1% for overall and progression-free survival, respectively, at two years. Overall response rates were similar, but complete response rates were significantly higher in the rituximab arm: 52.7% vs. 39.9% (P=0.014). There was no clinically significant additional toxicity observed with the addition of rituximab. Overall, approximately 18% of patients died of non-lymphomatous causes, most commonly infections. The addition of rituximab to fludarabine and cyclophosphamide chemotherapy significantly improves outcomes in patients with mantle cell lymphoma. However, these regimens have significant late toxicity and should be used with caution. This trial has been registered (ISRCTN81133184 and clinicaltrials.gov:00641095) and is supported by the UK National Cancer Research Network.

Evaluating abbreviated induction with fludarabine, cyclophosphamide, and dose-dense rituximab in elderly patients with chronic lymphocytic leukemia

Elderly patients with chronic lymphocytic leukemia (CLL) are underrepresented in trials evaluating fludarabine, cyclophosphamide, and rituximab (FCR). We assessed four cycles of FCR with two additional rituximab doses on day 14 of cycles 1 and 2 in 194 untreated CLL patients > 65 years (median age 71.2) without del17p. Four FCR cycles were administered to 90.7% (176/194), with (n = 74) or without (n = 102) dose-delay and/or dose-reduction. A total of 50% grade 3/4 neutropenia occurred after each cycle. Only 6.2% cycles were associated with severe infection. Complete remission (CR) was achieved in 19.7%, and partial remission (PR) in 73.9% of patients. Minimal residual disease (MRD) was negative in 36.7%. Overall survival at 36 months was estimated at 87.4%. Oral FC and dose-dense rituximab is feasible and active in fit elderly CLL patients. However, myelosuppression is significant and frequent dose adaptations are required implying that these results cannot be generalized to unfit or frail elderly CLL.

Pharmacokinetic modeling of therapies for systemic lupus erythematosus

With the increasing use of different types of therapies in treating autoimmune diseases such as systemic lupus erythematosus (SLE), there is a need to utilize pharmacokinetic (PK) strategies to optimize the clinical outcome of these treatments. Various PK analysis approaches, including population PK modeling and physiologically based PK modeling, have been used to evaluate drug PK characteristics and population variability or to predict drug PK profiles in a mechanistic manner. This review outlines the PK modeling of major SLE therapies including immunosuppressants (methotrexate, azathioprine, mycophenolate and cyclophosphamide, among others) and immunomodulators (intravenous immunoglobulin). It summarizes the population PK modeling, physiologically based PK modeling and model-based individualized dosing strategies to improve the therapeutic outcomes in SLE patients.

Chemoimmunotherapy with oral low-dose fludarabine, cyclophosphamide and rituximab (old-FCR) as treatment for elderly patients with chronic lymphocytic leukaemia

Median age at diagnosis for chronic lymphocytic leukaemia (CLL) patients is now 72 years, thus a consistent number of patients may not tolerate standard doses i.v. of fludarabine, cyclophosphamide and rituximab (FCR), the best available therapy, due to unacceptable myelotoxicity and risk of severe infections. We studied safety and efficacy of the addition of rituximab to the oral low-dose FC regimen (old-FCR) in a selected population of 30 elderly (median age 75, 15 untreated, 15 treated with 1 prior therapy) CLL patients. Complete remission (CR) rate was 80% in the untreated patients (overall response rate, ORR 93%), and 30% in pretreated patients (ORR 74%). Progression free survivals (PFS) were 45 months and 30 months in the untreated and treated patients, respectively. In patients achieving CR, old-FCR led to PFS of 67 months. Moreover, haematological toxicity was mild (grade 3-4: 15%) and patients were treated mostly in outpatient clinic. Old-FCR could be a good therapy option for elderly CLL patients outside clinical trials, larger studies are needed to confirm our findings.

Ocular toxicity of fludarabine: a purine analog

The purine analogs, fludarabine and cladribine represent an important class of chemotherapy agents used to treat a broad spectrum of lymphoid malignancies. Their toxicity profiles include dose-limiting myelosuppression, immunosuppression, opportunistic infection and severe neurotoxicity. This review summarizes the neurotoxicity of high- and standard-dose fludarabine, focusing on the clinical and pathological manifestations in the eye. The mechanisms of ocular toxicity are probably multifactorial. With increasing clinical use, an awareness of the neurological and ocular vulnerability, particularly to fludarabine, is important owing to the potential for life- and sight-threatening consequences.

Older and new purine nucleoside analogs for patients with acute leukemias

Purine nucleoside analogs (PNAs) compose a class of cytotoxic drugs that have played an important role in the treatment of hematological neoplasms, especially lymphoid and myeloid malignancies. All PNA drugs have a chemical structure similar to adenosine or guanosine, and they have similar mechanisms of action. They have many intracellular targets: they act as antimetabolites, competing with natural nucleosides during DNA or RNA synthesis, and as inhibitors of key cell enzymes. In contrast to other antineoplastic drugs, PNAs act cytotoxically, both in the mitotic and quiescent cell cycle phases. In the last few years, three PNAs have been approved for the treatment of lymphoid malignancies and other hematological disorders: 2-chlorodeoxyadenosine (2-CdA), fludarabine and pentostatin. 2-CdA and fludarabine are also active in the treatment of acute myeloid leukemia (AML). These drugs, in combination with cytarabine and other agents, are commonly used as salvage regimens in relapsed or refractory AML. Moreover, the addition of 2-CdA to the standard induction regimen is associated with an increased rate of complete remission and improved survival of adult patients with AML. More recently three novel PNAs have been synthesized and introduced into clinical trials: clofarabine, nelarabine and forodesine. Clofarabine is the most promising PNA in current clinical trials in pediatric and adult patients with acute leukemias. Nelarabine is more cytotoxic in T-lineage than in B-lineage leukemias. Clofarabine and nelarabine have been approved for the treatment of refractory patients with acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma. Clofarabine is also an active drug in AML treatment when administered either alone or in combination regimens as front-line treatment and in relapsed or refractory patients. Unlike other PNA, forodesine is not incorporated into DNA but displays a highly selective purine nucleoside phosphorylase inhibitory action. Forodesine is undergoing clinical trials for the treatment of T-cell malignancies, including T-cell ALL. This article summarizes recent achievements in the mechanism of action, pharmacological properties and clinical activity and toxicity of PNAs, as well as their emerging role in lymphoid and myeloid acute leukemias.

Omega 3 fatty acids increase the chemo-sensitivity of B-CLL-derived cell lines EHEB and MEC-2 and of B-PLL-derived cell line JVM-2 to anti-cancer drugs doxorubicin, vincristine and fludarabine

Background

B-Cell chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the United States. Clinical treatment of CLL is often limited due to drug resistance and severe therapy-induced toxicities. We hypothesized that the omega 3 (n-3) fatty acids, eicosapentaenoic acid (EPA) and/or docosahexaenoic acid (DHA), would increase the sensitivity of malignant B-lymphocytes to anti-cancer drugs doxorubicin, vincristine and/or fludarabine in vitro and that increased sensitivity is achieved by alterations in cell-cycle progression leading to growth inhibition and/or enhanced cell death. We further postulate that enhanced sensitivity is dependent on the formation of lipid peroxides and to the generation of reactive oxygen species (ROS).

Methods

In the present study, B-CLL-derived leukemic cell lines EHEB and MEC-2 and the B-Prolymphocytic leukemic-derived (PLL) cell line JVM-2 were tested for in vitro sensitivity against doxorubicin, vincristine or fludarabine in the presence or absence of vehicle, arachidonic acid (omega 6), EPA or DHA. Cell cycle analysis and Annexin-V assays were performed to determine cell cycle progression and % apoptotic cells, respectively. Assays for malondialdehyde, a measure of lipid peroxidation, and DCF fluorescence assays, a measure of intracellular ROS, were performed to determine if enhanced sensitivity of cells to the drugs by n-3 was dependent on the formation of ROS.

Results

Our results indicated that: 1) EPA and DHA differentially sensitized B-leukemic cell lines EHEB, JVM-2 and MEC-2 to doxorubicin, vincristine and fludarabine in vitro; 2) n-3 alone and with drug treatment increased cell death and induced G2/M arrest in a cell-type specific manner; 3) lipid peroxidation increased in the presence of n-3; 4) there was higher lipid peroxidation in MEC-2 cells in presence of DHA and doxorubicin than with either alone; 5) n-3 increased generation of ROS in MEC-2, and 6) the addition of vitamin-E abrogated the increase in ROS generation and chemo-sensitivity of MEC-2 to doxorubicin by DHA.

Conclusion

N-3’s are promising chemo-sensitizing agents for the treatment of CLL. Selective enhancement of chemo-sensitivity of EHEB, JVM-2 and MEC-2 to drugs by n-3 that is not dependent on increased lipid peroxidation and ROS generation indicates alternative mechanisms by which n-3 enhances chemo-sensitivity.

Phosphorylation of deoxycytidine kinase on Ser-74: impact on kinetic properties and nucleoside analog activation in cancer cells

Deoxycytidine kinase (dCK) (EC 2.7.1.74) is a key enzyme in the activation of several therapeutic nucleoside analogs (NA). Its activity can be increased in vivo by Ser-74 phosphorylation, a property that could be used for enhancing NA activation and clinical efficacy. In line with this, studies with recombinant dCK showed that mimicking Ser-74 phosphorylation by a S74E mutation increases its activity toward pyrimidine analogs. However, purine analogs had not been investigated. Here, we show that the S74E mutation increased the k(cat) for cladribine (CdA) by 8- or 3-fold, depending on whether the phosphoryl donor was ATP or UTP, for clofarabine (CAFdA) by about 2-fold with both ATP and UTP, and for fludarabine (F-Ara-A) by 2-fold, but only with UTP. However, the catalytic efficiencies (k(cat)/Km) were not, or slightly, increased. The S74E mutation also sensitized dCK to feed-back inhibition by dCTP, regardless of the phosphoryl donor. Importantly, we did not observe an increase of endogenous dCK activity toward purine analogs after in vivo-induced increase of Ser-74 phosphorylation. Accordingly, treatment of CLL cells with aphidicolin, which enhances dCK activity through Ser-74 phosphorylation, did not modify the conversion of CdA or F-Ara-A into their active triphosphate form. Nevertheless, the same treatment enhanced activation of gemcitabine (dFdC) into dFdCTP in CLL as well as in HCT-116 cells and produced synergistic cytotoxicity. We conclude that increasing phosphorylation of dCK on Ser-74 might constitute a valuable strategy to enhance the clinical efficacy of some NA, like dFdC, but not of CdA or F-Ara-A.

A comparison of the efficacy and safety of oral and intravenous fludarabine in chronic lymphocytic leukemia in the LRF CLL4 trial

BACKGROUND

An oral formulation of fludarabine was introduced for use in chronic lymphocytic leukemia in 2001 following studies demonstrating the bioequivalence of a 40 mg/m(2) oral dose with a 25 mg/m(2) intravenous dose. We assessed retrospectively the efficacy of these two routes of administration in the LRF CLL4 trial.

METHODS

A total of 777 patients were randomized from 1999-2004 to receive fludarabine, alone or with cyclophosphamide, or chlorambucil. In 2001, a protocol amendment allowed the oral formulation. There were 117 assessable patients who received fludarabine intravenously and 252 who received it orally. A total of 387 patients given chlorambucil acted as a control group.

RESULTS

Patients given oral fludarabine were less likely to receive the full dose (P = .0004) and experienced more, predominantly gastrointestinal, toxicity. Progression-free survival (PFS) and overall survival were not affected by the route of administration (PFS hazard ratio, 1.10; 95% confidence interval, 0.87-1.40), but the overall rate of response to treatment appeared to be lower with the oral formulation (P = .003). However, patients recruited since 2001 were older (P = .03) and were more likely to have TP53 deletion, and response rates after 2001 were also lower in the chlorambucil group. After excluding patients with TP53 deletion, no significant difference in outcome was attributable to the route of administration.

CONCLUSIONS

Although the LRF CLL4 data suggest no important difference in the effectiveness of oral compared with intravenous fludarabine, randomized trials are needed to reliably evaluate this comparison, particularly in combination with rituximab. Meanwhile, it is important to monitor compliance and gastrointestinal side effects with the oral route and to switch to intravenous therapy if a reduced dose is being received.

Pharmacokinetics, bioavailability and effects on electrocardiographic parameters of oral fludarabine phosphate

The pharmacokinetics, bioavailability and effects on electrocardiographic (ECG) parameters of fludarabine phosphate (2F-ara-AMP) were evaluated in adult patients with B-cell chronic lymphocytic leukemia. Patients received single doses of intravenous (IV) (25 mg/m(2), n=14) or oral (40 mg/m(2), n=42) 2F-ara-AMP. Plasma concentrations of drug and metabolites and digital 12-lead ECGs were monitored for 23 h after dosing. The dephosphorylated product fludarabine (2F-ara-A) was the principal metabolite present in the systemic circulation. Mean (+/-SD) elimination half-life did not differ significantly between IV and oral dosage groups (11.3+/-4.0 vs 9.7+/-2.0 h, p=0.053). Renal excretion was a major clearance pathway, along with transformation to a hypoxanthine metabolite 2F-ara-Hx. Estimated mean oral bioavailability of 2F-ara-A was 58%. Compared to the time-matched drug-free baseline Fridericia correction of the QT interval (QTcF), the mean QTcF change following 2F-ara-AMP did not differ from zero, and a treatment effect of >+10 and >+15 ms could be excluded following oral and IV 2F-ara-AMP, respectively. Similarly, heart rate, PR interval and QRS duration did not change following 2F-ara-AMP treatment. Thus the 25 mg/m(2) IV and 40 mg/m(2) oral doses of 2F-ara-AMP produce similar systemic exposure, and do not prolong QTcF, indicating low risk of drug induced Torsades de Pointes.

Development of fludarabine formulations in the treatment of chronic lymphocytic leukemia

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/m²/d would provide systemic drug exposure similar to the standard intravenous (IV) dose of 25 mg/m²/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.

Combination therapy with rituximab and intravenous or oral fludarabine in the first-line, systemic treatment of patients with extranodal marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue type

BACKGROUND

Currently, there are no consensus guidelines regarding the best therapeutic option for patients with extranodal marginal zone lymphomas of the mucosa-associated lymphoid tissue (MALT) type.

METHODS

Patients with systemically untreated or de novo extranodal MALT lymphoma received rituximab 375 mg/m(2) intravenously on Day 1 and fludarabine 25 mg/m(2) intravenously on Days 1 through 5 (Days 1-3 in patients aged >70 years) every 4 weeks, for 4 to 6 cycles. After the first cycle, oral fludarabine could be given orally at 40 mg/m(2) on the same schedule. After 3 cycles, a workup was done. Patients who achieved a complete remission (CR) received an additional cycle, and patients who achieved a partial remission (PR) received a total of 6 cycles.

RESULTS

Twenty-two patients were studied, including 12 patients with gastric lymphoma and 10 patients with extragastric MALT lymphoma. Six patients (27%) had stage IV disease. In total, 101 cycles were administered (median, 4 cycles per patients). After the third cycle, 13 patients (62%) achieved a CR, and 8 patients (38%) achieved a PR. Primary extragastric disease was an adverse factor to achieve CR after 3 cycles of chemotherapy (hazard ratio, 23.3; 95% confidence interval, 2.0-273.3). At the end of treatment, the overall response rate was 100%, and 90% of patients achieved a CR. The progression-free survival rate at 2 years in patients with gastric and extragastric MALT lymphoma was 100% and 89%, respectively. Toxicities were mild and mainly were hematologic.

CONCLUSIONS

Combination therapy with rituximab and fludarabine is a very active treatment with favorable safety profile as first-line systemic treatment for patients with extranodal MALT lymphoma.

Current status of older and new purine nucleoside analogues in the treatment of lymphoproliferative diseases

For the past few years more and more new cytotoxic agents active in the treatment of hematological malignancies have been synthesized and become available for either in vitro studies or clinical trials. Among them the class of antineoplastic drugs belonging to the purine nucleoside analogues group (PNAs) plays an important role. Three of them: pentostatin (DCF), cladribine (2-CdA) and fludarabine (FA) were approved by Food and Drug Administration (FDA) for the treatment of hematological malignancies. Recently three novel PNAs: clofarabine (CAFdA), nelarabine (ara-G) and forodesine (immucillin H, BCX-1777) have been synthesized and introduced into preclinical studies and clinical trials. These agents seem to be useful mainly for the treatment of human T-cell proliferative disorders and they are currently undergoing clinical trials in lymphoid malignancies. However, there are also several studies suggesting the role of these drugs in B-cell malignancies. This review will summarize current knowledge concerning the mechanism of action, pharmacologic properties, clinical activity and toxicity of PNAs accepted for use in clinical practice, as well as new agents available for clinical trials.

Fludarabine in the treatment of chronic lymphocytic leukemia: a review

Fludarabine (FAMP) is the most effective and most extensively studied purine analog in indolent B-cell malignancies. Its use is indicated for first-and second-line treatment of B-cell chronic lymphocytic leukemia (B-CLL). FAMP as a single agent has produced superior response rates and progression-free survival than standard therapy with chlorambucil and alkylator-based regimen. Efficacy of FAMP may be increased by combining this purine analog with other chemotherapeutic and non-chemotherapeutic agents. FAMP and cyclophosphamide combination (FC) has shown promising results with higher overall response and complete response rates than FAMP in monotherapy, although no difference has been detected in survival. Quality of response and eradication of minimal residual disease (MRD) have been reported to be associated with prolonged survival. Eradication of MRD has been achieved by combining FC with mitoxantrone or monoclonal antibody including alemtuzumab or rituximab or both. FAMP has been widely used in non-myeloablative conditioning regimens, often combined with a variety of other cytotoxic agents, with the aim of inducing enough immunosuppression to allow successful engraftment and to exert some pretransplant anti-tumor activity. The current paper provides an overview of use of FAMP as a single agent or as a cornerstone of different therapeutic strategies for treatment of B-CLL patients.

Bendamustine, but not fludarabine, exhibits a low stem cell toxicity in vitro

PURPOSE

We investigated the in vitro toxicity of bendamustine and fludarabine to hematopoietic progenitors and stem cells from healthy donors.

METHODS

Clonogenic agar colony assays, non-clonogenic long-term liquid cultures (LTC) and apoptosis assays were used to assess the cytotoxicity of both the agents.

RESULTS

Total colony-forming units (CFU) were more sensitive to fludarabine than to bendamustine in agar colony assays (IC(50) 0.7 microM/L and 8.5 microM/L, respectively). Using the Bliss independence model and combining the two agents yielded additive inhibition of progenitors. Non-clonogenic assays, including LTC and an apoptosis assay detecting activated caspases showed that stem cells are characterized by low sensitivity to bendamustine. In contrast, fludarabine strongly inhibited the viability and growth of stem cells in LTC.

CONCLUSIONS

Our data show that bendamustine is characterized by lower in vitro toxicity to hematopoietic progenitors and stem cells than fludarabine and might thus be preferable in regimens prior to stem cells apheresis.

Oral fludarabine and cyclophosphamide as front-line chemotherapy in patients with chronic lymphocytic leukemia. The impact of biological parameters in the response duration

We tested the efficacy and safety of oral fludarabine and cyclophosphamide as front-line therapy in chronic lymphocytic leukemia (CLL) and assessed the influence of immunoglobulin variable region heavy chain (IgVH) gene mutation status, interphase cytogenetic abnormalities, and expression of ZAP-70 and CD38 on clinical outcome. Thirty-seven patients with previously untreated CLL received oral fludarabine (30 mg m(2)) and oral cyclophosphamide (250 mg m(2)) for three consecutive days every 4 weeks for six cycles. Eighteen patients had unmutated and 15 had mutated IgVH genes. Nine patients had the 'high risk' cytogenetic abnormality del(11q22.3) or del(17p13.1). Fifteen patients were ZAP-70-positive and eight patients were CD38-positive. Among the 35 valuable patients, 14 patients (40%) obtained a complete response and 13 (37%) a partial response. The median progression-free survival (PFS) was 23 months and median time to re-treatment (TTR) was 38 months. A significantly lower overall response rate (43% vs. 85%, p = 0.011), a shorter PFS (22 vs. 27 months, p = 0.015), and a shorter TTR (22 vs. 40 months, p = 0.031) were noticed in the 'high risk' cytogenetic abnormalities group; TTR was also shorter in IgVH-unmutated than in IgVH-mutated patients (26 vs. 41 months, p = 0.035). Hematologic toxicity included grade IV neutropenia (ten patients) and grade III/IV anemia (three patients). Gastrointestinal toxicity was mild and no patient required hospitalization. The oral combination of fludarabine and cyclophosphamide is an effective, safe, and well-tolerated regimen that, if confirmed with larger series, will be appropriate especially in patients with low risk biological parameters.

Liposomal Coencapsulated Fludarabine and Mitoxantrone for Lymphoproliferative Disorder Treatment**Xiaobin Zhao and Jianmei Wu contributed equally to this study

Fludarabine (FLU)-based combination therapies are commonly used to treat low-grade lymphoma and chronic lymphocytic leukemia (CLL) patients. In vitro and clinical studies have indicated advantages when FLU and mitoxantrone (MTO) are applied in combination. To further enhance this effect, these two agents were coencapsulated in liposomes. FLU was passively encapsulated during liposome formation, and MTO was loaded with a transmembrane pH gradient. Entrapment efficiency, particle size, stability, and drug release kinetics were characterized. In vitro cytotoxicity study was carried out in two representative B-cell lines: Wac3CD5 and Raji. Synergism as measured by combination index (CI) was observed in cells treated with liposomes coencapsulating FLU and MTO. Annexin V/propidium iodide (PI) analysis further confirmed that coencapsulated FLU and MTO improved the percentage of apoptosis among primary CLL cells. These data suggest that adopting liposomes containing coencapsulated drug combinations constitutes a potential strategy to promote drug synergism and may have utility in the treatment of leukemia and lymphoma.

F-ara-A pharmacokinetics during reduced-intensity conditioning therapy with fludarabine and busulfan

Fludarabine is commonly used in combination with busulfan as part of conditioning regimens before allogeneic stem cell transplantation. So far, no data are available on busulfan-fludarabine drug interactions in transplant recipients. The pharmacokinetic (PK) properties of F-ara-A (9-beta-D-arabinosyl-2-fluoradenine) before and after application of busulfan were prospectively investigated in 16 patients with hematological malignancies. The conditioning regimen consisted of intravenous fludarabine 30 mg/m(2) over 30 min from day -6 to day -3, and oral busulfan given at 1 mg/kg every 6 h from day -5 to day -2. PK parameters of F-ara-A, derived from plasma and urine on day -6, -5, -4 and -3, were determined using high-performance liquid chromatography (HPLC). AUC, C(max), t(1/2), Cl(total) and V(SS) were 21.9 microMh, 3.5 microM, 13.0 h, 4.3 l/h/m(2), 60.0 l/m(2) on day -6 and 22.4 microMh, 3.5 microM, 14.0 h, 4.7 l/h/m(2), 69.0 l/m(2) on day -5 to (-2), respectively. Cl(renal) and the urine-recovery were 4.8 l/h, 43.7% of the fludarabine dose on day -6 and 3.9 l/h, 44.2% of the fludarabine dose on day -5 to (-2), respectively. There were no changes in PK parameters of fludarabine given before and after intake of busulfan. This implies that a clinically relevant busulfan-fludarabine drug interaction is unlikely.

Fludarabine

Fludarabine (Fludara), a purine nucleoside analogue, has been extensively evaluated in the treatment of a number of lymphoproliferative malignancies, including various types of non-Hodgkin's lymphoma. Clinical studies have shown that fludarabine (alone, and particularly as a component of combination therapy) can result in high overall and complete response in adults with various types of non-Hodgkin's lymphoma, including follicular lymphoma. As mono- or combination therapy, intravenous fludarabine is as effective as several other standard treatment regimens in treatment-naive patients and is also effective in patients with recurrent or refractory disease. The efficacy of fludarabine therapy is improved with the use of rituximab, as part of the initial therapeutic regimen or as maintenance therapy, and deserves consideration. The once-daily oral formulation was effective in the treatment of patients with relapsed indolent B-cell non-Hodgkin's lymphoma; however, further studies are required to confirm its role and establish its efficacy relative to that of standard treatment in this patient population. Fludarabine has generally acceptable tolerability; however, it is associated with haematological adverse events, including myelosuppression. Fludarabine, therefore, provides a highly effective first- or second-line option in the treatment of non-Hodgkin's lymphoma.

In vitro screening for synergism of high-linear energy transfer 213Bi-radiotherapy with other therapeutic agents for the treatment of B-cell chronic lymphocytic leukemia

BACKGROUND

External beam radiotherapy and beta-radioimmunotherapy (RIT) are effective treatments for lymphoid malignancies. The development of RIT with alpha-emitters is attractive, owing to the high (LET) nature and short path length of alpha particles allowing for higher tumor cell kill and lower toxicity to healthy tissues.

OBJECTIVES

The aim of this study was to assess the response of B-Cell chronic lymphocytic leukemia (B-CLL) cells in vitro after treatment with chemotherapy (cisplatin, fludarabine, doxorubicin, or vincristine) or other pharmaceuticals (colchicine, simvastatin, or cyclosporin A) in combination with (60)Co-gamma or (213)Bi-alpha-irradiation.

METHODS

(213)Bi was eluted from a (225)Ac generator. Apoptosis was scored by flow cytometric analysis of the cells stained with Annexin-V and 7 amino actinomycin D. Metabolic activity was assessed by a MTT assay.

RESULTS

The response induced by alpha- irradiation is systematically higher than the response induced by gamma-irradiation. The combination of drug treatment with alpha-irradiation induced a systematic, higher response, compared to treatment with drugs alone, even for the highest concentrations used. For all the drugs used in this study, synergism or additivity was demonstrated for the combination of drugs and radiotherapy with a stronger effect for alpha-particles.

CONCLUSIONS

The results of this in vitro study highlight a potential benefit of alpha-irradiation in combination with the drugs considered in this study.

Role of fludarabine in hematological malignancies

Fludarabine is a prodrug that is converted to the free nucleoside 9-beta-D-arabinosyl-2-fluoroadenine (F-ara-A), which enters cells and accumulates mainly as the 5'-triphosphate, F-ara-ATP. F-ara-ATP has multiple mechanisms of action, which are mostly directed toward DNA. Collectively, these actions affect DNA synthesis, which is the major mechanism of F-ara-A-induced cytotoxicity. Secondarily, incorporation into RNA and inhibition of transcription has been shown in cell lines. As a single agent, fludarabine has been effective for indolent leukemia. Biochemical modulation strategies resulted in enhanced accumulation of cytarabine triphosphate and led to the use of fludarabine for the treatment of acute leukemia. The combination of fludarabine with DNA-damaging agents to inhibit DNA repair processes has been highly effective for indolent leukemia and lymphomas. Other strategies have incorporated fludarabine into preparative regimens for nonmyeloablative stem-cell transplantation.

Fludarabine in chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia in the Western world. Historically, CLL patients have received prednisone- or chlorambucil-containing regimens, resulting in modest responses and a slim chance of long-term survival. The addition of purine nucleoside analogues, specifically fludarabine, to the armamentarium has significantly improved efficacy in treatment-naive or heavily pretreated CLL patients. Since the 1980s, fludarabine monotherapy has demonstrated an improvement in response over historical chemotherapeutic agents. Single-agent fludarabine therapy has expanded into a combination regimen containing cyclophosphamide and has further evolved to incorporate monoclonal antibodies. A review of the fludarabine literature shows that these advancements in fludarabine-containing therapy have enhanced the overall patient response with a potential increase in survival time, thus representing progress towards a superior treatment for CLL.

Phase II study of oral fludarabine phosphate in relapsed indolent B-Cell non-Hodgkin's lymphoma

PURPOSE

Although intravenous (IV) fludarabine phosphate is effective against indolent B-cell non-Hodgkin's lymphoma (B-NHL), IV administration for 3 to 5 consecutive days is inconvenient in an outpatient setting. To assess the efficacy and toxicity of oral fludarabine phosphate in patients with indolent B-NHL, we conducted a multicenter phase II study.

PATIENTS AND METHODS

Patients with relapsed indolent B-NHL received fludarabine phosphate tablets orally once daily on days 1 through 5 every 28 days for three to six cycles. The efficacy was separately analyzed in a mantle-cell lymphoma (MCL) cohort and indolent B-NHL except for MCL (IL) cohort. The primary end point was the overall response rate (ORR).

RESULTS

Fifty-two patients, including 46 in the IL cohort (41 with follicular lymphoma) and six in the MCL cohort, were registered, and all patients were eligible. Forty-one patients (79%) had received rituximab as prior therapy. In the IL cohort, the ORR and complete response rate were 65% (30 of 46 patients; 95% CI, 50% to 79%) and 30% (14 of 46 patients; 95% CI, 18% to 46%), respectively. One of six patients with MCL achieved a partial response. The median times to treatment failure for the 46 patients in the IL cohort and for the six patients in the MCL cohort were 8.6 and 6.1 months, respectively. Hematologic toxicities, including grade 4 neutropenia (37%), were the most frequent toxicities, and nonhematologic toxicities were mild.

CONCLUSION

Oral fludarabine phosphate is highly effective in patients with relapsed indolent B-NHL who have mostly been pretreated with rituximab and is more convenient than the IV formulation.

Phase I and pharmacokinetic study of oral fludarabine phosphate in relapsed indolent B-cell non-Hodgkin's lymphoma

BACKGROUND

The primary objective of this study was to investigate the tolerability, efficacy and pharmacokinetic profile of oral fludarabine phosphate in relapsed patients with indolent B-cell non-Hodgkin's lymphoma (B-NHL).

PATIENTS AND METHODS

Patients received fludarabine phosphate orally for 5 days, for a total of one to three cycles. Tolerability was assessed using the National Cancer Institute Common Toxicity Criteria. Efficacy was assessed using the International Workshop Criteria for NHL. Pharmacokinetic samples were taken on day 1 and day 5 of the first treatment cycle.

RESULTS

Twelve patients were enrolled. One patient at 40 mg/m2/day developed grade 4 hyperuricemia. At 50 mg/m2/day, one patient developed grade 3 febrile neutropenia and grade 4 leukopenia, and another patient showed lasting grade 4 neutropenia. Most common toxicities included grade 3 or 4 lymphopenia (83%), leukopenia (50%) and neutropenia (50%). All the toxicities were reversible. The overall response rate was 67%. The AUC0-24h values on day 5 indicated a dose-dependent increase in systemically available 2-fluoro-arabinofuranosyl-adenine (2F-ara-A).

CONCLUSIONS

Oral fludarabine phosphate is safe and effective for relapsed patients with indolent B-NHL. The dose of 40 mg/m2/day is recommended for a following pivotal phase II study.

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.

Therapy of Chronic Lymphocytic Leukaemia with Purine Nucleoside Analogues

Chronic lymphocytic leukaemia (CLL) is a neoplastic disease of unknown aetiology characterised by an absolute lymphocytosis in peripheral blood and bone marrow. The disease is diagnosed most commonly in the elderly with the median age at diagnosis being about 65 years. The purine nucleoside analogues (PNAs) fludarabine, cladribine (2-chlorodeoxyadenosine) and pentostatin (2'-deoxycoformycin) are highly active in CLL, both in previously treated and in refractory or relapsed patients. These three agents share similar chemical structures and mechanisms of action such as induction of apoptosis. However, they also exhibit significant differences, especially in their interactions with enzymes involved in adenosine and deoxyadenosine metabolism. Recent randomised studies suggest that fludarabine and cladribine have similar activity in CLL. However, clinical observations indicate the existence of cross-resistance between fludarabine and cladribine. Patients who received PNAs as their initial therapy and achieved long-lasting response can be successfully retreated with the same agent. PNAs administered in combination with other chemotherapeutic agents and/or monoclonal antibodies may produce higher response rates, including complete response (CR) or molecular CR, compared with PNAs alone or other treatment regimens. Management decisions are more difficult in elderly patients because of the apparent increase in toxicity of PNAs in this population. In elderly patients, we recommend chlorambucil as the first-line treatment, with PNAs in lower doses in refractory or relapsed patients. Myelosuppression and infections, including opportunistic varieties, are the most frequent adverse effects in patients with CLL treated with PNAs. Therefore, some investigators recommend routine antibacterial and antiviral prophylaxis during and after PNA treatment. This review presents current results and treatment strategies with the use of PNAs in CLL, especially in elderly patients.

Efficacy and safety of oral fludarabine phosphate in previously untreated patients with chronic lymphocytic leukemia

PURPOSE

A prospective, multicenter, open-label, phase II clinical trial to assess oral fludarabine phosphate treatment in terms of safety, efficacy, and quality of life. Reference to a historical group of patients treated with the intravenous (IV) formulation allowed the two formulations to be compared.

PATIENTS AND METHODS

Patients with previously untreated B-cell chronic lymphocytic leukemia received 10-mg tablets of fludarabine phosphate to a dose of 40 mg/m(2)/d for 5 days, repeated every 4 weeks, for a total of six to eight cycles. Efficacy was assessed using International Workshop on Chronic Lymphocytic Leukemia and National Cancer Institute criteria for response. Safety monitoring included WHO toxicity grading for adverse events. Quality of life was also assessed.

RESULTS

Eighty-one patients received treatment. According to International Workshop on Chronic Lymphocytic Leukemia criteria, the overall response rate was 71.6% (complete remission, 37.0%; partial remission, 34.6%). The response rate using National Cancer Institute criteria was 80.2% (complete remission, 12.3%; partial remission, 67.9%). Median time to progression was 841 days (range, 28 to 1,146 days). The most frequently reported grade 3/4 toxicity was myelosuppression. WHO grade 3/4 hematological toxicities included granulocytopenia (32.1%), anemia (9.9%), and thrombocytopenia (4.9%). Gastrointestinal toxicity was more common with the oral formulation than with IV fludarabine phosphate, but was generally mild to moderate and did not require treatment. Statistically significant improvements in mean emotional and insomnia quality-of-life scores were seen after treatment.

CONCLUSION

This study demonstrates that oral fludarabine phosphate is clinically effective and generally well tolerated by patients with previously untreated B-cell chronic lymphocytic leukemia. Oral fludarabine phosphate has a similar clinical efficacy and safety profile to the IV formulation. Oral fludarabine phosphate does not adversely affect quality of life and may improve emotional and insomnia scores.

Oral fludarabine has significant activity in patients with previously untreated chronic lymphocytic leukemia, and leads to increased STAT1 levels in vivo

Fifteen patients with previously untreated chronic lymphocytic leukemia (CLL) were treated with oral fludarabine. Toxicities were mainly hematologic, and the response rate was 80%. To assess the effect of fludarabine on the transcription factor STAT1, blood samples obtained on study entry were treated in vitro with fludarabine for 24 h, and the majority of samples displayed an expected decrease in STAT1. To determine whether similar changes occurred in vivo, we developed a flow cytometric assay to quantitate STAT1 levels. On completion of fludarabine cycle 1, CLL cells showed increased STAT1 in the majority of patients, in contrast to the in vitro findings. This may reflect a survival advantage for cells that express high levels of STAT1. In conclusion, oral fludarabine is highly active and merits further investigation in previously untreated patients with CLL. Larger studies are indicated to determine optimal timing of STAT1 assessment, and if changes in STAT1 represent an in vivo indicator of response to purine analog therapy.

Oral fludarabine

Fludarabine is an antimetabolite antineoplastic agent used in the treatment of various haematological malignancies, particularly B-cell chronic lymphocytic leukaemia (CLL). An oral formulation of fludarabine has recently become available in the majority of European countries for the treatment of patients with relapsed or refractory B-cell CLL after initial treatment with an alkylating agent-based regimen. It is the first oral formulation of a purine analogue available for clinical use in B-cell CLL. Pharmacokinetic studies evaluating the bioavailability of oral fludarabine indicate that an oral dose of 40 mg/m2/day would provide similar systemic drug exposure to the standard intravenous dose of 25 mg/m2/day. A phase II study evaluated the clinical efficacy of six to eight cycles of oral fludarabine 40 mg/m2/day for 5 days of each 28-day cycle in 78 patients with previously treated B-cell CLL. Depending on the criteria used, the overall response rate was 46.2% (20.5% complete response [CR], 25.6% partial response [PR]) or 51.3% (17.9% CR, 33.3% PR). These results were similar to the 48% overall response rate reported in a similar historical control group treated with intravenous fludarabine. Myelosuppression (WHO grade 3 or 4) was the most frequently reported adverse effect with oral fludarabine therapy. Other common adverse effects included infection and gastrointestinal disturbances, although these were usually of mild to moderate severity (WHO grade 1 or 2). Overall, the tolerability profile of oral fludarabine is similar to that of the intravenous formulation.

Fludarabine in combination with cyclophosphamide decreases incidence of GVHD and maintains effective graft-versus-leukemia effect after allogeneic stem cell transplantation in murine lymphocytic leukemia

Graft-versus-host disease (GVHD) is a severe disorder and despite therapeutic efforts to decrease its distressing clinical manifestations, treatment is still not optimal. Here we report the results of studies, in which the purine analogue, fludarabine phosphate, was used in an attempt to modify and decrease GVHD after stem cell transplantation, across major histocompatibility barriers for murine leukemia. B-cell leukemia (BCL-1) bearing (BALB/c x C57BL/6) F1 mice received two cycles of fludarabine (0.8 mg/kg) for 5 days every 2 weeks, followed by 400 mg/kg cyclophosphamide i.p. Animals were then transplanted with C57BL/6 precursor cells and the development of leukemia and extent of GVHD was monitored both clinically and histopathologically. In the fludarabine-treated group, only nine of 28 (32%) mice developed leukemia, compared to 25 of 33 (76%) of control animals (P=0.0006 ). Mice treated with fludarabine-containing regimens prior to transplantation also had much less GVHD both clinically and at autopsy, while graft-versus-leukemia appeared to be augmented in the same animals.

Cellular and clinical pharmacology of fludarabine

In the past decade, fludarabine has had a major impact in increasing the effectiveness of treatment of patients with indolent B-cell malignancies. This has come about in a variety of clinical circumstances, including use of fludarabine alone as well as in combinations with DNA-damaging agents or membrane-targeted antibodies. Other strategies have used fludarabine to reduce immunological function, thus facilitating non-myeloablative stem cell transplants. Fludarabine is a prodrug that is converted to the free nucleoside 9-beta-D-arabinosyl-2-fluoroadenine (F-ara-A) which enters cells and accumulates mainly as the 5'-triphosphate, F-ara-ATP. The rate-limiting step in the formation of triphosphate is conversion of F-ara-A to its monophosphate, which is catalyzed by deoxycytidine kinase. Although F-ara-A is not a good substrate for this enzyme, the high specific activity of this protein results in efficient phosphorylation of F-ara-A in certain tissues. F-ara-ATP has multiple mechanisms of action, which are mostly directed toward DNA. These include inhibition of ribonucleotide reductase, incorporation into DNA resulting in repression of further DNA polymerisation, and inhibition of DNA ligase and DNA primase. Collectively these actions affect DNA synthesis, which is the major mechanism of F-ara-A-induced cytotoxicity. Secondarily, incorporation into RNA and inhibition of transcription has been shown in cell lines. With the standard dose of fludarabine (25 to 30 mg/m(2)/day given over 30 minutes for 5 days), plasma concentrations of about 3 micromol/L F-ara-A are achieved at the end of each infusion. Serial sampling of leukaemia cells from patients receiving these standard doses of fludarabine has demonstrated that the peak concentrations of F-ara-ATP are achieved 4 hours after start of fludarabine infusion. Although there is heterogeneity among individuals with respect to rate of F-ara-ATP accumulation, the peak concentrations are generally proportional to the dose of the drug. Knowledge of the plasma pharmacokinetics of its principal nucleoside metabolite F-ara-A, and the cellular pharmacology of the proximal active metabolite, F-ara-ATP, has provided some understanding of the activity of fludarabine when used as a single agent. Preclinical studies directed toward learning the mechanisms of action of this agent have formed the basis for several mechanism-based strategies for its combination and scheduling with other agents. As a single agent fludarabine has been effective for the indolent leukaemias. Biochemical modulation strategies resulted in enhanced accumulation of cytarabine triphosphate and led to the use of fludarabine for the treatment of acute leukaemias. Combination of fludarabine with DNA damaging agents to inhibit DNA repair processes has been highly effective for indolent leukaemias and lymphomas. The current review brings together knowledge of the mechanisms of fludarabine, the state of understanding of the plasma pharmacokinetics, and cellular pharmacodynamics of fludarabine nucleotides. This may be useful in the design of future therapeutic approaches.

Alkylating agents and nucleoside analogues in the treatment of B cell chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in the Western world. The natural clinical course is highly variable and chemotherapy is usually not indicated in early and stable disease. Treatment is needed in the progressive form of this leukemia. Chlorambucil, with or without steroids, has been for many years the drug of choice in the treatment of CLL. More recently, treatment approaches have included nucleoside analogues, (NA) fludarabine (FAMP) and cladribine (2-CdA, 2-chlorodeoxyadenosine), which seem to be the treatment of choice for patients failing standard therapies. Their role as first line therapy is being investigated in randomized trials and the results have recently been published. These studies have shown a higher overall response and complete remission (CR) rate and longer response duration in patients treated initially with NA than with chlorambucil or cyclophosphamide-based combination regimens. In contrast, overall survival is similar in patients treated with NA and alkylating agents. However, the randomized trials were designed as crossover studies which may influence survival. Combined use of NA with other cytotoxic drugs, cytokines, monoclonal antibodies and other agents may increase the CR and prolong survival time. However, the results of randomized trials comparing combination treatment with NA alone are not yet available. In conclusion, alkylating agents still have an important place in the routine management of the majority of CLL patients. NA should be routinely used as second line treatment and possibly as first line therapy in younger patients, who are candidates for potentially curative treatment such as stem cell transplantation and/or monoclonal antibodies.

Activity of oral fludarabine phosphate in previously treated chronic lymphocytic leukemia

PURPOSE

A prospective, multicenter, open-label phase II clinical trial was conducted to assess the efficacy and safety of oral fludarabine phosphate. Reference to an historical group of patients treated with the intravenous (IV) formulation allowed the investigators to compare the two formulations.

PATIENTS AND METHODS

Efficacy was assessed using the International Workshop on Chronic Lymphocytic Leukemia (IWCLL) and National Cancer Institute (NCI) criteria for complete remission (CR), partial remission (PR), stable disease, or disease progression. Safety monitoring included World Health Organization (WHO) toxicity grading for all adverse events.

RESULTS

Seventy-eight (96.3%) of 81 recruited patients with previously treated B-cell chronic lymphocytic leukemia (CLL) received 10-mg tablets of fludarabine phosphate to a dose of 40 mg/m(2)/d for 5 days, repeated every 4 weeks, for a total of six to eight cycles. According to IWCLL criteria, the overall remission rate was 46.2% (CR, 20.5%; PR, 25.6%). The comparative figures using NCI criteria were 51.3% (CR, 17.9%; PR, 33.3%). Overall, 30 incidents of severe adverse events were reported for 22 patients. WHO grade 3 or grade 4 hematologic toxicities included granulocytopenia (53.8%), leukocytopenia (28.2%), thrombocytopenia (25.6%), and anemia (24.4%). Gastrointestinal adverse events were more common with the oral formulation than previously reported with IV fludarabine phosphate. However, these events were generally mild to moderate.

CONCLUSION

This study demonstrates that oral fludarabine phosphate has similar clinical efficacy to the IV formulation and a safety profile that is both predictable and essentially similar to that of the IV formulation.

Fludarabine pharmacokinetics after subcutaneous and intravenous administration in patients with lupus nephritis

STUDY OBJECTIVE

To compare the pharmacokinetics of subcutaneous and intravenous fludarabine in patients with lupus nephritis.

DESIGN

Open-label, randomized, crossover trial conducted with a phase I-II trial.

SETTING

Government research hospital.

PATIENTS

Five patients with lupus nephritis.

INTERVENTION

Fludarabine 30 mg/m2/day was administered either subcutaneously or as a 0.5-hour intravenous infusion for 3 consecutive days. All patients received oral cyclophosphamide 0.5 g/m2 on the first day of each cycle.

MEASUREMENTS AND MAIN RESULTS

Plasma samples were collected before and 0.5, 1, 1.5, 2, 4, 8, and 24 hours after the first dose. Urine was collected at 6-hour intervals for 24 hours. Plasma and urine were analyzed for fluoro-arabinofuranosyladenine (F-ara-A), fludarabine's main metabolite, using high-performance liquid chromatography. Compartmental techniques were used to determine the pharmacokinetics of F-ara-A; a linear two-compartment model best described them. Comparison of the pharmacokinetics between subcutaneous and intravenous administration was done by using a Wilcoxon signed rank test. No significant differences were found between subcutaneous and intravenous administration in median (interquartile range) maximum concentrations of 0.51 (0.38-0.56) and 0.75 (0.52-0.91) mg/L, respectively, or in fitted area under the concentration-time curves from 0-24 hours of 4.65 (4.17-4.98) and 4.55 (3.5-4.94) mg x hour/L, respectively. Bioavailability of F-ara-A after subcutaneous dosing was approximately 105% of the bioavailability after intravenous administration. Differences in renal clearance and percentage of dose excreted in urine for subcutaneous and intravenous administration were nonsignificant. No injection site reactions were seen with subcutaneous dosing.

CONCLUSION

Subcutaneous and intravenous administration of fludarabine appear to have similar pharmacokinetics in patients with lupus nephritis. Subcutaneous injection may offer a convenient alternative to intravenous administration.

New drug development in non-Hodgkin lymphomas

The non-Hodgkin lymphomas (NHL) are characterized by initial responsiveness to a variety of chemotherapeutic regimens. Nevertheless, most patients progress and die from their disease. A number of new agents with unique mechanisms of action are in clinical development. Agents that are currently considered to be the most promising include those that induce apoptosis; those that interfere with cell cycling, tumor-associated angiogenesis, farnesylation of the Ras gene, and histone deacetylase; and those that inhibit the proteasome, among others. Increasing insights into the differences between tumors and among patients will lead to more individualized therapeutic strategies using agents directed at specific genetic and immunologic targets. More rapid accrual to high-quality clinical studies will facilitate dissemination of new agents to patients and lead to an increased cure rate for NHL.

Achieving Optimal Outcomes in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a disease of late middle age and older. The majority of patients are diagnosed because of a lymphocytosis of at least 5 x 10(9)/L on an incidental blood count. It needs to be distinguished from mantle cell lymphoma and splenic marginal zone lymphoma by lymphocyte markers. The immunophenotype of CLL is sparse surface immunoglobulin, CD5+, CD19+, CD23+, CD79b-, and FMC7-. The disease is staged according to the presence of lymphadenopathy and/or splenomegaly and the features of bone marrow suppression. Most patients have an early stage of disease when diagnosed and perhaps 50% will never progress. This group of patients have a normal life expectancy and do not require treatment beyond reassurance. Progression involves an increasing white cell count, enlarging lymph nodes and spleen, anaemia and thrombocytopenia. Complications of progression include autoimmune haemolytic anaemia and thrombocytopenia, immunodeficiency, and the development of a more aggressive lymphoma. A range of prognostic factors is available to predict progression, but most haematologists rely on close observation of the patient. Intermittent chlorambucil remains the first choice treatment for the majority of patients. Combination chemotherapy offers no advantage. Intravenous fludarabine is probably more effective than chlorambucil, but no trial has yet shown a survival advantage for using it first rather than as a salvage treatment in patients not responding to chlorambucil. It is at least 40 times as expensive as chlorambucil. Cladribine may be as effective as fludarabine, although it has been used less and is even more expensive. Patients who relapse after chlorambucil should be offered retreatment with the same agent and if refractory should be switched to fludarabine, which may also be offered for retreatment on relapse. For patients refractory to both drugs, a variety of options are available. High dose corticosteroids, high dose chlorambucil, CHOP (cyclophosphamide, prednisolone, vincristine and doxorubicin), anti-CD52, anti-CD20 and a range of experimental drugs which are being evaluated in clinical trials. Younger patients should be offered the chance of treatment with curative intent, preferably in the context of a clinical trial. Autologous stem cell transplantation after achieving a remission with fludarabine has relative safety and may produce molecular complete remissions. Only time will tell whether some of these patients are cured but it seems unlikely. Standard allogeneic bone marrow transplant is probably too hazardous for most patients, but non-myeloablative regimens hold out the hope of invoking a graft-versus-leukaemia effect without a high tumour-related mortality. Trials of immunotherapy are exciting options for a few patients in specialised centres.

Chronic lymphocytic leukemia

Chronic lymphocytic leukemia continues to attract much basic and clinical research interest. Despite recent advances, the disease still has no established cure. Nonetheless, significant strides have been made in our understanding of the genetics, biology, and clinical staging of this disease. This understanding may improve our ability to segregate patients into subtypes that differ in their cytogenesis, propensity toward disease progression, or response to standard or innovative forms of therapy. Finally, several promising new modalities of treatment are being evaluated in clinical trials, involving novel drugs or drug-combinations, monoclonal antibodies, stem cell transplantation, or gene therapy.

Treatment advances in non-Hodgkin's lymphoma

Non-Hodgkin's lymphomas (NHL) encompass a heterogeneous group of lymphoid malignancies with varying natural histories and prognoses. Recent classifications for NHL have defined distinct lymphoma entities based on morphology, immunophenotype, genetic features, clonal cell lineage and clinical features. These new, more precise classifications and characterizations of NHL will be essential in developing new targeted therapies. However, for this brief review, we will continue describe NHL primarily as indolent or aggressive. Treatment options for patients with indolent, but generally incurable, lymphomas include a 'watch and wait' approach, single agent alkylators, nucleoside analogues, combination chemotherapy, immunotherapy with monoclonal antibodies, radiolabelled monoclonal antibodies, or interferon (IFN). Vaccine therapy for indolent lymphomas is currently under intense investigation. For aggressive lymphomas, combination chemotherapy remains the standard of care. Major advances in the management of aggressive lymphomas include validation of the international prognostic index and clarification of the role of high-dose therapy with bone marrow or stem cell transplant in patients with relapsed aggressive lymphomas. Multiple randomised pilot trials of high dose therapy as initial therapy for aggressive lymphomas have shown conflicting results and await confirmatory studies.

Management of chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common form of adult leukaemia in Western countries. The diagnosis requires mature-appearing lymphocytes in the peripheral blood to >5 x 10(9)/L. The immunophenotype typically includes B cell antigens CD19, CD20 and CD23, low expression of surface immunoglobulin and CD5+, with other T cell antigens absent. Bone marrow biopsy, although not required for diagnosis, must show at least 30% lymphocytes. Cytogenetic abnormalities are frequent in patients with CLL, and may be associated with poor prognosis. Clinically, most patients are asymptomatic at presentation, with incidental lymphadenopathy and/or hepatosplenomegaly in the routine physical examination. Infections by opportunistic pathogens are the major cause of death. Aggressive transformation occurs in 10% of patients with CLL, most commonly prolymphocytic leukaemia (PLL) and Richter's syndrome. PLL de novo must be differentiated from PLL of an aggressive transformation. The incidences of autoimmune diseases and solid or haemopoietic secondary malignancies are increased in patients with CLL. Clinical stage is the strongest prognostic factor in CLL. There is no indication for early intervention. The current recommendation to start treatment includes disease-related symptoms, massive and/or progressive hepatosplenomegaly or lymphadenopathy, increasing bone marrow failure, autoimmune disease, and recurrent infections. Alkylating agents (e.g. chlorambucil) and nucleoside analogues (e.g. fludarabine) are the most active agents for CLL. Fludarabine induces higher response rates, but no improvement in overall survival has been observed. Fludarabine is the drug of choice for the majority of patients with CLL. Chlorambucil may be helpful for elderly patients with poor performance, and for patients who do not tolerate fludarabine. No drug combination is better than single agents. For patients refractory to initial treatment, referral to a clinical trial is the best choice. Other salvage therapy includes retreatment with the same initial agent (chlorambucil or fludarabine) if initial response was observed, or fludarabine for patients refractory to chlorambucil. Promising new approaches include cycle-active agents, nelarabine, biological therapy such as anti-CD52 monoclonal antibody, bone marrow transplantation, including the use of submyeloablative preparative regimens ('minitransplant') to induce graft-versus-leukaemia effect, and gene therapy. Prophylactic antibacterials and intravenous immunoglobulin should not be used routinely during supportive care. Epoetin may be helpful for patients who have anaemia without obvious cause. Assessment of response to therapy in CLL has been updated by the National Cancer Institute Working Group, and these guidelines are used worldwide for clinical trials.