Fludarabine in patients with advanced and/or resistant B-chronic lymphocytic leukemia

A case of bone lesion in a patient with relapsed chronic lymphocytic leukemia and review of the literature

Skeletal involvement in CLL is very rare. We present a case of ileum bone lesion during in a patient receiving 5th line of therapy. Despite radiotherapy and salvage therapies, subsequent bone lesions led to a fatal outcome. Further studies on the mechanism by which bone disease develops are currently needed.

Immune defects in patients with chronic lymphocytic leukemia

Over the past decade, the introduction of nucleoside analogs and monoclonal antibodies into the treatment of patients with chronic lymphocytic leukemia (CLL) has resulted in higher rates and longer duration of response. This is a significant step towards achieving the ultimate goal of disease-eradication and improved survival. A continuing problem, however, is the susceptibility of these patients to infections. Profound dysregulation of the host immune system in patients with CLL and its impact on the clinical course of the disease are well established. A number of investigators have sought to identify the mechanisms underlying this innate immune dysfunction, which is further exacerbated by the actions of the potent therapeutic agents. The early recognition of infections as well as prophylactic administration of appropriate antibiotics has been the mainstay of managing infections in patients with CLL. Hopefully, increasing understanding of the molecular events underlying the neoplastic change in CLL will lead to more targeted and less immunosuppressive therapeutic modalities. Furthermore, the understanding of the mechanisms of immune dysfunction in CLL is of pivotal importance in the novel immune-based therapeutic strategies currently under development.

How I treat refractory CLL

Therapy for patients with chronic lymphocytic leukemia (CLL) has greatly changed over the past few years. After years of stagnation, with treatment revolving around the use of rather ineffective drugs such as alkylators, many patients are now being treated with more effective agents such as purine analogs either alone or combined with other drugs and/or monoclonal antibodies. Treatment of patients refractory to these treatments is particularly challenging and should be decided only upon a careful evaluation of the disease, patient characteristics, and prognostic factors. Refractory disease should be clearly separated from relapsing disease. The only curative therapy for patients with CLL, including those with refractory disease, is allogeneic stem cell transplantation. However, the use of allogeneic transplantation is limited because of the advanced age of most patients and the high transplant-related mortality (TRM). Transplants with nonmyeloablative regimens may reduce TRM and allow more patients to receive transplants more safely. For patients in whom an allogeneic transplantation is not feasible or in whom it is deemed inappropriate, participation in phase 2 trials should be encouraged. Finally, to investigate mechanisms to overcome resistance to therapy in CLL and to identify patients that might gain benefit from early, intensive therapies (eg, based on biologic markers) constitute a challenge that needs active investigation.

Infections associated with purine analogs and monoclonal antibodies

Nucleoside analogs and monoclonal antibodies are commonly used to treat lymphoproliferative disorders and have become established as the treatment of choice in chronic lymphocytic leukemia, hairy cell leukemia, and follicular lymphomas, as well as a number of other malignant lymphoid neoplasms. When used in standard doses, these agents have a low incidence of extramedullary side effects resulting in their inclusion in a number of combination regimens. The most important complications associated with these drugs are myelosuppression, immunosuppression and infections. This is further accentuated when they are used in combination with other drugs such as alkylating agents. Several investigators have attempted to delineate the risk factors predicting the risk of infections associated with these agents. Furthermore, risk-based strategies to decrease the incidence of these infectious complications have been proposed.

Fludarabine, cyclophosphamide and mitoxantrone in the treatment of resistant or relapsed chronic lymphocytic leukaemia

We evaluated the efficacy and toxicity of fludarabine combined with cyclophosphamide and mitoxantrone (FCM) in patients with relapsed or resistant chronic lymphocytic leukaemia (CLL). In total, 37 patients with recurrent or resistant CLL received FCM: fludarabine 25 mg/m2 intravenously (IV), d 1-3; cyclophosphamide 200 mg/m2 IV, d 1-3; and mitoxantrone 6 mg/m2 IV, d 1, at 4-week intervals for up to six courses. Moreover, 23 patients received FCM with cyclophosphamide 600 mg/m2 i.v. and mitoxantrone 8 mg/m2 i.v. on d 1. In addition to clinical methods, response was assessed using cytofluorometric and molecular techniques. 'In vitro' sensitivity to the FCM regimen was also analysed in 20 samples. The median number of courses given was 3 (range: 1-6). Overall, 30 patients (50%) achieved complete response (CR), including 10 cases of negative minimal residual disease (MRD(-)) (17%), and 17 (28%) partial response (PR). The median duration of response was 19 months. 'In vitro' sensitivity also correlated with CR achievement (P = 0.04). Main toxicity consisted of neutropenia, infections (8% of courses), and nausea and vomiting. The treatment-related mortality was 5%. FCM did not hamper stem cell harvesting in patients who were candidates for autologous stem cell transplantation. FCM induced a high CR rate, including an important number of MRD(-), in patients with previously treated CLL.

Cytotoxic combination of loxoribine with fludarabine and mafosfamide on freshly isolated B-chronic lymphocytic leukemia cells

Fludarabine has shown a definite clinical activity in B-cell chronic lymphocytic leukemia (B-CLL). Recently it has been demonstrated that loxoribine, a guanine ribonucleotide derivative, is able to increase the cytotoxicity of fludarabine in B-CLL cells, in vitro. We have here extended these findings by testing the activity of loxoribine in combination with fludarabine and mafosfamide. As we have previously demonstrated, loxoribine enhances the activity of fludarabine at all concentrations, while only lower doses of mafosfamide seem to be positively affected by loxoribine. The combination of fludarabine and mafosfamide is synergistic on CLL cells, and the cytotoxic activity is increased by the addition of loxoribine. We have also evaluated the pro-apoptotic activity of each drug, both alone and in combination; these results are concordant with the cytotoxicity data, thus demonstrating that, even though loxoribine is more active in combination with fludarabine than with mafosfamide, the efficacy of the triple combination is higher than that obtained with any other agent alone or in double combination.

Results of a fludarabine induction and alpha-interferon maintenance protocol in pretreated patients with chronic lymphocytic leukemia and low-grade non-Hodgkin's lymphoma

The activity of fludarabine monophosphate (FLU) and alpha-interferon (alpha-IFN) in low-grade non-Hodgkin's lymphoma (LG-NHL) and B-cell chronic lymphocytic leukemia (B-CLL) has been demonstrated in several clinical trials. In a study of 137 previously treated patients, of whom 77 had B-CLL and 60 with LG-NHL, we used FLU as salvage chemotherapy. Dosages of 25 mg/m2 were given in 30-min infusions for 5 consecutive d. Treatment was repeated every 28 d depending on the patient's clinical status for a maximum of 6 cycles. Entrance to the alpha-IFN maintenance portion of the study depended on patient response to initial FLU. All patients who had obtained a complete or partial response after the FLU therapy were randomized to receive alpha-IFN or no further therapy. The alpha-IFN dose was 3x10(6) units 3 times per wk until disease progression. At 4 yr with a median follow-up of 22 months the percentage of patients with persistent response ranged between 20% and 30% among all the responders. Thirty-five (45%) B-CLL patients achieved major responses (complete/partial response), as did 29 (48%) of those with LG-NHL. Among the 64 patients who achieved a good response to initial therapy and who have entered the second part of the trial, there has been a rate of prolongation of remission in favour of maintenance alpha-IFN (p=0.02). FLU therapy is an effective drug inducing remission in pretreated B-CLL and LH-NHL patients. However, as with other therapeutic modalities, remission is rarely maintained beyond 2 yr. So far, maintenance alpha-IFN has not been shown to produce significantly longer remission after treatment with FLU in LG-NHL, and there is no trend towards prolonged remission in B-CLL patients. The role of FLU needs to be further evaluated in the management of lymphoproliferative disorders by introducing it in combination with other drugs (alpha-IFN) in the induction phase and in maintenance treatment.

Loxoribine affects fludarabine activity on freshly isolated B-chronic lymphocytic leukemia cells

Purine analogues like fludarabine have been shown to be superior to conventional therapy for B-cell chronic lymphocytic leukemia (B-CLL). In order to improve the activity of fludarabine, we tested its combination with loxoribine, a guanine ribonucleotide derivative, known to enhance the sensitivity of B-CLL cells to cytotoxic drugs. B-CLL cells from 6 patients were studied; co-incubation with loxoribine 100 microM increased the activity of fludarabine by 12% to 48%, as demonstrated by XTT colorimetric assay; while 1000 microM loxoribine exerted a protective effect. Accordingly, fludarabine-induced apoptosis was enhanced by the addition of loxoribine 1000 microM (39% increase). These results indicate that the combination of loxoribine and fludarabine could be of interest in B-CLL.

2-Chlorodeoxyadenosine in the treatment of relapsed/refractory chronic lymphoproliferative disorders

2-Chlorodeoxyadenosine (2-CdA) is a purine analog with cytotoxic activity on both resting and cycling lymphocytes which has been used as salvage therapy in advanced/resistant chronic lymphoproliferative disorders. In our study 39 patients (19 B-CLL, 5 B-PLL, 9 low-grade B-NHL, 5 CTCL and 1 high-grade T-NHL) who relapsed or became resistant after 1-4 chemotherapy regimens were treated with 2-CdA 6 mg/m2 per day by 2 h infusion for 5 d every 28 d. The overall clinical response rate, including complete remission (CR) and partial remission (PR), was 66%. Two of 19 (10%) B-CLL patients achieved a CR lasting 9 months, while 11/19 B-CLL (58%) and 4/5 B-PLL (3 B-PLL/B-CLL and 1 B-PLL) (80%) achieved a PR. Interestingly, 5 of 6 patients who had been previously treated with fludarabine obtained a clinical response (2 CR and 3 PR). One of 9 (11%) low-grade B-NHL patients achieved a CR and relapsed after 26 months, and 5/9 (55%) achieved a PR. One of 5 (20%) CTCL achieved a CR lasting 32 months, while 2/5 (40%) achieved a PR. The overall mean duration of PR was 7.4 months and no differences were observed among different groups of patients. Toxicity was acceptable, as only a transient severe hematological impairment was observed in 20% of the patients while nonhematological toxicity was not documented. Two patients died because of bacterial pneumonia, 1 of meningitis due to Listeria and 9 from progression of the disease. In conclusion, treatment with 2-CdA in heavily pretreated patients with chronic lymphoproliferative disorders is well tolerated and obtains high response rates, even in patients relapsed after treatment with fludarabine.

The COP regimen is not a feasible treatment for advanced, refractory chronic lymphocytic leukemia

The COP regimen has been widely used as a second-line treatment for advanced chronic lymphocytic leukemia (CLL). In this retrospective analysis of COP therapy 24 patients with CLL were included. All but two patients had previously been treated with alkylating agents and had become refractory to the therapy. The overall response rate to COP was 25%. Three patients had CR (12.5%), three PR (12.5%), five SD (21%), four PD (17%), and nine patients died (37.5%) during the COP treatments. The cause of death was neutropenic sepsis in all cases. The median duration of responses was 18 months. The median survival of all patients was 9.5 months. The survival of responders was 24.5 and of non-responders only 5.5 months. The COP regimen seems to have low efficacy in the treatment of refractory CLL and the toxicity of this regimen in the late disease phase appears to be unacceptable.

Fludarabine in resistant or relapsing B-cell chronic lymphocytic leukemia: the Spanish Group experience

Fludarabine produces high response rates in patients with B-cell chronic lymphocytic leukemia (CLL). Nevertheless, response to fludarabine of patients with previously treated CLL varies from 17% to 74% (0% to 38% CR). In 68 patients with heavily pretreated and advanced CLL, an overall response rate to fludarabine of 28% (4% CR) was observed. Response correlated with sensitivity of the disease to previous treatments (relapsing vs. refractory disease) (62% vs. 20%; p = 0.005) and, albeit not significantly, with the number of cycles of fludarabine (>3 vs. < or = 3) that patients could receive (36% vs. 15%; p = NS). Responding patients had a longer survival (median, not reached) than those not responding (median, 11 months) (p = 0.03). Severe toxicity was observed in some cases. It is concluded that fludarabine is a highly useful agent in CLL. However, in order to improve its effectiveness and decrease its toxicity, fludarabine should be given as soon as a lack of response to front-line therapy is observed and before the disease becomes completely resistant to therapy.

Salvage therapy with fludarabine in patients with progressive B-chronic lymphocytic leukemia

Thirty patients with B-chronic lymphocytic leukemia, aged 45-82 years, were treated with fludarabine. CLL was diagnosed 8-120 months earlier. The patients had been exposed to a median of 3 different regimens before treatment with fludarabine, and all had progressive disease when they entered the study. Among the 30 patients, 1 had a metastatic carcinoma and 7 patients with WHO performance status 3 died before the second cycle of fludarabine treatment could be given. The remaining 22 patients were considered eligible for response evaluation. The response rate was 32% with 1 complete response and 6 partial responses. However, seven patients achieved stable disease and 8 progressed. The median survival for responders was 24 months and for non-responders 9 months. Response to treatment was correlated with low tumor burden and performance status. In a total of 94 treatment courses, 17 febrile episodes were registered in 10 patients. We conclude that treatment with fludarabine can be useful in patients with progressive and refractory disease.

Key issues in the treatment of chronic lymphocytic leukaemia (CLL)

The outcome of the treatment of chronic lymphocytic leukaemia (CLL) has improved little over the past 30 years. The recent introduction of purine analogues, particularly fludarabine, may change this situation. These agents are highly effective and generally well tolerated. They raise the possibility of improved disease-free survival and allow appropriate patients to be considered for bone marrow transplantation (BMT). Randomised clinical trials are needed to establish the roles of purine analogues and other novel agents in improving the survival of CLL patients. These trials should use consistent diagnostic and assessment criteria to allow for the clinical heterogeneity of CLL.

Purine analogs in the treatment of low-grade lymphomas and chronic lymphocytic leukemias

The purine analogs fludarabine (FAMP), 2-chlorodeoxy-adenosine (2-CDA) and 2-deoxycoformycin (DCF) comprise a novel group of agents with high activity in low-grade lymphoid malignancies. Although all three agents share several mechanisms of action, such as the induction of apoptosis, and toxic effects, such as prolonged immunosuppression, their activity appears to be different in different disorders. While FAMP and possibly also 2-CDA are highly active in chronic lymphocytic leukemia and low-grade follicular lymphomas, 2-CDA and DCF are most effective in hairy cell leukemia. However, prospective comparative evaluations are in progress and their results may ultimately help to define the appropriate indications for and potential side effects of these highly promising new agents.

Chronic lymphocytic leukemia: present status

Chronic lymphocytic leukemia (CLL) is the form of leukemia which occurs most frequently in Western countries. Its etiology is unknown, and no relationship with viruses or genes has been demonstrated. Epidemiological data suggest that genetic and ambiental factors might be of some significance. Clinical features of CLL are due to the accumulation of leukemic cells in bone marrow and lymphoid organs as well as the immune disturbances that accompany the disease. The prognosis of patients with CLL varies. Treatment is usually indicated by the risk of the individual patient, which is clearly reflected by the stage of the disease. In the early stage (Binet A, Rai O) it is reasonable to defer therapy until disease progression is observed. By contrast, because their median survival is less than five years, patients with more advanced stages require therapy. For almost 50 years, no major advances in the management of CLL, which has revolved around the use of alkylating agents, have been made. In recent years, the therapeutic approach in patients with CLL has changed as a result of the introduction of combination chemotherapy regimens and, in particular, purine analogues. The latter are already the treatment of choice for patients not responding to standard therapies, and their role as front-line therapy is being investigated. Bone marrow transplants are also being increasingly used. It is to be hoped that in years to come the outcome of patients with CLL will be improved by these advances.

Fludarabine treatment in resistant Waldenstrom's macroglobulinemia

Fludarabine (FLU) is a fluorinated purine analogue with a promising antineoplastic activity in lymphoproliferative disorders. In this study, we evaluated the efficacy of FLU in 12 previously treated (primary refractory and refractory relapse) patients with Waldenstrom's macroglobulinemia. All patients were treated at a dosage of 25 mg/m2 per day for 5 consecutive days for a total of six courses. Of the 12 patients, 5 (41%) achieved partial response (PR), and the remaining 7 showed no benefit from the treatment. An increased response rate was obtained in the 4 primary refractory patients in which 2 PR were documented. Treatment was well-tolerated and there were no Fludarabine-related fatalities. With a mean follow-up of 10 months, only 1 PR patient has relapsed. Fludarabine is an interesting new salvage agent effective against recurrent/resistant Waldenstrom's macroglobulinemia and should be evaluated in further studies in untreated patients with Fludarabine in monochemotherapy or in combination with other active modalities.

Apoptosis induction with three nucleoside analogs on freshly isolated B-chronic lymphocytic leukemia cells

The cytotoxic effects and the induction of programmed cell death (apoptosis) by Fludarabine (FLU), 2-chlorodeoxyadenosine (2-CdA), and deoxycoformycin (DCF) with/without alpha-interferon (alpha-IFN) were evaluated in vitro against freshly isolated B-chronic lymphocytic leukemia (B-CLL) cells. Cytotoxicity was evaluated according to the soluble tetrazolium/formazan assay. Regarding the cytotoxicity, FLU, 2-CdA, and DCF showed a mean antitumor activity of 45% +/- 3.39 (mean +/- S.D.), 55% +/- 4.72, and 20% +/- 3.16, respectively. alpha-IFN alone showed a mean cytotoxic activity of 10% +/- 2.72. The cytotoxicity of these purine analogues in combination with alpha-IFN was 52% +/- 2.97, 75% +/- 3.41, and 26% +/- 7.09, respectively. We observed a statistically significant increase of cytotoxicity compared to controls in FLU alone (P < 0.05), 2-CdA (P < 0.05), and their combination with alpha-IFN (P < 0.05). Apoptosis was evaluated by electrophoresis gel of DNA oligonucleosomal fragments and by a cytofluorimetric method. Only FLU and 2-CdA activated the apoptosis and DCF showed a minor apoptotic pathway amount. These apoptosis data were confirmed by both gel electrophoresis of DNA and by propidium iodide cytofluorimetric method. FLU and 2-CdA show activity in B-CLL cells by direct cytotoxic action and the induction of cell death by apoptosis; in the future, it would be interesting to utilize these in vitro assays in monitoring chemosensitivity and predicting response for the clinical use.

Activity of fludarabine in refractory chronic lymphocytic leukemia and low grade non-Hodgkin's lymphoma--the Jerusalem experience

Twenty four patients with refractory chronic lymphocytic leukemia (CLL) and advanced low grade lymphoma (LGL) were treated with Fludarabine given at a dose of 25 mg/m2, intravenously daily for 5 days, every 28 days. Ten of the patients with LGL were in terminal leukemic phase. All patients had received previous chemotherapy, most with multiple regimens. Patients received a mean of 5.1 cycles (range 1-9). 4 patients--one with CLL and 3 with LGL--achieved a complete remission, while 7 LGL and 3 CLL patients had a partial response. Two patients remain in complete remission 23 and 25 months after completion of therapy. One patient underwent successful autologous bone marrow transplantation after achieving a complete remission, while two others had marrow cryopreserved during complete remission. The drug was well tolerated and toxicity was mild. In 9 of the 122 given cycles patients required hospitalization. In conclusion, Fludarabine is active in refractory patients with CLL and LGL and induces complete and partial remissions in some. It seems that Fludarabine could be used as primary therapy in these disorders in the future.