Cladribine in hairy cell leukemia

Cladribine results in prolonged complete remissions in most patients wo have HCL. Several studies have indicated that patients who are in complete remission have survivals that are comparable to those of normal age-matched controls. HCL-related mortality is distinctly uncommon. Nevertheless, it is unlikely that cladribine treatment of HCL is curative because MRD is common in the bone marrows of complete responders. Response criteria for HCL include clinical, hematologic, and morphologic criteria, but do not include flow cytometry, immunohistochemical analysis, or molecular studies. More sensitive techniques have been used by Filleul and colleagues to detect MRD. The used clonoegenic probes from the hypervariable regions of the immunoglobulin heavy-chain gene and performed polymerase chain reactions (PCRs) on bone marrow biopsy specimens, All seven patients who were in morphologic complete remission after a single cladribine infusion were PCR positive. These data indicate that cladribine induces protracted remissions but is not necessarily curative. MRD can be detected in most patients when sensitive techniques are used. Persistence of immunohistochemical MRD may predict detected MRD remains to be studied in a large number of patients. Investigators from the University of Pisa in Italy have used a combination of cladribine and rituximab to eradicate MRD in patients who have HCL. Ten patients received treatment with a standard infusion of cladribine. Two patients achieved a complete remission, 6 patients achieved a partial remission, and 2 patients failed to respond. All were PCR positive for the immunoglobulin heavy-chain (IgH) gene product at the completion of cladribine treatment. All 10 patients had achieved a complete hematologic response 2 months after the completion of ritximab therapy. The curative nature of this treatment will require long-term follow-up. Cladribine represents a major therapeutic advance in the treatment of HCL. The prognosis of patients who have HCL has improved greatly with cladribine therapy. Future strategies should address combination therapy with purine analogs and monclonal antibodies. These strategies should address eradication of MRD in an attempt to develop a potentially curative combination treatment program.     

The Epigenetics of Mantle Cell Lymphoma

Opinion statement There is no consensus treatment for newly diagnosed mantle cell lymphoma. The CHOP + rituximab and hyperCVAD + rituximab regimens are most commonly used. The former is limited by relatively lower rates of complete remission (CR) and frequent relapses. The latter is limited by toxicities, especially in older patients, and relapses that occur later than those usually seen with CHOP + rituximab. Thus, improved therapies are needed. The purine analog cladribine (2-cda) + rituximab has been studied as an alternative frontline regimen in MCL and is quite active with minimal toxicity. Cladribine has epigenetic activity in that it inhibits DNA methylation. Cladribine + rituximab should be further studied in newly diagnosed mantle cell lymphoma in combination with new agents such as inhibitors of histone deacetylation, the mTOR pathway, and the proteasome.     

Cladribine in indolent non-Hodgkin’s lymphoma

Before the advent of rationally designed targeted antineoplastic therapies, cladribine was identified as a lymphocyte-specific cytotoxic agent. Cladribine is a purine nucleoside analogue that is resistant to cellular catabolism. Through diverse mechanisms, cladribine is equally toxic to dividing and nondividing cells, making it highly active in indolent lymphoproliferative diseases. In clinical practice, cladribine is mostly used in the treatment of hairy cell leukemia and Waldenström’s macroglobulinemia. However, its remarkable activity in follicular lymphoma and other indolent non-Hodgkin’s lymphoma subtypes has not been more widely appreciated. Cladribine compares favorably to other standard treatments for these conditions. Future Phase III clinical studies should incorporate cladribine into multiagent chemotherapy programs to more fully evaluate its potential in indolent non-Hodgkin’s lymphoma.     

Cladribine in indolent non-Hodgkin's lymphoma

Before the advent of rationally designed targeted antineoplastic therapies, cladribine was identified as a lymphocyte-specific cytotoxic agent. Cladribine is a purine nucleoside analogue that is resistant to cellular catabolism. Through diverse mechanisms, cladribine is equally toxic to dividing and nondividing cells, making it highly active in indolent lymphoproliferative diseases. In clinical practice, cladribine is mostly used in the treatment of hairy cell leukemia and Waldenstr?m's macroglobulinemia. However, its remarkable activity in follicular lymphoma and other indolent non-Hodgkin's lymphoma subtypes has not been more widely appreciated. Cladribine compares favorably to other standard treatments for these conditions. Future Phase III clinical studies should incorporate cladribine into multiagent chemotherapy programs to more fully evaluate its potential in indolent non-Hodgkin's lymphoma.     

Treatment of mantle-cell lymphomas with intermittent two-hour infusion of cladribine as first-line therapy or in first relapse

Purpose: Cladribine (2-chlorodeoxyadenosine, 2-CdA) has been reported to be effective in the treatment of low-grade lymphomas. The objective of this multicenter study was to evaluate the activity of cladribine in mantle-cell lymphomas as first-line therapy or in first relapse using an intermittent two-hour infusion of cladribine.Patients and methods: A total of 47 courses, or an average of four courses per patient, were administered to 12 patients (seven untreated, five relapsed) with 5 mg/m2 cladribine given as an intermittent two-hour infusion over five consecutive days for a maximum of six cycles every four weeks.Results: Cladribine showed activity in patients with mantle-cell lymphomas, achieving a response rate of 58% (95% confidence interval (95% CI): 28%–85%). Myelosuppression was the major toxicity with 17% of grade 3 and 4 neutropenia. Thrombocytopenia was rare with only 2% of grade 3 and 4.Conclusion: These results demonstrate single-agent activity of cladribine in mantle-cell lymphomas using the intermittent two-hour infusion dosage regimen. To further improve treatment results, cladribine should be combined with other agents active in mantle-cell lymphomas.     

克拉屈滨治疗毛细胞白血病三例并文献复习

 【摘要】　目的　观察克拉屈滨治疗毛细胞白血病的疗效。方法　3例患者应用克拉屈滨10 mg维持24 h静脉滴注,共治疗3 d或5 d。结果　3例患者中,2例患者疗效均达到完全缓解,1例患者为接近完全缓解。结论　克拉屈滨治疗毛细胞白血病疗效显著,未发现明显的不良反应。     

Pharmacological basis for cladribine resistance

The inherent or acquired resistance of leukemic cells to cytostatic agents is a major clinical challenge. The purpose of this review was to elucidate and analyse the available data concerning mechanisms of resistance of cladribine with emphasis on recent advances in the characterization of activating and inactivating enzymes in the induction of resistance to cladribine. All available in vitro and clinical data on cladribine was undertaken. Cladribine, unlike many other drugs, is toxic to both dividing and indolent lymphoid malignancies. Cladribine is a prodrug and must be phosphorylated intracellularly to cladribine-monophosphate (MP) by the nuclear/cystosol enzyme deoxycytidine kinase (dCK) and the mitochondrial enzyme deoxyguanosine kinase. The cytotoxicity mainly depends on the accumulation of cladribine-triphosphates (TP) after phosphorylation of cladribine-MP by nucleoside monophosphate kinase and nucleoside diphosphate kinase. 5'-Nucleotidase (5'-NT) dephosphorylates cladribine-MP and the accumulation of cladribine-TP depends on the ratio of dCK and 5'-NT in the cells. The mechanisms underlying cladribine resistance are multifactorial, e.g. decreased nucleoside transport, decreased activity or deficiency of dCK, altered intracellular pools of competing nucleotides, altered regulation of ribonucleotide reductase and increased drug inactivation by 5'-NT. Finally, cladribine resistance may be a consequence of a defective induction of apoptosis. In spite of the fact that more than one mechanism can contribute to a cladribine resistance phenotype, a reduction in dCK activity is probably the major determinant of cladribine resistance. Insight into the mechanism of action and resistance to cladribine is crucial for its optimal use as well as for the development of newer analogues.     

Treatment of hairy cell leukemia-variant with cladribine

Hairy cell leukemia-variant (HCL-V) is an extremely rare chronic B-cell lymphoproliferative disorder clinically and morphologically distinct from classic hairy cell leukemia (HCL). HCL-V is thought to represent a hybrid between prolymphocytic leukemia and HCL, the nucleus more closely resembling a prolymphocyte and the cytoplasm a hairy cell. The clinical course of HCL-V is aggressive with short survivals. Since single courses of cladribine have profound activity in HCL, inducing durable complete responses in 91% of patients, we administered cladribine to 4 patients with HCL-V over a 7-year period. During this time interval 357 patients with classic HCL received cladribine at Scripps Clinic. Each patient received cladribine at 0.1 mg/kg per day by continuous intravenous infusion for 7 days, repeated at 28-day intervals depending on response status. The 4 patients ranged in age from 28 to 70. Two presented with B-symptoms, 1 had peripheral adenopathy, and all 4 displayed massive splenomegaly. Peripheral blood counts were notable for lymphocytosis associated with mild anemia and thrombocytopenia. Only 1 of the 4 patients had received prior treatment. Peripheral blood immunophenotypic analysis revealed monoclonal B cells with expression of CD11c in 3 patients, lack of CD25 expression in 3 patients and expression of CD103 in all but 1 patient. The number of cladribine courses administered ranged from two to five. Of these 4 patients, 1 (25%) achieved a complete response and 2 (50%) partial responses, for an overall response rate of 75%. Three patients underwent splenectomy after cladribine. Cladribine is an active agent in HCL-V albeit with a lower response rate than in classic HCL. The role of other treatment modalities, such as splenectomy, interferon-alpha, and 2'-deoxycoformycin, alone or in combination with cladribine awaits further evaluation.     

Phase I study of cladribine (2-chlorodeoxyadenosine) in lymphoid malignancies. Cladribine Study Group

Cladribine (2-chlorodeoxyadenosine;) is a purine analogue with clinical activity against hairy cell leukemia, chronic lymphocytic leukemia and indolent lymphoma. To clarify the toxicity profiles of cladribine, we conducted a phase I and pharmacological study of cladribine with a schedule of seven-day continuous intravenous infusion every 28 days up to a maximum of three cycles. We enrolled 10 previously-treated patients with various lymphoid malignancies. No dose-limiting toxicity (grade 4 hematologic and/or grade 3 or more non-hematologic) was observed in the three patients who received 0.06 mg/kg/day (Level 1). Of the seven patients who received 0.09 mg/kg/day (Level 2), one patient developed grade 4 hypoxemia and grade 4 thrombocytopenia, and another developed grade 4 neutropenia. Of the seven patients treated at Level 2, one with cutaneous T-cell lymphoma attained complete remission, and one with mantle cell lymphoma, one with chronic lymphocytic leukemia and one with adult T-cell leukemia-lymphoma attained partial remission. A pharmacokinetic analysis of the seven patients without leukemic cells showed that their area under the concentration versus time curves of plasma cladribine increased dose-dependently from 2661.3 +/- 300.4 nM x h at Level 1 (n = 3) to 3411.3 +/- 341.0 nM x h at Level 2 (n = 4) (P = 0.034). We conclude that the recommended phase II dose of cladribine (0.09 mg/kg/day as a seven-day continuous i.v. infusion) in Caucasian patients can be safely administered to Japanese patients. The encouraging results prompted us to plan subsequent phase II studies of cladribine against adult T-cell leukemia-lymphoma, hairy cell leukemia and indolent lymphoma.      

Gynecomastia in a case of hairy cell leukaemia--cladribine induced?

Gynecomastia is benign enlargement of the male breast and is commonly drug induced. Various drugs are responsible and chemotherapeutic drugs can also cause gynecomastia. Cladribine is now widely used for the treatment of hairy cell leukaemia. We present a case report of development of unilateral gynecomastia in a case of hairy cell leukaemia treated with cladribine and question whether this was induced by the chemotherapy.     

Two Cases of Cerebral Involvement in Malignant Lymphoma (CD20+) That Responded to Combination Therapy with Rituximab and Cladribine

Cerebral involvement frequently occurs in association with progression or relapse of malignant lymphoma. Chemotherapy with cyclophosphamide, doxorubicin, vincristine, and prednisolone, the standard chemotherapy for malignant lymphoma, is an ineffective treatment for cerebral involvement because these drugs cannot cross the blood-brain barrier. Therefore, various alternative strategies have been attempted. Although high-dose methotrexate combined with whole-brain radiotherapy is widely used to treat primary central nervous system lymphoma, there is no standard therapy to treat cerebral involvement in malignant lymphoma. Furthermore, high-dose methotrexate in combination with whole-brain radiotherapy is not always effective, and high rates of neurotoxicity are often observed, particularly in the elderly. To expand the therapeutic options for central nervous system involvement in recent years, systemic chemotherapies, including rituximab, high-dose methotrexate, and other agents that act during the S, G2, and M phases of the cell cycle, have been attempted. In our hospital, cladribine, a purine analogue with a cytocidal effect on resting malignant cells (G0/G1 phase of the cell cycle), has been used in combination with rituximab, which exhibits antitumor effects on nodal and extranodal lesions of relapsed and/or refractory B cell lymphomas, particularly cerebral lesions. Here, we report 2 representative cases of patients who were treated with cladribine plus rituximab and survived for 30 months (died of sepsis) and 52 months (still alive), respectively. The outcomes of these cases suggest that cladribine plus rituximab combination therapy with whole-brain radiotherapy may be very useful as salvage therapy for secondary central nervous system lymphoma and as initial therapy for primary central nervous system lymphoma.Key Words: Cladribine, Rituximab, Cerebral involvement in malignant lymphoma, Purine analogue     

Intermittent 2-Hour-Infusion of Cladribine as First-Line Therapy or in First Relapse of Progressive Advanced Low-Grade and Mantle Cell Lymphomas

Aim of this multicenter-study was to evaluate rate and duration of remissions and to examine toxicity of cladribine in low-grade lymphomas as first-line therapy or in first relapse using intermittent 2-hour-infusion of cladribine. A total of 294 courses, median of 5 courses per patient, were administered to 66 evaluable patients (53 previously untreated, 13 relapsed) with 5 mg/m² cladribine given as intermittent 2-hour-infusion over 5 consecutive days for a maximum of 6 cycles every four weeks. Entities: 26 follicle center, 20 lymphoplasmacytoid, 12 mantle cell, 6 T-cell, 2 marginal zone lymphomas. Fifty of 66 patients responded to cladribine corresponding to an overall response rate of 76% (95% confidence interval (95% CI): 64%-85%) with 38% CR (95% CI: 26%-51%) and a median time of remission duration of 23 months (range 645+). The overall survival rate at 48 months was 72%. For 49 previously untreated patients with B-cell lymphomas the overall response rate was 86% (95% CI: 73%-94%) with a high CR rate of 43% (95% CI: 29%-58%). Response rate for the group of 23 previously untreated patients with follicle center lymphomas was high with 96% overall response (95% CI: 78%-100%) and 57% CR rate (95% CI: 34%-77%). Cladribine also showed activity in patients with mantle cell lymphomas achieving a response rate of 58% (95% CI: 28%-85%). Myelosuppression was the major toxicity with 17% neutropenia grade 3 and 4. Thrombocytopenia was rare with only 2% grade 3 and 4. A prolonged CD4-lymphocy-topenia was observed in all patients. Life threatening complications were not observed. These results confirm the major single-agent activity of cladribine in a large cohort of patients with untreated low-grade lymphomas using the intermittent 2-hour-infusion dosage-regimen. To improve treatment results furthermore, cladribine should be combined with other agents active in low-grade lymphomas.     

Hairy cell leukemia: clinical, pathological and ultrastructural findings in Asian-Indians

Background: Hairy-cell leukemia (HCL), lymphoproliferative disease of older age, is characterized by projections from surface of abnormal cells. Aim: The aim was to study the clinical presentation and ultrastructural changes in hairy cells (HCs) following cladribine treatment. Settings and Design: Clinical presentation, peripheral smear, bone marrow aspiration and biopsy of HCL cases diagnosed over a period of three years were reviewed. Materials and Methods: Consecutive HCL cases in Hematology clinic of a tertiary care center were enrolled. Tartarate-resistant acid phosphatase (TRAP) test was done to detect HCs and electron microscopy was done to demonstrate initial ultrastructural changes and alterations following cladribine therapy. Results: Fifteen cases of HCL, aged 32-57 years (median 47 years) were studied. The clinical presentation included splenomegaly in 15 (100%), fever in 10 (67%), hepatomegaly and pain abdomen in eight (53%), fatigue in nine (60 %) cases. The commonest laboratory features were monocytopenia in 13 (87%), neutropenia in 12 (80%), anemia in 10 (67 %) and pancytopenia in nine (60%). All patients showed symptomatic improvement on cladribine therapy. Electron microscopy after treatment (three months) showed loss of the finger like projections, characteristic bald lymphocytes, loss of ribosomal lamellar complexes, as well as decrease in mitochondria and vacuoles. Conclusions: Indian patients with HCL are younger. Cladribine is an effective therapy for these patients and leads to complete response in most of the patients. There is a significant improvement in the ultrastructural features following cladribine therapy.     

Intermittent 2-hour-infusion of cladribine as first-line therapy or in first relapse of progressive advanced low-grade and mantle cell lymphomas.

Aim of this multicenter-study was to evaluate rate and duration of remissions and to examine toxicity of cladribine in low-grade lymphomas as first-line therapy or in first relapse using intermittent 2-hour-infusion of cladribine. A total of 294 courses, median of 5 courses per patient, were administered to 66 evaluable patients (53 previously untreated, 13 relapsed) with 5 mg/m2 cladribine given as intermittent 2-hour-infusion over 5 consecutive days for a maximum of 6 cycles every four weeks. Entities: 26 follicle center, 20 lymphoplasmacytoid, 12 mantle cell, 6 T-cell, 2 marginal zone lymphomas. Fifty of 66 patients responded to cladribine corresponding to an overall response rate of 76% (95% confidence interval (95% CI): 64%-85%) with 38% CR (95% CI: 26%-51%) and a median time of remission duration of 23 months (range 6-45+). The overall survival rate at 48 months was 72%. For 49 previously untreated patients with B-cell lymphomas the overall response rate was 86% (95% CI: 73%-94%) with a high CR rate of 43% (95% CI: 29%-58%). Response rate for the group of 23 previously untreated patients with follicle center lymphomas was high with 96% overall response (95% CI: 78%-100%) and 57% CR rate (95% CI: 34%-77%). Cladribine also showed activity in patients with mantle cell lymphomas achieving a response rate of 58% (95% CI: 28%-85%). Myelosuppression was the major toxicity with 17% neutropenia grade 3 and 4. Thrombocytopenia was rare with only 2% grade 3 and 4. A prolonged CD4-lymphocytopenia was observed in all patients. Life threatening complications were not observed. These results confirm the major single-agent activity of cladribine in a large cohort of patients with untreated low-grade lymphomas using the intermittent 2-hour-infusion dosage-regimen. To improve treatment results furthermore, cladribine should be combined with other agents active in low-grade lymphomas.     

Delayed onset of autoimmune hemolytic anemia complicating cladribine therapy for Waldenström macroglobulinemia

Therapeutic options for patients with Waldenstr?m macroglobulinemia (WM) now include the purine nucleoside analogues, fludarabine and cladribine. Both these agents have been associated with the onset of severe life-threatening autoimmune hemolytic anemia (AIHA) in patients with chronic lymphocytic leukemia (CLL). In these reports, AIHA developed within 6 weeks of drug administration and was generally resistant to conventional therapy. AIHA following purine analogues has not been reported in other hematologic malignancies. We report here on 4 patients with WM who developed AIHA following cladribine therapy. Cladribine was administered as a 2-hour infusion at a dose of 0.12 mg/kg per day for 5 consecutive days, at 28-day intervals. The median number of cycles was four (range, 4 to 6). AIHA occurred at a median of 40 months (range, 24 to 60) from cladribine administration. Only 1 patient responded to oral steroids while the other 3 were resistant to multiple therapeutic interventions. Two patients, 1 in complete remission and 1 requiring transfusional support, remain alive, and 2 have died. In contrast to published reports of the early onset of AIHA occurring after purine analogues in CLL patients, we observed AIHA in WM patients as a delayed event.     

克拉屈滨治疗18例复治惰性B细胞淋巴瘤的临床分析

探讨克拉屈滨用于复治惰性B细胞淋巴瘤的有效率及安全性。方法:回顾性分析2009年12月至2011年4月本院淋巴肿瘤科使用克拉屈滨治疗的18例惰性B细胞淋巴瘤患者的疗效及安全性。结果:18例患者中中位发病年龄54.5岁,临床分期为Ⅲ～Ⅳ期占88.3%,10例患者使用过2种或2种以上化疗方案,使用克拉屈滨之前的平均化疗周期数11.6个,中位数为8个周期（2～57个）。13例患者完成2个周期或以上克拉屈滨联合环磷酰胺（CC）方案化疗,5例患者仅使用1个周期化疗,总有效率27.8%,完全缓解率（CR）16.7%。骨髓抑制为主要不良反应,3～4级粒细胞减少症发生率为33.3%。结论:克拉屈滨对复发惰性B细胞淋巴瘤显示出一定的有效率,安全性良好。      

Randomized comparison of cladribine alone or in combination with cyclophosphamide, and cyclophosphamide, vincristine and prednisone in previously untreated low-grade B-cell non-Hodgkin lymphoma patients: final report of the Polish Lymphoma Research Group

BACKGROUND: The objective of this study was to compare the efficacy of 3 regimens, cladribine alone, cladribine and cyclophosphamide combination, or cyclophosphamide, vincristine, and prednisone combination in previously untreated patients with low-grade B-cell non-Hodgkin lymphoma (LGNHL). METHODS: For this 3-arm, phase 3 study, 197 patients were randomly allocated to receive 6 monthly courses of cladribine alone, cladribine and cyclophosphamide combination, or cyclophosphamide, vincristine, and prednisone combination. Patients for whom all clinical data were available and 162 patients who completed scheduled chemotherapy were analyzed for the endpoints of this study. RESULTS: Compared with cyclophosphamide, vincristine, and prednisone combination regimen, cladribine alone or cladribine and cyclophosphamide combination induced higher probability of overall response (odds ratio [OR] = 4.0; 95% confidence interval [CI], 1.7-9,3; P = .002, and OR = 8.5; 95% CI, 3.2-22.7; P < .0001, respectively), complete remission (OR = 5.8; 95% CI, 1.8-18.5; P = .003; and OR = 14; 95% CI, 4.4-44; P < .0001, respectively), progression-free survival (log-rank test P < .0001), but not overall survival. After incorporating the International Prognostic Index in multivariate analysis, treatment with cladribine-containing regimens remained an independent prognostic factor for progression-free survival (chi(2) = 35.94; hazard ratio = 2.38; P < .0002). Incidences of infections were similar in the randomized groups, whereas cladribine and cyclophosphamide combination, but not cladribine alone, induced more frequent neutropenia, anemia, and thrombocytopenia compared with cyclophosphamide, vincristine, and prednisone combination (P < .05 for each). This resulted in a higher frequency of prolongation of intervals between cladribine and cyclophosphamide combination and cyclophosphamide, vincristine, and prednisone combination cycles (P < .05), but dose reductions due to hematological or other toxicity did not differ significantly in cladribine alone, cladribine and cyclophosphamide combination, and cyclophosphamide, vincristine, and prednisone combination groups. CONCLUSIONS: For patients with LGNHL, first-line cladribine alone or cladribine and cyclophosphamide combination regimens both provided similar treatment responses, acceptable toxicity, and better response rates than cyclophosphamide, vincristine, and prednisone combination.     

A phase II study of cladribine treatment for fludarabine refractory B cell chronic lymphocytic leukemia: results from CALGB Study 9211.

Cladribine has been reported to have little activity in fludarabine- refractory chronic lymphocytic leukemia (CLL). We sought to determine whether resistance to therapy with cladribine in fludarabine-refractory CLL patients represented primary drug resistance or the inability to tolerate the myelosuppression associated with this therapy. Patients with fludarabine refractory CLL patients without severe thrombocytopenia (platelets >/=50 x 10(9)/l) or granulocytopenia (neutrophils >1.5 x 10(9)/l) were enrolled. All patients received cladribine (0.14 mg/kg) as a 2-h intravenous infusion daily for 5 days, repeated every 4 weeks. Patients received up to six cycles of therapy. Twenty-eight patients enrolled; 13 had intermediate (Rai stage I or II) and 15 high (Rai stage III and IV) risk stages. No patient had a complete remission, but nine (32%; 95% confidence interval, 15-49%) attained a partial remission when assessed using the modified NCI criteria (1996). The median time to relapse for responders was 12 months, while median progression-free survival for the entire group was 9 months (95% confidence interval, 4-14 months). The median overall survival was 2.2 years (95% confidence interval, 0.8-3.1 years). Response was predicted by pre-treatment Rai status with seven of 13 (54%) intermediate risk vs two of 15 (13%) high-risk patients responding (P = 0.04). Toxicity was myelosuppression and infections (grade 3-5: neutropenia 75%, thrombocytopenia 68%, and infections 43%). Cladribine has modest clinical activity and considerable toxicity in a very selected group of patients with fludarabine-refractory CLL lacking pre-treatment neutropenia and thrombocytopenia.     

Activity and toxicity of 2-CDA in Langerhans cell histiocytosis: a single institutional experience

BACKGROUND: Langerhans cell histiocytosis (LCH) is a rare disorder characterized by clonal proliferation of immature and abnormal bone marrow derived langerhans cells. Treatment is usually multimodal. Potent anti-monocyte as well as immunomodulatory activity of 2-CDA and its proven efficacy in many lymphoproliferative disorders has made 2-CDA a rational choice in treatment of LCH. AIM: To evaluate the efficacy and toxicity profile of 2-CDA in children with relapsed or refractory LCH. SETTING AND DESIGN: This is a pilot study and we present the initial data of the first seven patients treated at our institution. MATERIALS AND METHODS: Seven patients of relapsed and refractory LCH were enrolled from July 2000 to June 2004. The cohort of seven patients included six males and one female with a median age at initiation of cladribine was 2.25 years (range, 1.67 to 7.0 years). Three patients had received one prior chemotherapy regimen while the rest were heavily pretreated. Cladribine was administered over two hours IV daily for five days and repeated every four weeks. RESULTS: After a median of six courses of cladribine (range, 2 to 9), two (33%) patients achieved PR and two (33%) patients have SD on imaging but are clinically better. None experienced grade 3 or 4 hematologic toxicity. At a median follow-up of 19 months (range, 8 to 52 months), five patients remain alive and one patient has died. CONCLUSION: Our study shows that single agent 2-CDA is active and well-tolerated in children with relapsed or refractory LCH.     

Reduced dose of subcutaneous cladribine induces identical response rates but decreased toxicity in pretreated chronic lymphocytic leukaemia

Purpose: To study the efficacy and the safety of cladribine (2-chlorodeoxyadenosine, 2-CDA) administered as 24-hour infusions or as subcutaneous bolus injections at two different doses to patients with relapsing or refractory chronic lymphocytic leukaemia (CLL).Patients and methods: In this non randomised 2-cohort study, 20 patients with pretreated CLL received cladribine at a dose of 0.7 mg/kg/cycle as continuous i.v. infusions over seven days (group 1) and 35 patients were treated at a reduced dose of 0.5 mg/kg/cycle given as s.c. bolus injections for five days (group 2). After two cycles of four week duration, response was assessed. In the case of progressive disease, therapy was discontinued, otherwise a maximum of four additional cycles were administered until best response.Results: A total of 130 cycles were administered (group 1: 41, group 2: 89). Patient characteristics in both groups were comparable. The median dose intensities were 0.172 mg/kg per week and 0.123 mg/kg per week for groups 1 and 2, respectively (P 0.0001). The overall response rate for all 55 patients was 38% (95% confidence interval (95% CI): 25%–52%), with 5% CR and 33% PR. Response was similar in both patient groups (35% in group 1, 40% in group 2). No association between cladribine dose intensity and response rate was found, and there was no difference between patients relapsing after or refractory to previous therapies (11 of 24 vs. 10 of 31). Median remission duration was six months in both groups. Toxicity, in particular infections (all WHO grades, 34% in group 1 versus 7% in group 2) and myelosuppression (grade 1–4 neutropenia, 72% versus 41% of cladribine cycles) were statistically significantly more frequent in group 1.Conclusion: Cladribine is active in heavily pretreated patients with chronic lymphocytic leukaemias. Dose reduction by 29% led to similar response and remission duration, but to a significant decrease of myelotoxicity and risk of infection. Cladribine administered as s.c. bolus injections at 0.5 mg/kg per cycle is safe and this dose level should not be exceeded in this patient population.