Comparison of chlorambucil and prednisone versus cyclophosphamide, vincristine, and prednisone as initial treatment for chronic lymphocytic leukemia: long-term follow-up of an Eastern Cooperative Oncology Group randomized clinical trial

The road to chemotherapy-free treatment in chronic lymphocytic leukaemia

PURPOSE OF REVIEW

The treatment landscape of chronic lymphocytic leukaemia (CLL) has tremendously evolved in the last decades, from chemo to chemoimmunotherapy (CIT) and, eventually, to pathway inhibitors that target critical pathways for leukaemic cells survival. Also, treatment goals are moving towards achieving undetectable minimal residual disease with little toxicity.

RECENT FINDINGS

We performed a thorough review of the history of treatment approvals by both the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). This review especially focuses on therapies that are currently approved by both agencies. The indications and particular characteristics of each drug are examined.

SUMMARY

Currently available treatment approaches for CLL offer the opportunity to individualize therapy for every single patient with CLL. Inhibitors of B-cell receptor (BCR) signalling pathways and antiapoptotic proteins are nowadays the treatment of choice for most CLL patients, but CIT can be an option for younger and fit patients with low-risk disease [mutated IGHV, no del(11q) or del(17p)/TP53 mutations].

Nitrogen Mustards as Anticancer Chemotherapies: Historic Perspective, Current Developments and Future Trends

Nitrogen mustards, a family of DNA alkylating agents, marked the start of cancer pharmacotherapy. While traditionally characterized by their dose-limiting toxic effects, nitrogen mustards have been the subject of intense research efforts, which have led to safer and more effective agents. Even though the alkylating prodrug mustards were first developed decades ago, active research on ways to improve their selectivity and cytotoxic efficacy is a currently active topic of research. This review addresses the historical development of the nitrogen mustards, outlining their mechanism of action, and discussing the improvements on their therapeutic profile made through rational structure modifications. A special emphasis is made on discussing the nitrogen mustard prodrug category, with Cyclophosphamide (CPA) serving as the main highlight. Selected insights on the latest developments on nitrogen mustards are then provided, limiting such information to agents that preserve the original nitrogen mustard mechanism as their primary mode of action. Additionally, future trends that might follow in the quest to optimize these invaluable chemotherapeutic medications are succinctly suggested.

Remission maintenance treatment options in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) treatment has come a long way in the last two decades, producing increases in tumor control to the point of generating sizeable numbers of patients with undetectable minimal residual disease and creating overall survival benefits in randomized comparisons. Most of this has been achieved by limited-term treatment approaches including chemotherapeutic and immune-therapeutic drugs. More recently, novel therapies targeting signaling pathways essential for the survival of the neoplastic clones have opened avenues that provide disease control in long-term treatment designs, mostly without producing deep remissions. In this disease, where current treatments are largely unable to effect a cure, prolonged therapy designs using maintenance approaches are explored and 5 randomized studies of maintenance have recently been published. This review shall summarize available results from a systematic literature review in a clinical context and outline basic biology principles that should be heeded in this regard.

Effectiveness of Fludarabine in Advanced B-Cell Chronic Lymphocytic Leukemia

Aims

The study was carried out to investigate the efficacy and toxicity of fludarabine phosphate in the treatment of B-cell chronic lymphocytic leukemia (B-CLL) in previously treated patients.

Methods

Sixteen patients, 11 males and 5 females, 9 in stage B and 7 in stage C, according to the Binet Staging System, were treated with a maximum of 6 cycles of fludarabine (25 mg/m2) for 5 days, every 4 weeks. All patients had been pretreated, 10 were refractory to standard regimens, 5 were in relapse, and 1 patient was in partial remission.

Results

Thirteen patients were judged suitable for evaluation. Overall 9 patients were responsive to treatment; 4 complete and 5 partial responses were observed. Of the 4 patients in complete remission, 3 were alive at 6, 10 and 13 months, respectively, from the beginning of treatment. One patient died after 11 months for acute graft-versus-host disease after allogenic bone marrow transplantation by an HLA sibling donor. Two of the 5 patients in partial remission were alive at 7 and 17 months, respectively, and the other 3 died (2 of disease reexpansion after 14 and 16 months and 1 of septic shock following pneumonia). Four patients were not responsive to treatment: 1 died from disease progression after 8 months from the beginning of therapy, 1 from cardiac failure after 9 months, 1 from septic shock following meningitis, and 1 was alive after 7 months of follow-up. Treatment was well tolerated, with nausea and vomiting in only one patient. We observed two episodes of pneumonitis, without any evidence of the responsible agent, a tumor lysis syndrome with acute renal failure, a recurrence of autoimmune thrombocytopenia, and a Coombs-positive hemolytic anemia.

Conclusions

Fludarabine phosphate is effective in the treatment of patients with advanced B-CLL, even in those refractory to multiple chemotherapy regimens.

Initial therapy of chronic lymphocytic leukemia

Only chronic lymphocytic leukemia (CLL) patients with active or symptomatic disease or with advanced Binet or Rai stages require therapy. Prognostic risk factor profile and comorbidity burden are most relevant for the choice of treatment. For physically fit patients, chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab remains the current standard therapy. For unfit patients, treatment with an anti-CD20 antibody (obinutuzumab or rituximab or ofatumumab) plus milder chemotherapy (chlorambucil) may be applied. Patients with a del(17p) or TP53 mutation should be treated with the kinase inhibitors ibrutinib or a combination of idelalisib and rituximab. Clinical trials over the next several years will determine, whether kinase inhibitors, other small molecules, immunotherapeutics, or combinations thereof will further improve outcomes for patients with CLL.

Cost Effectiveness of Ofatumumab Plus Chlorambucil in First-Line Chronic Lymphocytic Leukaemia in Canada

OBJECTIVE

Our objective was to estimate the cost effectiveness of ofatumumab plus chlorambucil (OChl) versus chlorambucil in patients with chronic lymphocytic leukaemia for whom fludarabine-based therapies are considered inappropriate from the perspective of the publicly funded healthcare system in Canada.

METHODS

A semi-Markov model (3-month cycle length) used survival curves to govern progression-free survival (PFS) and overall survival (OS). Efficacy and safety data and health-state utility values were estimated from the COMPLEMENT-1 trial. Post-progression treatment patterns were based on clinical guidelines, Canadian treatment practices and published literature. Total and incremental expected lifetime costs (in Canadian dollars [$Can], year 2013 values), life-years and quality-adjusted life-years (QALYs) were computed. Uncertainty was assessed via deterministic and probabilistic sensitivity analyses.

RESULTS

The discounted lifetime health and economic outcomes estimated by the model showed that, compared with chlorambucil, first-line treatment with OChl led to an increase in QALYs (0.41) and total costs ($Can27,866) and to an incremental cost-effectiveness ratio (ICER) of $Can68,647 per QALY gained. In deterministic sensitivity analyses, the ICER was most sensitive to the modelling time horizon and to the extrapolation of OS treatment effects beyond the trial duration. In probabilistic sensitivity analysis, the probability of cost effectiveness at a willingness-to-pay threshold of $Can100,000 per QALY gained was 59 %.

CONCLUSIONS

Base-case results indicated that improved overall response and PFS for OChl compared with chlorambucil translated to improved quality-adjusted life expectancy. Sensitivity analysis suggested that OChl is likely to be cost effective subject to uncertainty associated with the presence of any long-term OS benefit and the model time horizon.

Obinutuzumab treatment in the elderly patient with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults in Western countries. Fludarabine-based regimens demonstrate higher response rates in younger patients but have a significant risk of infection and are thus poorly tolerated by older, frail patients. Anti-CD20 monoclonal antibodies have added to the efficacy of chemotherapy in CLL. Obinutuzumab is a potent Type II anti-CD20 monoclonal antibody with enhanced antibody-dependent cellular toxicity and direct cell death compared with rituximab. In Phase I studies, infusion reactions and neutropenia were the predominant toxicities. Phase II studies demonstrated efficacy both as a single agent and in combination with chemotherapy in patients with CLL. The CLL11 trial was a Phase III randomized trial of chlorambucil alone or with either obinutuzumab or rituximab in elderly, unfit patients. Progression-free survival (the primary end point) was 26.7 months for patients receiving obinutuzumab plus chlorambucil versus 16.3 months for those receiving rituximab plus chlorambucil and 11.1 months for those receiving chlorambucil alone (P<0.001). Overall survival was improved for patients receiving obinutuzumab plus chlorambucil versus chlorambucil alone (P=0.002). This trial led to the US Food and Drug Administration (FDA) approval of obinutuzumab in this patient population.

Past, present and future role of chlorambucil in the treatment of chronic lymphocytic leukemia

For many decades, chlorambucil was the standard of care for chronic lymphocytic leukemia (CLL), but meanwhile has been replaced by purine analog-based chemoimmunotherapy. Monotherapy with the alkylator only retained significance in the treatment of older patients unfit for standard treatment. After successful phase II studies, recent phase III trials established combinations of chlorambucil with anti-CD20 antibodies such as rituximab, ofatumumab and obinutuzumab as a valuable treatment option for these patients. Today, chlorambucil therefore should be used as a chemotherapy backbone for antibody-based chemoimmunotherapy in this patient population rather than as monotherapy. Starting from the past role of chlorambucil in CLL treatment, we here review the most recent efforts to elaborate chlorambucil-based chemoimmunotherapy in CLL and discuss clinically relevant questions that arise from this approach.

Pharmacokinetic evaluation of vincristine for the treatment of lymphoid malignancies

INTRODUCTION

Vincristine is a key agent for the treatment of acute lymphoblastic leukemia (ALL) and other lymphoid malignancies. The strong antineoplastic activity of vincristine has been limited by its pharmacological characteristics.

AREAS COVERED

This paper reviews the role of vincristine in the treatment of lymphoid malignancies. This review summarizes its efficacy and toxicity, and focuses on the pharmacokinetic features of vincristine that affect clinical outcomes.

EXPERT OPINION

As a single agent, vincristine is associated with brief and incomplete responses, but in combination with other agents, vincristine has dramatically improved the outcomes of lymphoid malignancies such as ALL. Vincristine is a key drug of hyper-fractionated cyclophosphamide, vincristine, doxorubicin and dexamethasone, an intensive chemotherapeutic regimen for the treatment of ALL, and of cyclophosphamid, adriamycin, vincristine and prednisone, which has been used extensively in the treatment of patients with aggressive or indolent lymphomas and Richter syndrome. The strong antileukemic activity of vincristine has been limited by its variable and unpredictable pharmacological characteristics, narrow therapeutic index and neurotoxicity profile. These characteristics prompted the development of liposomal vincristine, which has optimized its clinical application. Liposomal vincristine has promising antileukemic activity, and it is approved by the FDA as a single agent for the treatment of relapsed/refractory Philadelphia chromosome-negative ALL.

The promising impact of ibrutinib, a Bruton's tyrosine kinase inhibitor, for the management of lymphoid malignancies

Lymphoid malignancies comprise a heterogeneous group of disorders originating from clonal proliferation of B or T lymphocytes. Treatment of lymphoid neoplasms has traditionally been pursued with cytotoxic chemotherapy. To improve efficacy and ameliorate the adverse effects associated with classic chemotherapy, molecularly targeted therapy has been developed. At the forefront of clinical development is ibrutinib, an inhibitor of Bruton's tyrosine kinase (Btk). Btk is a protein tyrosine kinase that plays an important role in regulating B-cell signaling. Dysregulated Btk results in uncontrolled B-lymphocyte proliferation, differentiation, and survival. Ibrutinib is currently being studied in numerous malignancies of lymphoid origin including chronic lymphocytic leukemia, mantle cell lymphoma, non-Hodgkin lymphoma, follicular lymphoma, and multiple myeloma. Thus far, ibrutinib has demonstrated very promising results in treatment-naive patients as well as those with relapsed or refractory disease with an acceptable safety profile. In this article, we describe the pharmacology, efficacy, and toxicity profile of ibrutinib and depict the potential role that ibrutinib will play in the treatment paradigm of lymphoid neoplasms.

Chronic lymphocytic leukemia in India-A clinico-hematological profile

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in elderly people. The clinico-hematological profile and treatment outcome of patients with CLL were assessed using retrospective case record analysis over 11 years. There were 95 (75 males: 20 females) patients with a median age of 61 years. Thirty patients were aged 55 years or less (young CLL patients) and 65 were more than 55 years of age (elder CLL patients). Sixty percent patients had non-specific complaints, such as weakness, cough and indigestion. Twenty-six (27%) patients had pallor and 24 (25%) had fever as initial presenting manifestation. Bleeding manifestations were seen in 7 patients. Seven patients were diagnosed incidentally. Lymphadenopathy, splenomegaly and hepatomegaly were seen in 52 (55%), 63 (66%) and 60 (63%) patients, respectively. The median white blood cell count and absolute lymphocyte counts were 70,600 and 51,490/mul, respectively. Three patients had autoimmune hemolytic anemia. Twenty-five patients (26%) had anemia with hemoglobin < 11 g/dl and thrombocytopenia with platelet count 100 x 10(3)/mm(3) was seen in 17 (18%). Interstitial nodular, mixed and diffuse bone marrow (BM) involvement was seen in 10.2, 67.3, 6.1 and 16.3% cases, respectively. Eighteen (60%) young patients and 35 (54%) older patients required treatment with chlorambucil. The mean time from initial diagnosis to treatment was 4.6 +/- 10.7 months. None of our patient attained complete response. Six patients obtained partial response. Median duration of chlorambucil was 7 months (1-86 months). Forty-six patients had stable disease. Three patients died. Median survival of study group was 4 years (8 months-13 years). In older CLL it was 4 years (8 months-11 years) and in young patients, survival duration was 5.5 years (1-13 years).

Non-Hodgkin lymphoma

Lymphomas are solid tumours of the immune system. Hodgkin's lymphoma accounts for about 10% of all lymphomas, and the remaining 90% are referred to as non-Hodgkin lymphoma. Non-Hodgkin lymphomas have a wide range of histological appearances and clinical features at presentation, which can make diagnosis difficult. Lymphomas are not rare, and most physicians, irrespective of their specialty, will probably have come across a patient with lymphoma. Timely diagnosis is important because effective, and often curative, therapies are available for many subtypes. In this Seminar we discuss advances in the understanding of the biology of these malignancies and new, available treatments.

Treatment and management of chronic lymphocytic leukemia in the elderly: what the pharmacist clinician should know

OBJECTIVE

To review the literature for current treatment options and supportive care management for elderly patients with chronic lymphocytic leukemia (CLL).

DATA SOURCES

PubMed searches using the terms chronic lymphocytic leukemia, elderly, practice guidelines, and controlled clinical trials were performed from 1949 through August 2011. Reference lists from relevant articles were examined for additional studies, review articles, and guidelines.

STUDY SELECTION AND DATA EXTRACTION

Eighty-three articles were generated and abstracted articles were chosen based on trial results that changed clinical practice, resulted in approval of new drugs for CLL by the Food and Drug Administration and/or had clinical relevance to the elderly population.

DATA SYNTHESIS

Fit elderly CLL patients have more treatment options than frail elderly. Most studies include patients younger than 65 years of age, and recent advances in treatment may not prove beneficial for all ages. Clinicians should use available evidence and clinical judgment when treating and monitoring elderly CLL patients.

CONCLUSION

Treatment armamentarium has improved over the last decade, yet clinical trials research should include more elderly cohorts as new agents are developed. Increased awareness of supportive care issues improves quality of life for a population with multiple disease complications.

Choosing first-line therapy for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) exhibits a highly variable natural history, but the addition of genomic risk stratification to traditional clinical staging systems has begun to explain the heterogeneous clinical course. Overall response to treatment has significantly improved over the past three decades and for the first time, a survival benefit has been demonstrated with the use of monoclonal antibodies in combination with cytotoxic chemotherapy. Newer therapeutic strategies have abrogated the adverse prognosis associated with some higher risk features, but other genetic subgroups remain at high risk for rapid disease progression and early mortality. Patients at advanced age or with significant comorbidity constitute a large proportion of the CLL population and present unique clinical challenges. This article will discuss the evolution of contemporary therapeutic approaches to the initial treatment of CLL, and highlight the ways in which risk-adapted therapeutic strategies are improving clinical outcomes.

Current and emerging treatments for chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common adult leukaemia in Europe and North America. The disease is characterized by proliferation and accumulation of small CD5+ B cells in blood, lymph nodes, spleen, liver and bone marrow. The natural clinical course of CLL is highly variable, and chemotherapy is usually not indicated in early and stable disease. However, patients with progressive and more advanced CLL require treatment. For many years, chlorambucil with or without corticosteroids was used in previously untreated patients with CLL. More recently, purine nucleoside analogues (PNAs) [fludarabine, cladribine and pentostatin] have been included in treatment approaches for this disease, and chlorambucil is no longer the leading standard everywhere. Currently, this drug is rather recommended for the treatment of older, unfit patients with co-morbidities, especially in European countries. Significantly higher overall response (OR) and complete response (CR) rates in patients treated initially with PNAs than in those treated with chlorambucil or cyclophosphamide-based combination regimens have been confirmed in randomized, prospective, multicentre trials. Moreover, PNAs administered in combination with cyclophosphamide produce higher response rates, including CR and molecular CR, compared with PNA as monotherapy. Recent reports suggest that the administration of monoclonal antibodies (mAbs) can significantly improve the course of CLL. At present, two mAbs have the most important clinical value in patients with CLL. The first is rituximab, a human mouse antibody that targets CD20 antigens, and the second is alemtuzumab, a humanized form of a rat antibody active against CD52. Several recent reports suggest that in patients with CLL, rituximab combined with a PNA can increase the OR and CR rates compared with PNA or rituximab alone, with acceptable toxicity. In randomized trials, the combination of rituximab with fludarabine and cyclophosphamide (FC-R regimen) demonstrated higher rates of OR, CR and progression-free survival in patients with previously untreated and relapsed or refractory CLL than fludarabine plus cyclophosphamide (FC regimen). Several reports have confirmed significant activity with alemtuzumab in relapsed or refractory CLL, as well as in previously untreated patients. Recently, several new agents have been investigated and have shown promise in treating patients with CLL. These treatments include new mAbs, agents targeting the antiapoptotic bcl-2 family of proteins and receptors involved in mediating survival signals from the microenvironment, antisense oligonucleotides and other agents. The most promising are new mAbs directed against the CD20 molecule, lumiliximab and anti-CD40 mAbs. Oblimersen, alvocidib (flavopiridol) and lenalidomide are also being evaluated both in preclinical studies and in early clinical trials. In recent years, a significant improvement in haematopoietic stem cell transplantation (HSCT) procedures in patients with high-risk CLL has been observed. However, the exact role of HSCT, autologous or allogeneic, in the standard management of CLL patients is still undefined.

Bendamustine: a new treatment option for chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a slow-growing hematologic malignancy and the most common type of leukemia in the western world. The lifetime risk for developing CLL is 1 in 216 men and women. Unfortunately, CLL is considered incurable with the chemotherapeutic agents available today. Bendamustine is a new agent that was recently added to the available regimens for the treatment of CLL. It was also recently approved for the treatment of non-Hodgkin's lymphoma. Its mechanism of action is unknown, but it contains an alkylating group similar to that of other bifunctional alkylating agents such as chlorambucil, and it also contains a benzimidazole central ring thought to exhibit antipurine-like properties. The United States Food and Drug Administration approved bendamustine based on results from an international phase III study of CLL in which bendamustine was compared with chlorambucil in treatment-naïve patients. Ongoing clinical trials are assessing the utility of bendamustine in combination with other agents for the treatment of CLL, as well as for other malignancies.

A review of pharmacologic options for previously untreated chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia and has a heterogeneous clinical course. Some patients experience an indolent disease course, which does not require treatment or affect their overall quality of life. Other patients present with symptomatic advanced disease that rapidly progresses and requires therapy. For these patients, chemotherapy is the mainstay of treatment and has undergone significant evolution in the past few decades. From alkylating agents to purine analogs, response rates have greatly improved with new chemotherapy regimens. The development of chemoimmunotherapy regimens has also transformed the treatment of CLL. This article will review front-line treatment options for CLL and discuss the updated National Comprehensive Cancer Network guidelines.

Improved survival in chronic lymphocytic leukemia in the past decade: a population-based study including 11,179 patients diagnosed between 1973-2003 in Sweden

BACKGROUND

Clinical management of chronic lymphocytic leukemia patients has changed considerably over the last years, reflected in an increased use of prognostic markers, new therapeutic agents and procedures, and supportive care measures. However, to date, clinical trials have not shown a survival benefit.

DESIGN AND METHODS

Using population-based data from Sweden, we assessed variations in survival among all chronic lymphocytic leukemia patients (n=11,179) reported from 1973-2003. Relative survival ratios were computed as measures of patient survival.

RESULTS

Overall we found significantly improved (p<0.0001) 5-, 10-, and 20-year relative survival ratio for the entire cohort during the study period. Improved 5- and 10-year relative survival ratio was found for all age-groups (p<0.0001) and both sexes. Compared to females, however, males had a significantly inferior survival in all age groups and calendar periods (p<0.0001). Younger chronic lymphocytic leukemia patients had a superior survival compared to older chronic lymphocytic leukemia patients, in all calendar periods (p<0.0001). Five-year relative survival ratio has not improved in the youngest chronic lymphocytic leukemia patients since the 1980s; however, older patients have had a continuous improvement in 5 year-relative survival ratio.

CONCLUSIONS

The observed improvements are likely due to improved therapeutic developments and supportive care. Our findings suggest that elderly chronic lymphocytic leukemia patients might benefit more from the recently introduced drugs in chronic lymphocytic leukemia. Future clinical trials are needed to better define underlying mechanisms of observed heterogeneity in chronic lymphocytic leukemia survival by age and sex, and evaluate the role of newer chronic lymphocytic leukemia therapy in the elderly.

Pentostatin, Chlorambucil and Prednisone Therapy for B-Chronic Lymphocytic Leukemia: A Phase I/II Study by the Eastern Cooperative Oncology Group Study E1488

Pentostatin is a purine nucleoside analog with demonstrated activity in low-grade lymphoid malignancies. The purpose of this study was to determine the dose of pentostatin (dCF) that could be combined with chlorambucil and prednisone to treat chronic lymphocytic leukemia (CLL), evaluate the toxicity of the resulting regimen and to estimate its efficacy. This was a multi-institutional Eastern Cooperative Oncology Group (ECOG) phase I-II study. Individuals with active B-CLL were eligible if they had no prior treatment or were in sensitive first relapse, provided they had normal renal and hepatic function. Pentostatin was evaluated in combination with orally administered chlorambucil 30 mg/m2 and prednisone 80 mg/day, 1-5 of each 14-day cycle. The pentostatin dose was 2 mg/m2 IV, day 1 for the first 6 patients; 3 mg/m2 IV, day 1 for the next 6 patients; and 4 mg/m2 IV, day 1 for the last set of 6 patients. Fifty-five patients were entered. Because of increasing toxicity with no apparent improvement in clinical efficacy on escalation of the pentostatin dose, 2 mg/m2 was chosen as the phase II dose, and 43 patients were treated at this level. Thirty-nine of these patients were eligible, of which 38 were evaluable for response, 36 of these 38 had no prior treatment. Complete response (CR) manifested by normal bone marrow morphology, peripheral blood counts and resolution of any lymphadenopathy or hepatosplenomegaly occurred in 17 patients (45%). The overall objective response rate was 87%. The median response duration was 33 months and the median survival 5 years. The median time to treatment failure is 32 months. Severe (Grade 3+) infections were seen in 31% of patients and included bacterial pneumonia (n = 4), Pneumocystis pneumonia (n = 1), fungal pneumonia (n = 2), urinary tract infection with sepsis (n = 1) and Herpes Zoster (n = 5). Overall, 11 patients had H. Zoster while on study. Due to toxicity, 33% of patients stopped therapy. Pentostatin, chlorambucil and prednisone is a highly active regimen in CLL but cannot be recommended in present form because of an unacceptable incidence of opportunistic infections. These findings add to other recent reports which suggest combination therapy with pentostatin and alkylators are active in B-CLL. However, these combination chemotherapies will need to be combined with appropriate addition of anti-bacterial and anti-viral prophylaxis to reduce infection risk for B-CLL patients.

Prolonging microtubule dysruption enhances the immunogenicity of chronic lymphocytic leukaemia cells

Cytotoxic chemotherapies do not usually mediate the expression of an immunogenic gene programme in tumours, despite activating many of the signalling pathways employed by highly immunogenic cells. Concomitant use of agents that modulate and complement stress-signalling pathways activated by chemotherapeutic agents may then enhance the immunogenicity of cancer cells, increase their susceptibility to T cell-mediated controls and lead to higher clinical remission rates. Consistent with this hypothesis, the microtubule inhibitor, vincristine, caused chronic lymphocytic leukaemia (CLL) cells to die rapidly, without increasing their immunogenicity. Protein kinase C (PKC) agonists (such as bryostatin) delayed the death of vincristine-treated CLL cells and made them highly immunogenic, with increased stimulatory abilities in mixed lymphocyte responses, production of proinflammatory cytokines, expression of co-stimulatory molecules and activation of c-Jun N-terminal kinase (JNK), p38 and nuclear factor kappa B (NF-kappaB) signalling pathways. This phenotype was similar to the result of activating CLL cells through Toll-like receptors (TLRs), which communicate 'danger' signals from infectious pathogens. Use of PKC agonists and microtubule inhibitors to mimic TLR-signalling, and increase the immunogenicity of CLL cells, has implications for the design of chemo-immunotherapeutic strategies.

Emerging therapy for chronic lymphocytic leukaemia

The presentation, clinical course and prognosis for chronic lymphocytic leukaemia (CLL) is diverse and strategies for therapy reflect this variability. Staging of the disease has assisted in deciding treatment options and more recently the cytogenetic, molecular and surrogate markers of the immunoglobulin heavy chain mutational status, CD38 and ZAP-70, have assisted in further risk stratification. Chemotherapy has been the mainstay of interventional therapy when required and the two most important classes of agents in the treatment of CLL are nucleoside analogues and alkylating agents. Combining these two groups of agents has significantly improved prognosis in this disease. More recently a number of novel agents have been applied to patients with CLL to determine if they represent better therapy. However, allogeneic stem cell transplantation offers perhaps the only realistic chance of a cure in this disease. Clinical trials are still needed to determine the timing and role of this promising treatment modality in the treatment of CLL and, where possible, combined with the emerging awareness of the disease biology, related biological markers and prognostic indicators.

Management of symptomatic, untreated chronic lymphocytic leukemia

Fludarabine-based regimens have become an increasingly popular first-line approach for symptomatic patients with chronic lymphocytic leukemia. Compared with chlorambucil, fludarabine alone or in combination with cyclophosphamide or rituximab yields higher response rates, higher complete remission rates, and more durable progression-free survival. Immunotherapy and chemoimmunotherapy also have the potential to increase the depth of remission as assessed by flow cytometry or molecular techniques. An overall survival advantage with any one particular regimen has not yet been demonstrated. Progress with fludarabine-based regimens, monoclonal antibodies, chemoimmunotherapy, and high-dose therapy for previously untreated patients is reviewed. Fluorescent in situ hybridization and immunoglobulin variable heavy-chain sequencing now permit more individualized risk assessment. Examples of possible treatment algorithms based on risk category are explored. How to tailor treatment based on these newer prognostic factors remains a central, as yet unanswered management question.

Combination chemoimmunotherapy with pentostatin, cyclophosphamide, and rituximab shows significant clinical activity with low accompanying toxicity in previously untreated B chronic lymphocytic leukemia

Building on the prior work of use of pentostatin in chronic lymphocytic leukemia (CLL), we initiated a trial of combined pentostatin (2 mg/m2), cyclophosphamide (600 mg/m2), and rituximab (375 mg/m2) for 65 symptomatic, previously untreated patients. Of 64 evaluable patients, 34 (53%) were high Rai risk, 71% were nonmutated for the immunoglobulin heavy-chain variable region gene, 34% were CD38+, and 34% were ZAP-70+. Thirty patients (52%) had one anomaly detected by fluorescence in situ (FISH) hybridization, and 21 (36%) had complex FISH defects. Thirty-eight patients (58%) had grade 3+ hematologic toxicity but minimal transfusion needs and no major infections. Responses occurred in 58 patients (91%), with 26 (41%) complete responses (CRs), 14 (22%) nodular partial responses (nodular PRs), and 18 (28%) partial responses (PRs). Many patients with a CR also lacked evidence of minimal residual disease by 2-color flow cytometry. Examination of prognostic factors demonstrated poor response in the 3 patients with del(17p). In contrast, we found this regimen was equally effective in young versus older (>70 years) patients and in del(11q22.3) versus other favorable prognostic factors. Thus, this novel regimen of pentostatin, cyclophosphamide, and rituximab for previously untreated patients with CLL demonstrated significant clinical activity despite poor risk-based prognoses, achievement of minimal residual disease in some, and modest toxicity.

Recent advances in chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a low-grade B-lineage lymphoid malignancy. Based on recent findings, the disease appears to be more heterogeneous than previously thought. Many cases may require no treatment at all unless patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is noncurative and is directed at reducing the symptoms. Recently described molecular risk features may help delineate at initial diagnosis which patients will have a more aggressive course. Newer treatment regimens incorporating purine nucleoside analogs and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to increased survival. Reduced intensity conditioning regimens have made the potentially curative modality of allogeneic transplantation more widely available. All of these recent treatments have significant risks of infectious complications, which must be carefully weighed against the risks posed by the underlying disease, and many low-risk asymptomatic patients do not require any treatment. A proposed risk-based treatment algorithm will be discussed.

Purine Analogue-Based Chemotherapy Regimens for Patients With Previously Untreated B-Chronic Lymphocytic Leukemia

B-cell chronic lymphocytic leukemia (B-CLL) is a clonal malignancy characterized by the expansion of small B lymphocytes and accumulation of CLL cells. This disease is the most common form of leukemia in the Western hemisphere and is currently not considered to be curable using currently available therapies. Published reports have suggested that purine analogues have activity in B-CLL and superior to alkylating agents. Even though responses have been observed with purine analogues that are used as single agents, these responses were not durable. The use of combination purine analogue therapy with alkylating agents and/or monoclonal antibodies was then explored in order to take advantage of synergistic actions of these agents to improve the quality of clinical responses. Both fludarabine and pentostatin have shown improved responses when combined with alkylating agents and even higher overall and complete responses (CRs) when combined with monoclonal antibodies.

Chronic Lymphocytic Leukemia: Recent Advances in Diagnosis and Treatment

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy but may have more heterogeneity than previously thought. Many cases require no treatment at all because of an indolent course, while other patients become symptomatic or develop signs of rapid progression. Treatment is usually noncurative and is directed at reducing the symptoms. Some molecular risk features may help delineate, at initial diagnosis, which patients will have a more aggressive course. Newer CLL treatment regimens incorporating purine nucleoside analogues and monoclonal antibodies have increased the rate of molecular complete remissions, which may lead to better survival times. Reduced intensity allogeneic transplant conditioning regimens have made the potentially curative modality more widely available. All these treatments have significant risks for infectious complications, which must be carefully weighed against the risks posed by the underlying disease. A proposed risk-based treatment algorithm is discussed.

Advances in the diagnosis and treatment of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a low-grade B-lineage lymphoid malignancy, which is often not treated until patients become symptomatic or develop signs of rapid progression. Even in this setting, treatment is non-curative and is directed at reducing the symptoms from an increasing disease burden. Newer treatment regimens incorporating purine nucleoside analogs have increased the rate of successful remission induction in CLL patients. Recent combination chemoimmunotherapy regimens have produced frequent complete molecular remissions, and early evidence suggests this may result in an improved long-term survival. Allogeneic hematopoietic cell transplantation is the only curative therapy for CLL but is infrequently used due to the older age of most patients, although reduced intensity conditioning regimens have reduced the toxicity of allogeneic transplantation. This review will summarize recent advances in the management of CLL, including prognostic factors, combination chemotherapy including nucleoside analogs and monoclonal antibodies, and reduced intensity allogeneic transplant conditioning regimens.

Current guidelines in defining therapeutic strategies

The past three decades have brought major changes in the approach toward chronic lymphocytic leukemia (CLL). This disease was considered a simple form of leukemia for which the only goal of treatment was control of the leukocytosis and of the symptoms related to disease expansion. Many biologic discoveries have increased our understanding of the disease process. New prognostic markers have been identified and are being incorporated into clinical practice. Now, CLL is considered a complex and challenging leukemia for which multiple treatment options are emerging, from chemotherapy to monoclonal antibodies, from vaccines to immunomodulatory strategies. The evaluation of treatment results also has been revolutionized: clones carrying genetic aberrations are monitored, and patients who have had a response are assessed for the presence of minimal residual disease.

Advances in chemotherapy for chronic lymphocytic leukemia

While chemotherapy based on alkylating agents has been the standard treatment of chronic lymphocytic leukemia (CLL) for decades, purine analogues and their combinations have emerged as effective new therapies for previously untreated and pretreated patients. As single agents, fludarabine and cladribine are the most promising, showing higher remission rates compared to chlorambucil. For younger and physically fit patients, the combination of fludarabine and cyclophosphamide has shown benefit. Fludarabine plus epirubicin appears equally potent. The addition of monoclonal antibodies, such as rituximab and alemtuzumab, to purine analogues alone or in combination seems to be even more effective for chemotherapy-naive and pretreated CLL patients. Another promising agent in the armamentarium of therapies for CLL is bendamustine, which has properties of both an alkylating agent and a purine analogue. Clinical trials are ongoing with novel drugs that interfere with cell cycle regulation and signaling molecules in CLL, including flavopiridol, UCN-01, bryostatin 1, depsipeptide, and oblimersen. It remains to be seen whether these chemotherapeutic approaches offer real benefit for patients by prolonging survival with an improved quality of life.

Treatment of chronic lymphocytic leukemia

Treatment options for patients with chronic lymphocytic leukemia have changed over the past two decades. This article reviews the experience accumulated with the use of alkylating agents alone and in combination; purine analogues alone and in combination and monoclonal antibodies such as rituximab, and alemtuzumab alone and in combination. The results obtained with different treatment strategies are summarized, compared, and reviewed.

Chlorambucil in combination with induction and maintenance rituximab is feasible and active in indolent non-Hodgkin's lymphoma

We investigated the toxicity and efficacy of the chimaeric anti-CD20 antibody rituximab in combination with standard-dose chlorambucil in newly diagnosed and relapsed/refractory indolent B-cell lymphoma patients. A total of 29 patients (15 newly diagnosed and 14 relapsed/refractory) with low-grade or follicular B-cell non-Hodgkin's lymphoma (NHL) were included in this phase II study. Therapy consisted of chlorambucil 6 mg/m2/d for 6 consecutive weeks in combination with a standard 4-weekly rituximab administration schedule in the induction phase. Patients responding to the induction therapy received four additional cycles with chlorambucil (6 mg/m2/d for 2 weeks/month) plus rituximab (once a month). Twenty-six patients (89%) completed the treatment; only one patient discontinued treatment because of haematological toxicity. At the end of the study, the dose of chlorambucil had to be reduced in seven patients (27%) and six patients (23%) required a delay in further treatment, as a result of toxicity during consolidation therapy. Only one patient was withdrawn from the study because of progressive disease; the 27 patients evaluable for response at the end of consolidation achieved a clinical response (63% complete response and 26% partial response). A significant CD4+ and CD56+ depletion was observed after induction and during consolidation therapy; two herpes zoster virus infections and one perianal abscess represented major infectious morbidities registered during the study. Based on our preliminary data, the combination of chlorambucil with rituximab seemed to be well tolerated and active. Its definitive role in the treatment of low-grade NHL should be further evaluated in randomized trials.

Rituximab in B-cell chronic lymphocytic leukemia

The monoclonal anti-CD20 antibody rituximab exerts its antitumor activity through a variety of mechanisms, including acting against the cellular defects in apoptosis that give rise to B-chronic lymphocytic leukemia (B-CLL). Phase II clinical studies demonstrated that rituximab, given weekly as a single agent, exhibits significantly less activity in B-CLL than in indolent B-cell lymphomas. Dose escalation, achieved by a thrice-weekly dosing schedule, is necessary for rituximab to effect significant clinical activity as a single agent. A multicenter, prospective, randomized trial demonstrated that concurrent administration with fludarabine improves the complete response (CR) rate. Ongoing clinical studies are examining the use of rituximab in other combination regimens, including FCR (fludarabine, cyclophosphamide, and rituximab), which has shown great promise in a single-center phase II trial. B-CLL patients may experience more infusion toxicity, including tumor lysis syndrome, to rituximab than patients with lymphoma. However, such infusion toxicity is minimized with appropriate premedication and a stepped up dosing schedule, allowing safe and effective use of rituximab in this disease.

Biology and treatment of chronic lymphocytic leukemia

Major advances have occurred in our understanding of the biology, immunology, and opportunities for treatment of chronic lymphocytic leukemia (CLL) in recent times. Surface antigen analysis has helped us define classical CLL and differentiate it from variants such as marginal zone leukemia, mantle cell leukemia, and prolymphocytic leukemia. An important observation has been that the B-cells in indolent types of CLL, which do not require therapy, have undergone somatic hypermutation and function as memory B-lymphocytes whereas those more likely to progress have not undergone this process. Section I by Dr. Nicholas Chiorazzi encompasses emerging elements of the new biology of CLL and will address the types of somatic hypermutation that occur in CLL cells and their correlation with other parameters such as telomere length and ZAP70 status. In addition he addresses the concept of which cells are proliferating in CLL and how we can quantitate the proliferative thrust using novel methods. The interaction between these parameters is also explored. Section II by Dr. Thomas Kipps focuses on immune biology and immunotherapy of CLL and discusses new animal models in CLL, which can be exploited to increase understanding of the disease and create new opportunities for testing the interaction of the CLL cells with a variety of elements of the immune system. It is obvious that immunotherapy is emerging as a major therapeutic modality in chronic lymphocytic leukemia. Dr. Kipps addresses the present understanding of the immune status of CLL and the role of passive immunotherapy with monoclonal antibodies such as rituximab, alemtuzumab, and emerging new antibodies. In addition the interaction between the CLL cells and the immune system, which has been exploited in gene therapy with transfection of CLL cells by CD40 ligand, is discussed. In Section III, Dr. Michael Keating examines the question "Do we have the tools to cure CLL?" and focuses on the fact that we now have three distinct modalities, which are able to achieve high quality remissions with polymerase chain reaction (PCR) negativity for the immunoglobulin heavy chain in CLL. These modalities include initial chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab, the use of alemtuzumab for marrow cytoreduction in minimal residual disease and allogeneic bone marrow transplants. The emergence of non-ablative marrow transplants in CLL has led to the broadening of the range of opportunities to treat older patients. The addition of rituximab to the chemotherapy preparative regimens appears to be a significant advance. The combination of our increased understanding of the biology, immune status, and therapy of CLL provides for the first time the opportunity for curative strategies.

B-chronic lymphocytic leukemia: practical aspects

B-CLL is the most common adult leukemia in the Western world. It is a neoplasia of mature looking B-monoclonal lymphocytes co-expressing the CD5 antigen (involving the blood, the bone marrow, the lymph nodes and related organs). Much new information about the nature of the neoplastic cells, including chromosomal and molecular changes as well as mechanisms participating in the survival of the leukemic clone have been published recently, in an attempt to elucidate the biology of the disease and identify prognostic subgroups. For the time being, clinical stage based on Rai and Binet staging systems remains the strongest predictor of prognosis and patients' survival, and therefore it affects treatment decisions. In the early stages treatment may be delayed until progression. When treatment is necessary according to well-established criteria, there are nowadays many different options. Chlorambucil has been the standard regimen for many years. During the last decade novel modalities have been tried with the emphasis on fludarabine and 2-chlorodeoxyadenosine and their combinations with other drugs. Such an approach offers greater probability of a durable complete remission but no effect on overall survival has been clearly proven so far. Other modalities, included in the therapeutic armamentarium, are monoclonal antibodies, stem cell transplantation (autologous or allogeneic) and new experimental drugs. Supportive care is an important part of patient management and it involves restoring hypogammaglobulinemia and disease-related anemia by polyvalent immunoglobulin administration and erythropoietin respectively.

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.

Chronic lymphocytic leukemia

Historically, treatment of chronic lymphocytic leukemia (CLL) essentially had been palliative. During the past two decades, effective new therapies for the treatment of CLL have emerged. The advent of fludarabine, a purine analog with activity against chlorambucil-resistant CLL, showed promising results with high response rates in previously untreated patients. These improvements in response and delays in disease progression have not translated into a survival benefit, indicating that chlorambucil may be the preferred first-line therapy when treatment is indicated. Allogeneic hematopoietic stem cell transplantation, by combining the cytoreductive effects of conditioning with a potent graft-versus-tumor effect, is the only treatment modality with the prospect of cure for patients with CLL. However, conventional hematopoietic stem cell transplantation can be offered only to select patients with CLL because of older age and comorbid conditions. Novel methods of transplantation exploiting the graft-versus-leukemia effect while reducing the toxicity of the pretransplant conditioning are promising approaches that may enable more patients to benefit from this therapy. Monoclonal antibodies such as rituximab or alemtuzumab (Campath-1H; llex Pharmaceuticals, San Antonio, TX) are agents with activity in untreated and resistant CLL. Efforts are being focused on combining these monoclonal antibodies with chemotherapy and the development of rationally designed drugs.

A phase II study of sequential combination chemotherapy with cyclophosphamide, prednisone, and 2-chlorodeoxyadenosine in previously untreated patients with chronic lymphocytic leukemia

In an earlier study of previously untreated patients with chronic lymphocytic leukemia (CLL), we used a concomitant combination of chlorambucil and 2-chlorodeoxyadenosine and reported overall (OR) and complete (CR) remission rates of 80% and 20%, respectively. After a median follow-up of 5 years, more than 80% of the responders have had a relapse. In the current phase II study of 27 previously untreated patients with CLL, we used a sequential combination of six cycles of intravenous cyclophosphamide (1 g/m2) plus oral prednisone (100 mg/m2 per day for 5 days) followed by two to six cycles of 2-chlorodeoxyadenosine (5 mg/m2 per day for 5 days). The OR and CR rates were 96% and 33%, respectively. After a median follow-up of 29 months, 35% of the responders have had a relapse. Progression-free survival was significantly better in CR patients than in those with partial remission. However, minimal residual disease was phenotypically detected in four of the nine CR patients. Despite the fact that the current OR and CR rates are superior to those seen in a historical cohort treated with a concomitant schedule, a longer follow-up period is needed to assess the durability of these remissions, and a controlled trial is necessary to estimate the impact on overall survival and toxicity.