Early treatment of high-risk chronic lymphocytic leukemia with alemtuzumab and rituximab

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) usually are treated only for progressive disease. However, the discovery of biologic predictors of a high risk of disease progression, together with the development of newer, more targeted therapies, could change this paradigm. In this phase 2 study, the authors tested the safety and efficacy of early treatment for patients with high-risk CLL using alemtuzumab and rituximab. METHODS: Patients were eligible for treatment if they were 1) previously untreated, 2) had no National Cancer Institute-Working Group 1996 criteria for treatment, and 3) had at least 1 marker of high-risk disease 17p13-, 11q22-, or a combination of unmutated IgVH and CD38+/ZAP70+). Treatment consisted of subcutaneous alemtuzumab (initial dose escalation followed by 30 mg on Monday, Wednesday, and Friday for 4 weeks) and intravenous rituximab (375 mg/m(2) per week x4 doses). All patients received Pneumocystis pneumonia and herpes virus prophylaxis and were monitored for cytomegalovirus reactivation. RESULTS: Twenty-seven of 30 patients (90%) responded to therapy with 11 (37%) complete responses (CRs). Five patients (17%) patients who had a CR had no detectable minimal residual disease. The median response duration was 14.4 months, and only 9 patients required retreatment for progressive disease at the time of the current report (median follow-up, 17.6 months). Study patients had a significantly longer time from diagnosis to first treatment for CLL according to conventional indications than a comparison cohort with similar biologic risk profiles. CONCLUSIONS: The therapy regimen used was safe and effective for early treatment of patients with high-risk CLL. Further studies will be required to determine whether this early treatment strategy decreases morbidity and mortality for high-risk CLL.     

Eradication of minimal residual disease with alemtuzumab in B-cell chronic lymphocytic leukemia (B-CLL) patients: the need for a standard method of detection and the potential impact of bone marrow clearance on disease outcome

The introduction of new therapeutic agents, such as fludarabine phosphate (Fludara) and alemtuzumab (MabCampath, Campath), has made it possible to treat B-cell chronic lymphocytic leukemia (B-CLL) more effectively, compared with alkylating agents. However, although an increasing number of patients are able to achieve complete remission (CR), relapse is almost inevitable, because of the re-emergence of the malignant clone from small numbers of residual malignant cells. This phenomenon has introduced a need for a more sensitive assessment of low-level disease which, in turn, has encouraged the development of therapies aimed at the eradication of all residual disease in CR patients. The eradication of residual disease is associated with improved remission durability and has great potential in offering the possibility of cure. Alemtuzumab is the foundation of many eradication-based treatment approaches because of its ability to achieve clinical remissions and to successfully purge minimal residual disease (MRD) from both blood and bone marrow in B-CLL patients. This article describes and compares polymerase chain reaction (PCR) and flow cytometric methodologies for the assessment of MRD, and presents data demonstrating that alemtuzumab can eliminate residual malignant cells from blood and bone marrow (whether assessed by PCR or flow cytometry) at the highest levels of sensitivity currently available. The ability to clear MRD from bone marrow in patients achieving clinical CR using alemtuzumab is a significant step forward in the treatment of B-CLL, and supports treatment strategies in which alemtuzumab is used in combination with other agents. Purging of MRD from both blood and bone marrow also enables patients to proceed to autologous hematopoietic stem cell transplantation, a strategy that is able to achieve long-term remission.     

Treatment of fludarabine‐refractory chronic lymphocytic leukemia

The development of resistance to purine analogs defines a poor‐risk subset of patients with chronic lymphocytic leukemia (CLL). Although in recent years chemoimmunotherapeutic combinations such as fludarabine, cyclophosphamide, and rituximab have induced response rates of 95% in previously untreated patients and increased the rates of failure‐free survival, CLL remains incurable for many patients because of a lack of disease response or the development of refractoriness to fludarabine. Fludarabine‐refractory disease is defined as CLL that does not respond to fludarabine or that recurs within 6 months of treatment with a fludarabine‐containing regimen. The natural course of the disease is associated with poor survival. Salvage therapeutic strategies include alemtuzumab‐containing regimens, targeted agents, and allogeneic stem cell transplantation. Single‐agent alemtuzumab induces response in up to 40% of patients with fludarabine‐refractory CLL, but responses are not durable, and the median survival is approximately 1 to 2 years. Alemtuzumab is also combined with fludarabine, cyclophosphamide, and/or rituximab, and other agents such as lenalidomide and flavopiridol, as well as targeted agents, and used in fludarabine‐refractory CLL. Cumulative evidence suggests that allogeneic stem cell transplantation is an efficacious therapeutic strategy for patients who do not respond to fludarabine or who develop disease recurrence within 12 months after purine analog treatment. In conclusion, chemoimmunotherapy regimens that include alemtuzumab and/or rituximab and allogeneic stem cell transplantation improve the prognosis of this disease, but there is a continued need for novel, more effective therapies. Cancer 2009. © 2009 American Cancer Society.     

Role of immunochemotherapy in the treatment of chronic lymphocytic leukemia

Major advances have been made in our understanding of the biology and opportunities for treatment of chronic lymphocytic leukemia in recent times. Newer treatment regimens incorporating purine nucleoside analogs have increased the rate of successful remission induction in chronic lymphocytic leukemia patients. Moreover, recent combination chemoimmunotherapy regimens have produced more frequent complete molecular remissions, and early evidence seems to suggest that this could result in prolonged duration of responses, although this association remains to be clearly demonstrated. This review will summarize recent advances in the biology and the management of chronic lymphocytic leukemia, including prognostic factors, pointing mainly on combination chemotherapy based on nucleoside analogs and monoclonal antibodies. In our opinion, in the future a significant improvement of clinical benefits in chronic lymphocytic leukemia will be obtained through the administration of cocktails of monoclonal antibodies combined with chemotherapy in different modalities.     

Combination therapy with fludarabine and rituximab followed by alemtuzumab in the first-line treatment of patients with chronic lymphocytic leukemia or small lymphocytic lymphoma: a phase 2 trial of the Minnie Pearl Cancer Research Network

BACKGROUND: The purpose of the current study was to evaluate the efficacy and toxicity of the combination of fludarabine and rituximab, followed by alemtuzumab, as first-line treatment for patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). METHODS: In a nonrandomized phase 2 trial, 41 patients who had previously untreated CLL or SLL and required treatment received 4 cycles of the fludarabine and rituximab combination followed 5 weeks later by 4 weeks (12 doses) of intravenous alemtuzumab therapy. The response to treatment was evaluated after completion of treatment with fludarabine and rituximab, and again after the completion of alemtuzumab consolidation. RESULTS: Initial treatment with the combination of fludarabine and rituximab was well tolerated, and produced a 71% overall response rate (13% complete response). Thirty-four patients began treatment with intravenous alemtuzumab, but this drug was relatively poorly tolerated when given at a short interval after fludarabine and rituximab, and only 20 patients (49% of total) were able to complete the prescribed course. Five patients had an improvement in their response with alemtuzumab; the final complete response rate was 21%. The median progression-free survival for the entire group was 42 months. Toxicity with alemtuzumab included infusion-related toxicity, myelosuppression, and opportunistic infections. CONCLUSIONS: The intravenous schedule of alemtuzumab employed in the trial was relatively poorly tolerated in this community-based trial. The relatively low complete response rates after treatment with the combination of fludarabine and rituximab and after the completion of treatment suggest that these abbreviated courses may compromise efficacy. The generalized use of alemtuzumab as consolidation therapy cannot yet be recommended for community practice. However, optimization of the route of administration, duration of treatment, and interval after completion of induction therapy may improve efficacy, and further investigation is ongoing.     

Fatal adenovirus infection during alemtuzumab (anti-CD52 monoclonal antibody) treatment of a patient with fludarabine-refractory B-cell chronic lymphocytic leukemia

Alemtuzumab (Campath-1H) is a humanized CD52 monoclonal antibody that targets normal as well as malignant B- and T-lymphocytes. Alemtuzumab has significant antitumor activity in chronic lymphocytic leukemia (B-CLL) but also induces immunosuppression. We describe a case of fatal adenovirus infection in a heavily pretreated patient with fludarabine-refractory B-CLL receiving alemtuzumab therapy, drawing attention to the fact that also viruses other than cytomegalovirus (CMV) and herpes simplex (HSV) need to be considered in B-CLL patients with fever of unknown origin while on alemtuzumab treatment.     

Measurable residual disease in the treatment of chronic lymphocytic leukemia

Treatment outcomes of chronic lymphocytic leukemia (CLL) have improved since chemoimmunotherapy and novel drugs became available for CLL treatment; therefore, more sensitive methods to evaluate residual CLL cells in patients are required. Measurable residual disease (MRD) has been assessed in several clinical trials on CLL using flow cytometry, real-time quantitative PCR (RQ-PCR) with allele-specific oligonucleotide (ASO) primers, and high-throughput sequencing. MRD assessment is useful to predict the treatment outcomes in the context of chemotherapy and treatment with novel drugs such as venetoclax. In this review, we discuss major techniques for MRD assessment, data from relevant clinical trials, and the future of MRD assessment in CLL treatment.     

Hematopoietic stem cell transplantation in chronic lymphocytic leukemia: A report of 12 patients from a single institution

Background: Stem-cell transplantation is a reasonable therapeutic approach for younger patients with high-risk CLL.Patients and methods: Twelve patients (seven males; median age 47 years, range 29–51) with high-risk CLL underwent transplantation (allo, n = 7; auto, n = 5). The conditioning regimen consisted of cyclophosphamide and total body irradiation in 11 patients, and BEAC in the remaining one. Minimal residual disease (MRD) was assessed by cytofluorometry and PCR.Results: All 11 evaluable patients engrafted. Of the seven allografted patients, two died of treatment-related causes; three patients developed acute GVHD. No transplant-related mortality was observed in autografted patients. After transplantation, 10 of 11 patients evaluable for response achieved CR (91%; 95% CI 59%–100%) which was molecular in nine patients (82%; 95% CI 48%–98%). One patient in CR but MRD+ relapsed nine months after transplantation and died. Seven patients remain in molecular CR for a median of 16 months (range 1–58). Estimated actuarial survival and disease-free survival at two years is 81% (95% CI 43%–100%) and 71% (95% CI 43%–99%), respectively. Relapse risk at two years is 12.5% (95% CI 0%–35.5%).Conclusions: Patients with high-risk CLL can achieve long-lasting molecular CR after SCT. The role of transplants in CLL management deserves investigation in controlled trials.     

Monoclonal antibodies in chronic lymphocytic leukemia

Multiple options are now available for the treatment of chronic lymphocytic leukemia. Over the last 10 years, monoclonal antibodies have become an integral part of the management of this disease. Alemtuzumab has received approval for use in patients with fludarabine-refractory chronic lymphocytic leukemia. Rituximab has been investigated extensively in chronic lymphocytic leukemia both as a single agent and in combination with chemotherapy and other monoclonal antibodies. Epratuzumab and lumiliximab are newer monoclonal antibodies in the early phase of clinical development. This article will review the monoclonal antibodies more commonly used to treat chronic lymphocytic leukemia, the results obtained with monoclonal antibodies as single agents and in combination with chemotherapy, and other biological agents and newer compounds undergoing clinical trials.     

An observational study of once weekly intravenous ganciclovir as CMV prophylaxis in heavily pre-treated chronic lymphocytic leukemia patients receiving subcutaneous alemtuzumab

Fifteen consecutive resistant/relapsed chronic lymphocytic leukemia (CLL) patients (median age: 65 years) received alemtuzumab for 16 consecutive weeks. All patients had negative CMV anti genemia at baseline. Five patients received oral acyclovir 800 mg twice a day for CMV prophylaxis and 10 patients got intravenous (iv) ganciclovir 7.5 mg/kg once a week. A total of five CMV reactivations occurred, four in the acyclovir and one in the ganciclovir prophylaxis group. Alemtuzumab was then discontinued and all patients were treated with iv ganciclovir 7.5 mg/kg per day. All patients achieved negative CMV anti genemia after a median of 15 days of therapy. Weekly iv ganciclovir prophylaxis and alemtuzumab treatment were then restarted without any further CMV reactivations. In conclusion, weekly iv ganciclovir appears feasible and effective in preventing CMV reactivation and disease in this setting of high-risk immunocompromised patients, allowing an easier management of a therapy otherwise difficult to be routinely used.     

HLA antigens in iranian patients with B-cell chronic lymphocytic leukemia

The frequency of HLA class-I and class-II antigens was investigated in 32 Iranian patients with B-cell chronic lymphocytic leukemia (B-CLL), using the microlymphocytotoxicity method. A significant increase in the HLA-B13 (P<0.01) and DR53 (P < 0.05) and a significant negative association with the A11 (P < 0.05), B35 (P < 0. 05), Cw3 (P < 0.05), and DR1 (P < 0.02) antigens were observed in these patients, compared to the control normal population. These results suggest involvement of some HLA antigens in the multifactorial process of predisposition to B-CLL.     

Prognostic implication of early minimal residual disease evaluation in patients with chronic myelomonocytic leukemia

To investigate the prognostic implication of minimal residual disease (MRD) evaluation in chronic myelomonocytic leukemia (CMML), we conducted a restropective study included a total of 174 CMML patients in our hospital from January 2010 to March 2021. In which 50/174 (29%) bone marrow samples were conducted by multiparameter flow cytometry (FCM) assessed MRD analysis after the first three cycles of treatment and were included in this study. MRD was detected by six- to eight-colour FCM. The achievement of early MRD negativity had better clinical outcomes in patients with CMML, which fared better prognosis in terms of not only PFS (P=0.006) but also OS (P=0.02) after the first cycle, and PFS (P=0.023 and P=0.041) after the second and third cycles, whereas no significantly influence in OS. In addition, MRD negative after initial treatment remained its independent prognostic value associated with PFS (adjusted hazard ratio [HR] 0.161, 95 CI 0.035-0.738; P=0.019) and OS (adjusted HR 0.136; 95 CI 0.017-1.077; P=0.059), indicating that patients with MRD-negative after the initial treatment alone could obtain the greatest clinical benefit. According to MRD level, the patients were divided into 4 different groups: very low risk (fewer than 10^-4 cells) in 15 cases, low risk (10^-4 to 10^-3 cells) in 6; and 6 were at intermediate risk (fewer than 10^-3 to 10^-2 cells). The rest of 23 patients were were assigned to the high-risk grades (more than 10^-2 residual cells), we find this risk stratification model is significantly associated with better PFS (P=0.002) but marginal significantly associated with OS (P=0.068). Notably, patients with DNMT3A mutation fared a shorter PFS in the MRD positive subgroup (P=0.068). MRD is highly predictive of prognosis, and its combination with molecular profile may help identify patients at increased risk for progression to further improve the management of patients with CMML. Large-scaled investigations are warranted to validate our conclusions and its potential in clinical practice.     

CAMPATH (alemtuzumab) for the treatment of chronic lymphocytic leukemia and beyond

CAMPATH^® (CAMPATH-1H, alemtuzumab, MabCAMPATH), is a lymphocyte-depleting humanized monoclonal antibody that was recently approved in the USA and Europe for the treatment of chronic lymphocytic leukemia (CLL). It targets CD52 – a small glycosylphosphatidylinositol-anchored glycoprotein that is highly expressed on normal T- and B-lymphocytes and on a large proportion of lymphoid cell malignancies – but not on hematopoietic progenitor cells. CAMPATH was shown to be effective against CLL refractory to chemotherapy with an acceptable toxicity profile. CAMPATH is also active against T-cell prolymphocytic leukemia and has been extensively used to prevent graft-versus-host disease associated with bone marrow transplantation. CAMPATH is owned by ILEX Pharmaceuticals LP and distributed by Schering AG and its US affiliate Berlex Laboratories.     

Efficacy of phosphatidylinositol‐3 kinase inhibitors with diverse isoform selectivity profiles for inhibiting the survival of chronic lymphocytic leukemia cells

Pharmacological inhibition of phosphatiylinositide‐3‐kinase (PI3K)‐mediated signaling holds great promise for treating chronic lymphocytic leukemia (CLL). Therefore we assessed three structurally related PI3K inhibitors targeting the PI3K‐δ isoform for their ability to inhibit the survival of freshly isolated CLL cells. The purely PI3K‐δ‐selective inhibitor idelalisib was compared to copanlisib (BAY 80‐6946) and duvelisib (IPI‐145), with isoform target profiles that additionally include PI3K‐α or PI3K‐γ, respectively. The concentrations leading to half‐maximal reduction of the survival of CLL cells were more than ten‐fold lower for copanlisib than for idelalisib and duvelisib. At concentrations reflecting the biological availability of the different inhibitors, high levels of apoptotic response among CLL samples were attained more consistently with copanlisib than with idelalisib. Copanlisib selectively reduced the survival of CLL cells compared to T cells and to B cells from healthy donors. In addition copanlisib and duvelisib impaired the migration of CLL cells towards CXCL12 to a greater extent than equimolar idelalisib. Similarly copanlisib and duvelisib reduced the survival of CLL cells in co‐cultures with the bone marrow stroma cell line HS‐5 more strongly than idelalisib. Survival inhibition by copanlisib and idelalisib was enhanced by the monoclonal CD20 antibodies rituximab and obinutuzumab (GA101), while antibody‐dependent cellular cytotoxicity mediated by alemtuzumab and peripheral blood mononuclear cells was not substantially impaired by both PI3K inhibitors for the CLL‐derived JVM‐3 cell line as target cells. Taken together, targeting the α‐ and δ‐ p110 isoforms with copanlisib may be a useful strategy for the treatment of CLL and warrants further clinical investigation.     

Monoclonal antibodies in the treatment of chronic lymphocytic leukemia

Traditional therapy for chronic lymphocytic leukemia (CLL) has consisted of alkylating agents, purine analogs, or a combination of these drugs. These agents are effective at producing remissions but are not curative. Thus, new drugs are still needed to improve the outcome of patients with CLL. The introduction of monoclonal antibodies, such as rituximab and alemtuzumab, provides a novel therapeutic modality. Rituximab is an active agent in CLL. Standard doses of rituximab result in higher response rates in previously untreated than in relapsed patients but low complete response (CR) rates. Rituximab is most effective in combination with chemotherapy, especially fludarabine-based regimens in the first-line and salvage setting. Rituximab is also useful in the treatment of complications of CLL, such as pure red cell aplasia, autoimmune thrombocytopenia, and autoimmune hemolytic anemia. Alemtuzumab has impressive activity in patients with refractory CLL and may play an important role in the consolidation treatment of CLL. Alemtuzumab is most efficacious at clearing disease in the peripheral blood and bone marrow. Bulky lymphadenopathy is less sensitive to therapy. Because of the significant lymphopenia associated with alemtuzumab, antibacterial and antiviral prophylaxis should always be used.     

Glucocorticoid receptors in chronic lymphocytic leukemia

Glucocorticoid receptor (GR) levels have not been extensively studied in untreated patients with chronic lymphocytic leukemia (CLL). We have measured tumor GR levels using a whole cell assay in 18 untreated patients with CLL and correlated these levels with various in-vitro and in-vivo data. In 12 of these patients, tumor cells from more than one tissue were simultaneously studied. Measurable GR levels were found in all 36 specimens studied with median total GR levels in blood, bone marrow, and lymph nodes being 3018 (n = 17), 3524 (n = 12) and 3102 (n = 7) sites/cell respectively. GR levels did not correlate with in-vitro sensitivity, as measured by inhibition by dexamethasone of radiolabelled leucine, uridine, and thymidine uptake, nor with the clinical or laboratory features examined. Nine patients were treated with dexamethasone as a single agent; blood GR levels were not predictive of antitumor response. We conclude that in patients with CLL, malignant cells from all involved tissues have measurable numbers of GRs, but these are not correlated with in-vitro sensitivity to glucocorticoid. Blood GR levels do not correlate with antitumor response; further studies are required to see if bone marrow or lymph node receptor levels correlate with antitumor response to steroids.     

Bepridil exhibits anti‐leukemic activity associated with NOTCH1 pathway inhibition in chronic lymphocytic leukemia

Dysregulated NOTCH1 signaling, by either gene mutations or microenvironment interactions, has been increasingly linked to chronic lymphocytic leukemia (CLL). Thus, inhibiting NOTCH1 activity represents a potential therapeutic opportunity for this disease. Using gene expression‐based screening, we identified the calcium channel modulator bepridil as a new NOTCH1 pathway inhibitor. In primary CLL cells, bepridil induced selective apoptosis even in the presence of the protective stroma. Cytotoxic effects of bepridil were independent of NOTCH1 mutation and other prognostic markers. The antitumor efficacy of bepridil was associated with inhibition of NOTCH1 activity through a decrement in trans‐membrane and activated NOTCH1 protein levels with unchanged NOTCH2 protein levels. In a CLL xenotransplant model, bepridil significantly reduced the percentage of leukemic cells infiltrating the spleen via enhanced apoptosis and decreased NOTCH1 activation. In conclusion, we report in vitro and in vivo anti‐leukemic activity of bepridil associated with inhibition of the NOTCH1 pathway in CLL. These data provide a rationale for the clinical development of bepridil as anti‐NOTCH1 targeted therapy for CLL patients.     

The VEGF receptor,neuropilin‐1, represents a promising novel target for chronic lymphocytic leukemia patients

Angiogenesis has been shown to substantially contribute to the progression of chronic lymphocytic leukemia (CLL). Neuropilin‐1 (NRP1) represents a receptor for vascular endothelial growth factor (VEGF), which has been reported to be overexpressed in several malignancies. In our study, we characterized mRNA levels of VEGF receptors including NRP1 in a large cohort of CLL patients (n = 114), additionally we performed a detailed characterization of NRP1 expression on B cells, plasmacytoid dendritic cells (PDCs) and regulatory T cells (Tregs). The expression of NRP1 was significantly higher on leukemic lymphocytes compared to control B lymphocytes on mRNA and protein levels (22.72% vs. 0.2%, p = 0.0003, respectively), Tregs (42.6% vs. 16.05%, p = 0.0003) and PDCs (100% vs. 98% p < 0.0001). In functional studies, we found higher NRP1 expression on CLL cells after stimulation with VEGF. The correlation between expression of VEGF receptors: FLT1, NRP1 and FOXP3 expression (r² = 0.53, p < 0.0001 and r² = 0.49, p < 0.0001, respectively) was observed. Earlier we described the specific Treg reduction during the therapy with thalidomide in vivo. Now we observe the reduction of the NRP1 expression on Tregs in vitro, thereby suggesting a possible target of thalidomide action. In conclusion, NRP1 might represent an interesting link between angiogenesis and tolerance mechanisms and represents interesting target for therapy.     

The impacts of zanubrutinib on immune cells in patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

Ibrutinib, a first‐generation Bruton's tyrosine kinase (BTK) inhibitor, could improve immunity of relapsed or refractory (R/R) chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) patients. Whether zanubrutinib, a second‐generation selective BTK inhibitor, has similar effects as ibrutinib remains to be determined. Dynamics of number and immunophenotype of immune cells during zanubrutinib treatment in 25 R/R CLL/SLL patients were examined by flow cytometry and blood routine tests. The expression intensity of programmed death‐1 (PD‐1) on total CD4⁺ (P < .01), total CD8⁺ (P < .01), and T helper cells (P < .05) and cytotoxic T lymphocyte‐associated antigen‐4 (CTLA‐4) on total CD4⁺ (P = .010) and regulatory T cells (P < .05) reduced after treatment. There were significant differences in expression intensity of CD19 (P < .01), C‐X‐C chemokine receptor type 5 (CXCR5) (P < .01), and CD49d (P < .05) on B cells before and after treatment. Downregulation of PD‐1 on T cells and CXCR5 and CD19 on B cells were observed in nearly all patients after zanubrutinib treatment. Programmed death‐ligand 1 expression downregulated, especially in the female, CLL, normal spleen, normal β2‐macroglobulin (β2‐MG) and abnormal lactate dehydrogenase (LDH) subgroups, and CTLA‐4 expression on CD4+ T cells tended to decrease in the male, old, CLL, splenomegaly, abnormal β2‐MG, normal LDH, IGHV‐mutated and wild‐type tumor protein 53 subgroups after zanubrutinib treatment. These findings suggest that zanubrutinib can regulate immunity primarily by improving T cell exhaustion, inhibiting suppressor cells and disrupting CLL cells migration through downregulation of adhesion/homing receptors. Furthermore, favorable changes in cell number and immunophenotype were preferably observed in patients without adverse prognostic factors.