Allogeneic Transplant with Reduced Intensity Conditioning Regimens may Overcome the Poor Prognosis of B-Cell Chronic Lymphocytic Leukemia with Unmutated Immunoglobulin Variable Heavy-Chain Gene and Chromosomal Abnormalities (11q− and 17p−)

Relapsed/refractory CLL: the role of allo-SCT, CAR-T, and T-cell engagers

Chronic lymphocytic leukemia (CLL) patients who are refractory to both Bruton's tyrosine kinase and B-cell/CLL lymphoma 2 (BCL2) inhibitors face a significant treatment challenge, with limited and short-lasting disease control options. This underscores the urgent need for novel therapeutic strategies. Immunotherapy has emerged as a promising approach to address this unmet need, offering the potential for durable remissions and improved patient outcomes. Historically, allogeneic stem cell transplantation has been used for high-risk CLL patients, demonstrating promising survival rates. However, its applicability is limited by high treatment-related mortality and chronic graft-versus-host disease, especially in older and frail patients. Chimeric antigen receptor (CAR) T-cell therapy is gaining attention for its potential in relapsed/refractory CLL. Early clinical trials have shown that CAR T cells can induce durable remissions, with encouraging overall response rates in heavily pretreated patients. Additionally, bispecific antibodies are being explored as immunotherapeutic strategies, showing promising preclinical and early clinical results in targeting CLL cells effectively. One of the major challenges in CLL treatment with T-cell-based therapies is the acquired T-cell dysfunction observed in patients. To overcome these limitations, strategies such as combining targeted agents with cellular immunotherapies, modifying CAR designs, and incorporating immunomodulatory compounds into the manufacturing process are being investigated. These innovative approaches aim to enhance T-cell engagement and improve outcomes for CLL patients, offering hope for more effective and sustainable treatments in the future.

The role of allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia: A review

Although the use of allogeneic hematopoietic cell transplantation (HCT) for chronic lymphocytic leukemia (CLL) has declined with the development of novel targeted agents, it continues to play an important role for eligible patients with high-risk or heavily pretreated CLL who lack other treatment options. CLL is susceptible to a potent graft-versus-leukemia (GVL) effect which produces long-lasting remissions in 30-50% of transplanted patients. While allogeneic HCT is associated with significant risks of graft-versus-host disease (GVHD), infection, and non-relapse mortality (NRM), improvements in patient and donor selection, reduced intensity conditioning (RIC), GVHD prophylaxis, and supportive care have rendered this an increasingly safe and effective procedure in the current era. In this review, we discuss recent advances in allogeneic HCT for CLL, with a focus on the optimal evidence-based strategies to maximize benefit and minimize toxicity of this potentially curative cellular therapy.

A novel event-free survival endpoint in locally advanced pancreatic cancer

The treatment paradigm for locally advanced pancreatic cancer (LAPC) is evolving rapidly. The development of neoadjuvant therapies composed of combination therapies and the evaluation of their impact on conversion to borderline resectable (BR) status, resection, and ultimately overall survival (OS) are presently being pursued. These efforts justify re-visiting study endpoints in order to better predict therapeutic effects on OS, by capturing not only the achievement of R0 resection at the end of induction therapy but also the long-term reductions in the rate of local and distal recurrence. The proposed herein event-free survival (EFS) endpoint, with its novel definition specific to LAPC, is formulated to achieve these objectives. It is an analog to disease-free survival (DFS) endpoint in the adjuvant setting applied to the neoadjuvant setting and may be a valuable surrogate endpoint for this patient population.

Outcomes of patients diagnosed with chronic lymphocytic leukemia after allogeneic hematopoietic stem cell transplantation: Results from a tertiary care center

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HCT) is currently the only curative treatment for patients with chronic lymphocytic leukemia (CLL).

METHODS

We analyzed the outcomes of 93 patients (median age: 52 years) who underwent allo-HCT at our center between 1989 and 2019.

RESULTS

After a median follow-up of 35 months, relapse was observed in 15.1% (n = 14) patients. The estimated 2-year non-relapse mortality, relapse-free survival, and overall survival (OS) were 38.1%, 54.2%, and 58.7%, respectively. The ECOG performance status ≥ 2 (hazard ratio [HR]: 4.1; p = .001) and use of total body irradiation (in a myeloablative conditioning regimen; HR: 2.64; p = .005) were predictive of poor OS after multivariable analysis. The occurrence of sinusoidal obstruction syndrome/veno-occlusive disease post-transplant was associated with poor survival (p = .001).

CONCLUSION

Although the use of kinase and bcl2 inhibitors may result in a decrease in the number and need of transplants, allo-HCT remains a viable option in selected patients with high-risk CLL and good performance status.

Minimal residual disease in chronic lymphocytic leukemia: A consensus paper that presents the clinical impact of the presently available laboratory approaches

Chronic lymphocytic leukemia (CLL) is a malignancy defined by the accumulation of mature lymphocytes in the lymphoid tissues, bone marrow, and blood. Therapy for CLL is guided according to the Rai and Binet staging systems. Nevertheless, state-of-the-art protocols in disease monitoring, diagnostics, and prognostics for CLL are based on the assessment of minimal residual disease (MRD). MRD is internationally considered to be the level of disease that can be detected by sensitive techniques and represents incomplete treatment and a probability of disease relapse. MRD detection has been continuously improved by the quick development of both flow cytometry and molecular biology technology, as well as by next-generation sequencing. Considering that MRD detection is moving more and more from research to clinical practice, where it can be an independent prognostic marker, in this paper, we present the methodologies by which MRD is evaluated, from translational research to clinical practice.

Reduced intensity is preferred over myeloablative conditioning allogeneic HCT in chronic lymphocytic leukemia whenever indicated: A systematic review/meta-analysis

Despite availability of new and more effective therapies for chronic lymphocytic leukemia, presently this disease remains incurable unless eligible patients are offered an allogeneic hematopoietic cell transplant. Recent published clinical practice recommendations on behalf of the American Society for Blood and Marrow Transplantation relegated the role of for allogeneic hematopoietic cell transplantation to later stages of the disease. To our knowledge, no randomized controlled trial has been performed to date comparing myeloablative versus reduced intensity conditioning regimens in chronic lymphocytic leukemia patients eligible for the procedure. We performed a systematic review/meta-analysis to assess the efficacy of allogeneic hematopoietic cell transplantation when using myeloablative or reduced intensity conditioning regimens. We report the results in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Based on lower non-relapse mortality and slightly better overall survival rates, reduced intensity conditioning regimens appear to be the most desirable choice whenever the procedure is indicated for this disease. It appears highly unlikely that a RCT will be ever performed comparing reduced intensity vs. myeloablative allogeneic hematopoietic cell transplantation in chronic lymphocytic leukemia. In the absence of such a study, results of this systematic review/meta-analysis represent the best available evidence supporting this recommendation whenever indicated in patients with chronic lymphocytic leukemia.

Using prognostic models in CLL to personalize approach to clinical care: Are we there yet?

Four decades ago, two staging systems were developed to help stratify CLL into different prognostic categories. These systems, the Rai and the Binet staging, depended entirely on abnormal exam findings and evidence of anemia and thrombocytopenia. Better understanding of biologic, genetic, and molecular characteristics of CLL have contributed to better appreciating its clinical heterogeneity. New prognostic models, the GCLLSG prognostic index and the CLL-IPI, emerged. They incorporate biologic and genetic information related to CLL and are capable of predicting survival outcomes and cases anticipated to need therapy earlier in the disease course. Accordingly, these newer models are helping develop better informed surveillance strategies and ultimately tailor treatment intensity according to presence (or lack thereof) of certain prognostic markers. This represents a step towards personalizing care of CLL patients. We anticipate that as more prognostic factors continue to be identified, the GCLLSG prognostic index and CLL-IPI models will undergo further revisions.

Flow cytometry minimal residual disease after allogeneic transplant for chronic lymphocytic leukemia

OBJECTIVES

This study investigates whether achieving complete remission (CR) with undetectable minimal residual disease (MRD) after allogeneic stem cell transplantation (allo-SCT) for chronic lymphocytic leukemia (CLL) affects outcome.

METHODS

We retrospectively studied 46 patients transplanted for CLL and evaluated for post-transplant MRD by flow cytometry.

RESULTS

At transplant time, 43% of the patients were in CR, including one with undetectable MRD, 46% were in partial response, and 11% had refractory disease. After transplant, 61% of the patients achieved CR with undetectable MRD status. By multivariate analysis, reaching CR with undetectable MRD 12 months after transplant was the only factor associated with better progression-free survival (P = 0.02) and attaining undetectable MRD, independently of the time of negativity, was the only factor that correlated with better overall survival (P = 0.04).

CONCLUSION

Thus, achieving undetectable MRD status after allo-SCT for CLL is a major goal to improve post-transplant outcome.

Hematopoietic Cell Transplantation for Richter Syndrome

Treatment combining chemotherapy with immunotherapy as well as novel targeted therapies have shown limited efficacy in Richter syndrome. Overall response rates after chemoimmunotherapy range from 43% to 67%, but remissions are generally short-lived. In chronic lymphocytic leukemia (CLL), allogeneic hematopoietic cell transplantation (all-HCT) is considered a potentially curative treatment modality, yielding 3-year overall survival rates exceeding 50% and a plateau in survival curves. In Richter syndrome, efficacy of allo-HCT depends on demonstrating an objective response (complete remission or partial response) before allografting, with resulting 3-year survival rates of 41% to 75%. On the other hand, the efficacy of autologous HCT is limited, especially when considering that patients autografted for Richter syndrome might relapse with CLL in 35% of cases. Notwithstanding the scarcity of published data, we recommend that patients with Richter syndrome should be referred to transplant centers as soon as the diagnosis is confirmed to evaluate their candidacy for allo-HCT. Establishing a clonal relationship to CLL is important considering the more aggressive disease course in clonally related Richter syndrome. Moreover, achievement of a complete remission or partial response to salvage therapy must be a prerequisite before moving forward with allografting for Richter syndrome. Patients who fail to demonstrate an objective response to salvage therapy should be considered for enrollment in clinical trials.

A drive through cellular therapy for CLL in 2015: allogeneic cell transplantation and CARs

Over the past decade the development of safer reduced-intensity conditioning regimens, expanded donor pools, advances in supportive care, and prevention/management of graft-versus-host disease have expanded stem cell transplantation (SCT) availability for chronic lymphocytic leukemia (CLL) patients. However, there are now increasingly active treatment options available for CLL patients with favorable toxicity profiles and convenient administration schedules. This raises the critical issue of whether or not attainment of cure remains a necessary goal. It is now less clear that treatment with curative intention and with significant toxicity is required for long-term survival in CLL. In addition, the demonstrated safety and activity of genetically modified chimeric antigen receptor (CAR) T cells present the opportunity of harnessing the power of the immune system to kill CLL cells without the need for SCT. We attempt to define the role of SCT in the era of targeted therapies and discuss questions that remain to be answered. Furthermore, we highlight the potential for exciting new cellular therapy using genetically modified anti-CD19 CAR T cells and discuss its potential to alter treatment paradigms for CLL.

Predictors of outcome in reduced intensity allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia: summarizing the evidence and highlighting the limitations

Several studies have reported the prognostic significance of various clinical, genetic, biologic and molecular markers on postallogeneic hematopoietic cell transplantation outcomes such as nonrelapse mortality, relapse and survival. Notwithstanding limitations, existence of refractory/progressive disease at allografting yields worse nonrelapse mortality, more relapse and inferior overall survival. Advanced age results in higher nonrelapse mortality and increased relapse risk. Presence of poor-risk cytogenetics increases post-transplant relapse risk, but its impact on overall survival appears controversial. Developing prognostic models using large multicenter data could help better understand the effect of these and other variables on post-transplant outcomes. Newly discovered mutations as well as response (or not) to new potent therapies, such as ibrutinib or others, would likely be incorporated in such models.

Paradigm shifts in the management of poor-risk chronic lymphocytic leukemia

With the growing complexity of treatment options for chronic lymphocytic leukemia (CLL) and variables that influence the underlying biology of this disease, providing allogeneic stem cell transplant (alloSCT) to appropriate candidates poses a challenge for transplant physicians. Novel small molecule inhibitors hold unprecedented promise for poor-risk subgroups, which will likely alter decision-making and referral patterns for transplant. In this review, we analyze what is known and may still remain true about indications for transplant based on outcomes reported in the literature recently and over the last decade.

Genomic aberrations deletion 11q and deletion 17p independently predict for worse progression-free and overall survival after allogeneic hematopoietic cell transplantation for chronic lymphocytic leukemia

Chronic lymphocytic leukemia remains incurable despite availability of potent chemoimmunotherapy regimens. Allogeneic hematopoietic cell transplantation (HCT) is the only modality that offers the possibility of cure. To identify predictors of progression-free and overall survival, we evaluated outcomes of 43 consecutive patients who received an allograft for advanced CLL. The majority received a reduced intensity conditioning regimen (n=37). Donors were HLA matched-related (n=18), matched-unrelated (n=15), mismatched-unrelated (n=7), or umbilical cord blood (n=3). The median progression-free (PFS) and overall survival (OS) were 31.4 months and 46.4 months respectively. Twenty (46.5%) patients were alive and in complete remission at a median follow-up of 31.4 months. NRM was higher than previously published series for CLL, likely due to a high burden of comorbidity (22 patients with HCT-CI ≥ 2) and a high proportion receiving HLA mismatched-unrelated donor or umbilical cord blood cells. Presence of del (11q), del(17p), or progressive disease at HCT are independent predictors of worse PFS and OS. New strategies are needed to improve survival outcomes in CLL associated with poor risk cytogenetics.

Immunotherapy for chronic lymphocytic leukemia in the era of BTK inhibitors

Understanding the pathogenesis of CLL has uncovered a plethora of novel targets for human application of monoclonal antibodies, engineered T cells, or inhibitors of signal transduction pathways. The B-cell receptor signaling pathway is being actively explored as a therapeutic target in CLL. Ibrutinib, an inhibitor of Bruton's tyrosine kinase is showing impressive responses in heavily pre-treated high-risk CLL, whether alone or in combination with MoAbs or chemotherapy. Other key components of the BCR pathway, namely PI3K-δ, are also being targeted with novel therapies with promising results as well. Future trials would likely evaluate ibrutinib in the front-line setting. Moreover, improvements in allogeneic HCT mostly by continuing to reduce associated toxicity as well as incorporating cellular therapies such as autologous CLL tumor vaccines, among others, will continue to expand. This is also the case for the next generation of chimeric antigen receptor therapy for CLL once genetically modified T cells are available at broad scale and with improved efficacy. As our ability to further refine and integrate these therapies continues to improve, and we gain further knowledge from gene sequencing, we anticipate that treatment algorithms will continue to be revised to a more personalized approach to treat this disease with improved efficacy and devoid of unnecessary toxicity.

Rapid complete donor lymphoid chimerism and graft-versus-leukemia effect are important in early control of chronic lymphocytic leukemia

Eradication of minimal residual disease (MRD) after allotransplantation in persons with chronic lymphocytic leukemia (CLL) is associated with lower rates of relapse. Rapid engraftment of donor lymphocyte elements can contribute to MRD control, but it remains unclear whether this strategy will benefit patients. In this study, we report the incidence of MRD eradication and graft-versus-host disease (GvHD) in persons with rapid versus later donor T lymphocyte engraftment after lymphodepleting chemotherapy and reduced intensity conditioning (RIC) allotransplantation. Twenty-seven subjects received lymphodepleting chemotherapy to facilitate donor engraftment followed by fludarabine and cyclophosphamide RIC and a blood cell allograft. MRD was monitored by multicolor flow cytometry after transplantation. Complete donor T lymphoid chimerism (TLC) and myeloid chimerism (MC) were achieved in 25 subjects at a median of 28 days (range, 14-60 days) and 21 days (range, 14-180 days), respectively. Achieving complete donor TLC by day 14 versus day 28 or later correlated with occurrence of grade 2 or higher acute GvHD (90% [95% confidence interval {CI}, 78-100%] versus 35% [95% CI, 16-54%]; p = 0.014) and better control of MRD in the bone marrow at day 100, median 0% (range, 0-0.1%) versus 8.5% (range, 0-92%; p = 0.016). Among 11 persons with early donor TLC, none had progressive disease, and seven died of treatment -related mortality (TRM). In persons with later development of TLC, 8 of 16 had progressive disease and 2 died of TRM. Time to donor myeloid chimerism had no effect on outcomes. Rapid establishment of donor TLC resulted in more complete eradication of early MRD, but greater incidence of acute GvHD and TRM in persons with CLL undergoing RIC allotransplantation.

An unusual presentation of a chronic lymphocytic leukemia patient with 17p deletion after reduced-intensity transplantation: Richter syndrome and concomitant graft-versus-host disease--case report

Chronic lymphocytic leukemia (CLL) patients with 17p deletion comprise a challenging subgroup associated with poor overall survival. These patients should be treated with alternative strategies. Reduced-intensity conditioning (RIC) allogeneic stem cell transplantation (allo-SCT) can achieve long-term remission in this ultra-high-risk CLL group. Herein, we described a CLL patient with 17p deletion who developed Richter syndrome with extranodal involvement of the liver soon after RIC allo-SCT despite apparent acute graft-versus-host disease. The majority of chronic lymphocytic leukemia (CLL) patients respond well to chemoimmunotherapy. Patients who show ultra-high-risk genetics, such as 17p deletions, comprise a challenging subgroup of patients with poor response to chemoimmunotherapy and median life expectancy <2-3 years at the time of first-line treatment. Current treatment approaches for patients with 17p deletion include agents acting independently from the DNA damage pathway, such as alemtuzumab and high-dose corticosteroids. RIC allo-SCT for consolidation can achieve long-term remission in this ultra-high-risk CLL group.(1,2) Richter syndrome (RS) represents the clinicopathologic transformation of CLL to an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL).(3) RS appearing after allo-SCT can be managed by tapering of immunosuppression, followed by dose-escalated donor lymphocyte infusion titrated to the degree of leukemia response and graft-versus-host disease (GVHD) encountered.(4) Herein, we describe a CLL patient with 17p deletion who developed RS with extranodal involvement of the liver soon after RIC allo-SCT despite apparent acute GVHD (aGVHD).

Patterns of patient specific dosimetry in total body irradiation

PURPOSE

Total body irradiation (TBI) has been used for bone marrow transplant for hematologic and immune deficiency conditions. The goal of TBI is to deliver a homogeneous dose to the entire body, with a generally accepted range of dose uniformity being within ± 10% of the prescribed dose. The moving table technique for TBI could make dose uniform in whole body by adjusting couch speed. However, it is difficult to accurately estimate the actual dose by calculation and hence in vivo dosimetry (IVD) is routinely performed. Here, the authors present patterns of patient-specific IVD in 161 TBI patients treated at our institution.

METHODS

Cobalt-60 teletherapy unit (Model C9 Cobalt-60 teletherapy unit, Picker X-ray Corporation) with customized moving bed (SITI Industrial Products, Inc., Fishers, IN) were used for TBI treatment. During treatment, OneDose(TM) (Sicel Technology, NC) Metal Oxide-silicon Semiconductor Field Effect Transistor detectors were placed at patient body surface; both entrance and exit side of the beam at patient head, neck, mediastinum, umbilicus, and knee to estimate midplane dose. When large differences (>10%) between the prescribed and measured dose were observed, dose delivery was corrected for subsequent fractions by the adjustment of couch speed and/or bolus placement. Under IRB exempt status, the authors retrospectively analyzed the treatment records of 161 patients who received TBI treatment between 2006 and 2011.

RESULTS

Across the entire cohort, the median ± SD (range) percent variance between calculated and measured dose for head, neck, mediastinum, umbilicus, and knee was -2.3 ± 10.2% (-66.2 to +35.3), 1.1 ± 11.5% (-62.2 to +40.3), -1.9 ± 9.5% (-66.4 to +46.6), -1.1 ± 7.2% (-35.2 to +42.9), and 3.4 ± 12.2% (-47.9 to +108.5), respectively. More than half of treatments were within ± 10% of the prescribed dose for all anatomical regions. For 80% of treatments (10%-90%), dose at the umbilicus was within ± 10%. However, some large differences greater than 35% were also found at several points. For one case, the knee received double the prescribed dose. When the dose differences for multiple fractions were averaged, compliance (± 1 0%) between the prescription and measured dose was improved compared to the dose difference of the first single fraction, for example, as at umbilicus, which improved from 83.9% to 98.5%.

CONCLUSIONS

Actual dose measurement analysis of TBI patients revealed a potentially wide variance from the calculated dose. Based from their IVD method for TBI using Cobalt-60 irradiator and moving table, ± 10% over entire body is hard to achieve. However, it can be significantly improved with immediate feedback after the first fraction prior to subsequent treatments.

ESMO Guidelines consensus conference on malignant lymphoma 2011 part 1: diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL) and chronic lymphocytic leukemia (CLL)

To complete the existing treatment guidelines for all tumor types, ESMO organizes consensus conferences to better clarify open issues in each disease. In this setting, a consensus conference on the management of lymphoma was held on 18 June 2011 in Lugano, immediately after the end of the 11th International Conference on Malignant Lymphoma. The consensus conference convened ∼45 experts from all around Europe and selected six lymphoma entities to be addressed; for each of them three to five open questions were to be discussed by the experts. For each question, a recommendation should be given by the panel, supported by the strength of the recommendation based on the level of evidence. This consensus report focuses on the three most common lymphoproliferative malignancies: diffuse large B-cell lymphoma, follicular lymphoma and chronic lymphocytic leukemia. A second report will concentrate on mantle cell lymphoma, marginal zone lymphoma and T-cell lymphomas.

A look into the future: can minimal residual disease guide therapy and predict prognosis in chronic lymphocytic leukemia?

Over the past 2 decades, dramatic improvements in the efficacy of treatments for chronic lymphocytic leukemia have led to progressively higher percentages of clinical complete remissions. A molecular eradication of the leukemia has become not only a desirable, but also an achievable, end point that needs to be evaluated within clinical trials. The assessment of complete remission only at the clinical and morphological level is insufficient, at least for physically fit patients. The detection of minimal residual disease (MRD) in chronic lymphocytic leukemia has become feasible using PCR-based or flow cytometric techniques that reproducibly allow reaching the detection level of less than 1 leukemic cell per 10 000 leukocytes (10−4), the level currently defined as MRD− status. Emerging data indicate that the MRD status during and at the end of treatment is one of the most powerful predictors of progression-free and overall survival. This predictor appears to be independent of clinical response, type or line of therapy, and known biological markers. For these reasons, the time is ripe to test the use of MRD as a surrogate marker of clinical end points and as a real-time marker of efficacy and/or resistance to the administered therapies. In the near future, clinical trials will determine whether MRD assessment can be used for guiding therapy, either to improve quality of responses through consolidation or to prevent relapses through preemptive therapies based on the reappearance of MRD.

Therapeutic advancement of chronic lymphocytic leukemia

Despite the combinations of chemotherapy with monoclonal antibodies have further improved response rates, chronic lymphocytic leukemia (CLL) remains an incurable disease with an extremely variable course. This article reviews the ongoing clinical advances in the treatment of CLL in both previously untreated and relapsed disease and focuses on the benefit of different therapeutic strategies, the most effective therapy combinations and the potential activity of novel agents. Novel agents and combination therapies have been investigated by several studies in both the upfront and relapsed setting, particularly for patients with 17p deletion, TP53 mutation and fludarabine-refractory CLL. While these agents and combination therapies have improved initial response rates, ongoing studies are continued to determine and improve the efficacy and safety. Despite advancements in the treatment of CLL have led to high response rates, allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative option and reduced-intensity conditioning (RIC) allo-HSCT must be strongly considered whenever feasible. As such, ongoing studies of these agents and other novel approaches in clinical development are needed to expand and improve treatment options for CLL patients.

Long-term follow-up of reduced-intensity allogeneic stem cell transplantation for chronic lymphocytic leukemia: prognostic model to predict outcome

CLL remains incurable with chemoimmunotherapy, and allogeneic hematopoietic stem cell transplantation (HSCT) offers potential for cure. We assessed the outcomes of 108 CLL patients undergoing first allogeneic HSCTs, 76 with reduced intensity (RIC) and 32 with myeloablative (MAC) conditioning between 1998 and 2009 at Dana-Farber Cancer Institute. With median follow-up 5.9 years in surviving patients, the 5 year OS for the entire cohort is 63% for RIC regimens and 49% for MAC regimens (p=0.18). The risk of death declined significantly starting in 2004 and we found that 5 year OS for HSCT between 2004–2009 was 83% for RIC regimens compared to 47% for MAC regimens (p=0.003). For RIC transplantation, we developed a prognostic model based on predictors of PFS, specifically remission status, LDH, comorbidity score and lymphocyte count, and found 5-year PFS 83% for score 0, 63% for score 1, 24% for score 2, and 6% for score >= 3 (p<0.0001). We conclude that RIC HSCT for CLL in the current era is associated with excellent long-term PFS and OS, and, as potentially curative therapy, should be considered early in the disease course of relapsed high-risk CLL patients.

Novel therapies and their integration into allogeneic stem cell transplant for chronic lymphocytic leukemia

Over the past decade, numerous advances have been made in elucidating the biology of and improving treatment for chronic lymphocytic leukemia (CLL). These studies have led to identification of select CLL patient groups that generally have short survival dating from time of treatment or initial disease relapse who benefit from more aggressive therapeutic interventions. Allogeneic transplantation represents the only potentially curative option for CLL, but fully ablative regimens applied in the past have been associated with significant morbidity and mortality. Reduced-intensity preparative regimens has made application of allogeneic transplant to CLL patients much more feasible and increased the number of patients proceeding to this modality. Arising from this has been establishment of guidelines where allogeneic stem cell transplantation should be considered in CLL. Introduction of new targeted therapies with less morbidity, which can produce durable remissions has the potential to redefine where transplantation is initiated in CLL. This review briefly summarizes the field of allogeneic stem cell transplant in CLL and the interface of new therapeutics with this modality.

Can prognostic factors be used to direct therapy in chronic lymphocytic leukemia?

Chronic lymphocytic leukemia (CLL) shows a heterogeneous clinical course, which can be explained in part by prognostic factors. Most patients do not need treatment at the time of first diagnosis. The identification of prognostic factors is of major interest if strategies can be devised to treat patients according to their individual risk profile or biological subgroup. Currently, in spite of a wealth of prognostic factors, individualized treatment approaches in different genetic or risk groups are the exemption in CLL. This review summarizes the most important prognostic and predictive factors in CLL, with particular emphasis on factors affecting treatment decisions in clinical trials and routine practice.

Hematopoietic Stem Cell Allografting for Chronic Lymphocytic Leukemia: A Focus on Reduced-Intensity Conditioning Regimens

Background

Allogeneic hematopoietic cell transplantation (allo-HCT) remains the only known treatment modality that currently offers a potential cure to patients with chronic lymphocytic leukemia (CLL). A better understanding of the role of adoptive immunotherapy and its consequent bona fide graft-vs-leukemia (GVL) effect has resulted in a reduction of the ablative intensity and toxicity of preparative allo-HCT regimens.

Methods

The authors review the published data of reduced-intensity conditioning (RIC) allo-HCT in patients with CLL.

Results

RIC allo-HCT has reduced the transplant associated morbidity and mortality of the procedure and has consequently broadened applicability of allo-HCT to patients with CLL who are generally of more advanced age (> 60 years) and who often have associated comorbidities.

Conclusions

Published literature supports the use of RIC allo-HCT for these patients once a suitable donor is identified, provided they fulfill acceptable consensus criteria for hematopoietic stem cell allografting. Several studies have shown that T-cell-replete RIC allo-HCT is also capable of overcoming the adverse effect of poor prognostic factors in CLL such as del(17p), unmutated IgVH, or ZAP-70 expression. Continued clinical trials to identify the optimal regimen for RIC allo-HCT for patients with CLL are warranted.

Salvage therapy for relapsed chronic lymphocytic leukemia

Chronic lymphocytic leukemia is a common hematologic malignancy with a highly variable clinical course. While the median age at diagnosis is 72 years of age and fewer than 10% of patients are diagnosed before the age of 60 years, the majority of patients who require therapy will ultimately relapse. Advances in upfront therapy and supportive care have dramatically improved initial responses compared with traditional akylator-based chemotherapy. However, comparable results are not generally observed in the salvage setting. Careful planning that takes into account the duration of the initial response, patient age and/or comorbidities, and cytogenetic and molecular profiles are critical for the successful management of patients with relapsed chronic lymphocytic leukemia.

Treatment options for high-risk chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common form of leukaemia in the Western world. The natural history of CLL is extremely variable with a survival time from initial diagnosis that ranges from 2 to more than 20 years. Understanding the clinical diversity and allowing the subclassification of CLL into various prognostic groups not only assists in predicting future outcome for patients, but also helps to direct treatment decisions. Chlorambucil and fludarabine were the standard therapy for CLL for decades. Randomized studies have reported superior overall response and progression-free survival (PFS) for fludarabine compared with alkylator-based therapy and for the fludarabine-cyclophospamide (FC) combination over fludarabine alone. More recently the addition of rituximab to the FC regimen (R-FC) has shown significant improvement in overall response, PFS and overall survival compared with FC alone. However, there are patients for whom this regimen still provides less satisfactory results. Within the above studies CLL patients who have some of the poorer prognostic markers, such as unmutated IgVH genes and/or high beta-2 microglobulin (B2M), and those who fail to achieve a minimal residual disease (MRD) negative remission are likely to have a shorter PFS compared with those without these features. Various strategies have been explored to improve the outcome for such patients. These include the addition of agents to a frontline R-FC regimen, use of consolidation and consideration of maintenance. The only group that can be clearly identified pretreatment for whom conventional fludarabine-based therapies produce significantly inferior response rates, PFS and overall survival are the patients who harbour a genetic fault; deletion or mutation or a combination of deletion and mutation of tumour protein p53 (TP53). TP53 inactivation is a less common finding at first treatment but becomes much more common in fludarabine-refractory patients. Alemtuzumab and high-dose corticosteroids have been shown to be effective in this group of CLL patients. Trials combining these two agents have shown improved responses, particularly for those patients with bulky nodal disease for whom alemtuzumab alone may be insufficient. Since the duration of responses remains relatively short, suitable patients should be considered for allogeneic stem cell transplantation according to the European Group for Blood and Marrow Transplantation (EBMT) guidelines. Furthermore, there are a number of other new treatments on the horizon, including humanized antibodies directed against novel targets and small-molecule inhibitors.

Clinicobiologic importance of cytogenetic lesions in chronic lymphocytic leukemia

Molecular cytogenetic lesions play a major role in the pathogenesis of chronic lymphocytic leukemia (CLL) and represent important prognostic markers. Besides FISH, conventional banding analysis using effective mitogens is important for an accurate assessment of the cytogenetic profile of CLL. The most frequent aberrations are represented by 13q-, 11q-, +12, 6q- and 14q32/IGH translocations and 17p-. Chromosome translocations and complex karyotype may occur in up to 30 and 16% of the cases, respectively. The frequency of 17p- and 11q- is higher in patients requiring treatment and in relapsed/refractory patients, reflecting the association of these rearrangements with unfavorable prognosis. Mutations of the TP53 gene may also confer an inferior outcome, as is the case with 14q32 translocations and unbalanced translocations. Evidence was provided that distinct treatment approaches may be effective in specific cytogenetic entities of CLL, making molecular cytogenetic investigations a necessary tool for a modern diagnostic work-up in CLL.

Nonmyeloablative allogeneic stem cell transplantation in relapsed/refractory chronic lymphocytic leukemia: long-term follow-up, prognostic factors, and effect of human leukocyte histocompatibility antigen subtype on outcome

BACKGROUND

The role of nonmyeloablative allogeneic stem cell transplantation (NST) in the treatment of chronic lymphocytic leukemia (CLL) is not well established. The authors report on long-term experience with NST in relapsed/refractory CLL and define prognostic factors associated with outcome.

METHODS

The authors reviewed the outcome of 86 patients with relapsed/relapsed CLL enrolled in sequential NST protocols.

RESULTS

The median patient age was 58 years. Patients were heavily pretreated before transplantation, and 43 required immunomanipulation after NST for persistent or recurrent disease. Immunomanipulation included withdrawal of immunosuppression, rituximab, and step-wise donor lymphocyte infusions. Of 43 patients receiving immunomanipulation, 20 (47%) experienced a complete remission. Patients with human leukocyte antigen (HLA) genotype A1(+) /A2(-) /B44(-) were more likely to experience a complete remission (P = .0009), with rates of 9%, 36%, 50%, and 91%, respectively, for 0, 1, 2, and 3 of these HLA factors. This resulted in significant improvement in progression-free-survival rates of 68.2% at 5 years for patients with all 3 HLA factors. Overall, the estimated 5-year survival rate was 51%. In a multivariate model, a CD4 count of <100/mm(3) and a below normal serum immunoglobulin G level at study entry were associated with a short survival duration (P < .0001).

CONCLUSIONS

These results confirm the potential cure of relapsed/refractory CLL with NST and provide the first evidence that immunoglobulin G and CD4 levels are predictive of overall survival after NST in CLL and that human leukocyte antigen alleles predict response to immunomanipulation.

Allogeneic stem cell transplantation for chronic lymphocytic leukemia: lessons to be learned from minimal residual disease studies

Allogeneic stem cell transplantation (alloSCT) is a potentially curative treatment strategy for poor-risk chronic lymphocytic leukemia (CLL). The crucial anti-leukemic principle of alloSCT in CLL appears to be the graft-versus-leukemia effect (GVL). Evidence for GVL in CLL is particularly provided by studies analysing the kinetics of minimal residual disease (MRD). The purpose of this review is to summarize the methodologies of MRD assessment, its proven benefits and its further perspectives for optimizing the outcome of transplantation. Proven value of quantitative MRD monitoring by RQ-PCR or MRD-flow consists in using it as an indicator of long-term disease control and potential cure. As MRD kinetics correlates with GVL activity, its suitability for guiding GVL-inducing immunomodulation is currently under investigation. In conclusion, quantitative MRD monitoring seems to be mandatory to assure safe and effective immunotherapy in the context of alloSCT for CLL, which should, however, be best performed within clinical studies.

Stem cell transplantation in chronic lymphocytic leukaemia - steering a safe course over shifting sands

There is no clear consensus regarding the optimal management of chronic lymphocytic leukaemia. Many patients are diagnosed at an advanced age and will die with chronic lymphocytic leukaemia, but of other unrelated causes. A significant minority are diagnosed at an earlier age, or with more aggressive disease, and despite chemotherapy, are likely to die of chronic lymphocytic leukaemia. The infusion of autologous or allogeneic haemopoietic stem cells, following a variety of conditioning regimes, offers the possibility of longer remissions or even cure. We explore the key questions facing clinicians in this field: Who is it best to transplant? When is it best to transplant? How is it best to transplant?

Allogeneic stem cell transplantation provides durable disease control in poor-risk chronic lymphocytic leukemia: long-term clinical and MRD results of the German CLL Study Group CLL3X trial

The purpose of this prospective multicenter phase 2 trial was to investigate the long-term outcome of reduced-intensity conditioning allogeneic stem cell transplantation (alloSCT) in patients with poor-risk chronic lymphocytic leukemia. Conditioning was fludarabine/ cyclophosphamide-based. Longitudinal quantitative monitoring of minimal residual disease (MRD) was performed centrally by MRD-flow or real-time quantitative polymerase chain reaction. One hundred eligible patients were enrolled, and 90 patients proceeded to alloSCT. With a median follow-up of 46 months (7-102 months), 4-year nonrelapse mortality, event-free survival (EFS) and overall survival (OS) were 23%, 42%, and 65%, respectively. Of 52 patients with MRD monitoring available, 27 (52%) were alive and MRD negative at 12 months after transplant. Four-year EFS of this subset was 89% with all event-free patients except for 2 being MRD negative at the most recent assessment. EFS was similar for all genetic subsets, including 17p deletion (17p−). In multivariate analyses, uncontrolled disease at alloSCT and in vivo T-cell depletion with alemtuzumab, but not 17p−, previous purine analogue refractoriness, or donor source (human leukocyte antigen-identical siblings or unrelated donors) had an adverse impact on EFS and OS. In conclusion, alloSCT for poor-risk chronic lymphocytic leukemia can result in long-term MRD-negative survival in up to one-half of the patients independent of the underlying genomic risk profile. This trial is registered at http://clinicaltrials.gov as NCT00281983.

Standards for the treatment of relapsed chronic lymphocytic leukemia: a case-based study

In recent years, considerable advances have been made in first-line treatment strategies for chronic lymphocytic leukemia (CLL). Combination of conventional chemotherapy with immunotherapeutic agents is currently considered the most active strategy, with improved progression-free survival and overall survival. However, patients are not cured and invariably experience relapsing disease requiring treatment. In contrast to the advances made in first-line treatment strategies, much less progress has been made for patients with relapsed and especially refractory CLL. The activity of most chemotherapeutic drugs used in CLL rely on intact p53 function, and repeated cycles of therapy might eventually result in drug resistance because of acquired cytogenetic alterations, mainly affecting genes involved in the p53 response. As a consequence, most commonly used treatment regimens are ineffective in patients with refractory disease. A number of promising alternative treatment approaches are currently under investigation. In this review, the approach to patients with relapsed and refractory CLL and current promising experimental treatment options for these distinct clinical patient categories are discussed.

Allogeneic transplantation for chronic lymphocytic leukemia

Even if Chronic lymphocytic leukemia (CLL) often has an indolent behavior with good responsiveness to cytoreductive treatment, about 20% of the patients, so called “poor-risk” patients, show an aggressive course and die within a few years despite early intensive therapies. Criteria for poor-risk disease according to the European Bone Marrow Transplantation (EBMT) CLL Transplant Consensus are: purine analogue refractoriness, early relapse after purine analogue combination therapy, CLL with p53 lesion requiring treatment.

Allogeneic transplant has potential curative role in CLL, however burden with very high transplant related mortality (TRM) rates of 38–50%. A major advance in reducing the short-term morbidity and mortality of allogeneic stem cell transplantation (SCT) has been the introduction of non-myeloablative or reduced intensity conditioning (RIC) regimens to allow engraftment of allogeneic stem cells. There is no doubt that the crucial therapeutic principle of allo-SCT in CLL is graft versus leukemia (GVL) activity.

The major complications of allogeneic SCT in CLL are: chronic graft-versus-host-disease (GVHD) affecting quality of life, high graft rejection and infection rates correlated with preexisting immunosuppression. Disease relapse remains the major cause of failure after RIC allo-HCT in CLL patients.

Sensitive minimal residual disease (MRD) quantification has strong prognostic impact after transplant.

Eradicating minimal residual disease in chronic lymphocytic leukemia: should this be the goal of treatment?

Even though chronic lymphocytic leukemia (CLL) is the most prevalent leukemia of the Western world, the development of treatment approaches for CLL has lagged behind the development of approaches to various other hematologic malignancies for a variety of reasons. In recent years, the treatment approach to patients with CLL has evolved rapidly, with the addition of several new prognostic markers, highly effective immunochemotherapy combinations, and attainment of remission up to the point of the eradication of minimal residual disease (MRD). Highly sensitive methods now available to detect MRD can detect a single CLL cell in 10(4) leukocytes using either allele-specific oligonucleotide polymerase chain reaction or four-color or six-color flow cytometry. Over the past decade, several studies have examined the possible advantage of MRD eradication in CLL. This article reviews our current understanding of MRD eradication and analyzes whether it is a desirable goal in the routine clinical treatment of CLL, which will optimize the management of individual patients.

NCI first international workshop on the biology, prevention, and treatment of relapse after allogeneic hematopoietic stem cell transplantation: report from the committee on disease-specific methods and strategies for monitoring relapse following allogeneic stem cell transplantation. part II: chronic leukemias, myeloproliferative neoplasms, and lymphoid malignancies

Relapse has become the major cause of treatment failure after allogeneic hematopoietic stem cell transplantation. Outcome of patients with clinical relapse after transplantation generally remains poor, but intervention prior to florid relapse improves outcome for certain hematologic malignancies. To detect early relapse or minimal residual disease, sensitive methods such as molecular genetics, tumor-specific molecular primers, fluorescence in situ hybridization (FISH), and multiparameter flow cytometry (MFC) are commonly used after allogeneic stem cell transplantation to monitor patients, but not all of them are included in the commonly employed disease-specific response criteria. The highest sensitivity and specificity can be achieved by molecular monitoring of tumor- or patient-specific markers measured by polymerase chain reaction-based techniques, but not all diseases have such targets for monitoring. Similar high sensitivity can be achieved by determination of recipient-donor chimerism, but its specificity regarding detection of relapse is low and differs substantially among diseases. Here, we summarize the current knowledge about the utilization of such sensitive monitoring techniques in chronic leukemias, myeloproliferative neoplasms, and lymphoid malignancies based on tumor-specific markers and cell chimerism and how these methods might augment the standard definitions of posttransplant remission, persistence, progression, relapse, and the prediction of relapse. Critically important is the need for standardization of the different residual disease techniques and to assess the clinical relevance of minimal residual disease and chimerism surveillance in individual diseases, which in turn must be followed by studies to assess the potential impact of specific interventional strategies.

Comparison of cladribine plus cyclophosphamide with fludarabine plus cyclophosphamide as first-line therapy for chronic lymphocytic leukemia: a phase III randomized study by the Polish Adult Leukemia Group (PALG-CLL3 Study)

PURPOSE Little is known about comparison of the activity of different purine nucleoside analogs in chronic lymphocytic leukemia (CLL). We conducted a randomized phase III trial to compare efficacy and safety of cladribine and fludarabine, each combined with cyclophosphamide, in previously untreated progressive CLL. PATIENTS AND METHODS Patients received cladribine at 0.12 mg/kg combined with cyclophosphamide at 250 mg/m(2) for 3 days intravenously (CC regimen) or fludarabine at 25 mg/m(2) combined with cyclophosphamide at 250 mg/m(2) for 3 days intravenously (FC regimen), every 28 days for up to six cycles. The primary end point was complete response (CR) rate. Secondary end points included overall response rate (ORR), progression-free survival (PFS), overall survival (OS), and treatment-related toxicity. RESULTS Of 423 randomly assigned patients (211 to CC and 212 to FC), 395 were evaluated in the final analysis. The CR and ORR reached 47% and 88% in the CC arm and 46% and 82% in the FC arm (P = .25 and P = .11, respectively). The median PFS was 2.34 years with CC and 2.27 years with FC (P = .51). OS and grade 3/4 treatment-related toxicity were also comparable. Moreover, we did not observe any significant differences in CC and FC efficacy across different patient prognostic subgroups that included patients with 17p13 (TP53 gene) deletion who had poor survival in both study arms. CONCLUSION Cladribine and fludarabine in combination with cyclophosphamide are equally effective and safe first-line regimens for progressive CLL. Both combinations have unsatisfactory activity in patients with 17p13 (TP53 gene) deletion.

Transplantation in chronic lymphocytic leukemia: timing and expectations

Stem cell transplantation in chronic lymphocytic leukemia (CLL) is an evolving field. Younger patients with high-risk disease might derive the greatest benefit from this approach and the availability of reduced-intensity conditioning regimens has made allogeneic stem cell transplantation more relevant to patients with CLL. Patient selection, timing of transplantation, and method of conditioning, stem cell delivery and immunosuppression appear to influence outcomes. We collect and review the available data to assist clinical decision-making in this field.

Monoallelic and biallelic inactivation of TP53 gene in chronic lymphocytic leukemia: selection, impact on survival, and response to DNA damage

Deletion of TP53 gene, under routine assessment by fluorescence in situ hybridization analysis, connects with the worst prognosis in chronic lymphocytic leukemia (CLL). The presence of isolated TP53 mutation (without deletion) is associated with reduced survival in CLL patients. It is unclear how these abnormalities are selected and what their mutual proportion is. We used methodologies with similar sensitivity for the detection of deletions (interphase fluorescence in situ hybridization) and mutations (yeast functional analysis) and analyzed a large consecutive series of 400 CLL patients; a subset of p53–wild-type cases (n = 132) was screened repeatedly during disease course. The most common type of TP53 inactivation, ie, mutation accompanied by deletion of the remaining allele, occurred in 42 patients (10.5%). Among additional defects, the frequency of the isolated TP53 mutation (n = 20; 5%) and the combination of 2 or more mutations on separate alleles (n = 5; 1.3%) greatly exceeded the sole deletion (n = 3; 0.8%). Twelve patients manifested defects during repeated investigation; in all circumstances the defects involved mutation and occurred after therapy. Monoallelic defects had a negative impact on survival and impaired in vitro response to fludarabine. Mutation analysis of the TP53 should be performed before each treatment initiation because novel defects may be selected by previous therapies.