Autografting CLL: the game is over!

Watch and Wait – Actualities in the Treatment of Chronic Lymphocytic Leukemia

In Western countries, chronic lymphocytic leukemia (CLL) is one of the most diagnosed leukemia types among elderly patients. CLL is described as an indolent lymphoproliferative disorder, characterized by the presence of a high number of small, mature B-cells in the peripheral blood smear, with a particular immunophenotype (CD5, CD19, CD23 positive and CD20 dim positive) and accumulation in the bone marrow and lymphoid tissue (e.g., lymph nodes, spleen). The experience of the past decades showed that CLL is clinically very heterogeneous; while some patients present a chronic clinical evolution, with a prolonged survival, in which the treatment can be delayed, others suffer from a more aggressive form, which must be treated early and is associated with many relapses. This observation led to several genomic studies that have mapped the genetic modifications involved in the disease conformations, including del(13q14), del(11q), or trisomy 12. On the other hand, certain genetic mutations such as del(17p13)–p53, NOTCH1 mutation, or ZAP70/CD38 increased expression are associated with worse clinical outcome. In order to apply the right treatment strategy, the RAI and BINET staging systems should be considered, which are based on clinical and laboratory assessment, on genetic mutations that may influence the resistance to chemotherapy, as well as the patient’s age and comorbidities. The aim of this manuscript was to present the therapeutic approaches of CLL, in order to attempt to answer the following question: to treat, or not to treat? This clinical update focuses on the managements of CLL patients in the 21st century.

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia among the adults in the Western World. CLL (and the corresponding nodal entity small lymphocytic lymphoma, SLL) is classified as a lymphoproliferative disorder characterised by the relentless accumulation of mature B-lymphocytes showing a peculiar immunophenotype in the peripheral blood, bone marrow, lymph nodes and spleen. CLL clinical course is very heterogeneous: the majority of patients follow an indolent clinical course with no or delayed treatment need and with a prolonged survival, while others experience aggressive disease requiring early treatment followed by frequent relapses. In the last decade, the improved understanding of CLL pathogenesis shed light on premalignant conditions (i.e., monoclonal B-cell lymphocytosis, MBL), defined new prognostic and predictive markers, improving patient stratification, but also broadened the therapeutic armamentarium with novel agents, targeting fundamental signaling pathways.

Pitting new treatments for chronic lymphocytic leukemia against old ones: how do they fare?

Significant progress has been made in the treatment of chronic lymphocytic leukemia (CLL) patients during the last two decades. In this review we present a personal case study for discussion on contemporary management in CLL. Presently immunochemotherapy using fludarabine, cyclophosphamide, and rituximab (FCR) is the standard upfront regimen for physically fit patients requiring treatment. Patients older than 65 years can be treated with modified doses of FCR, bendamustine, or chlorambucil combined with anti-CD20 antibody. This treatment can be repeated at relapse when the duration of response is over 2 years. Patients at high risk (with 17p deletion or early relapse) need alternative treatment with novel agents, e.g. ibrutinib or idelalisib. However, the optimal use of the novel agents in terms of duration, combinations, and long-term adverse effects is unknown. In selected eligible patients at high risk, allogeneic transplantation should be considered. Clinical trials in all stages of treatment are encouraged.

Autologous Stem Cell Transplantation for Chronic Lymphocytic Leukemia - Still a Valid Treatment Option, or is the Game Over?

Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab (FCR) has been established as the current standard of care for young and fit patients with chronic lymphocytic leukemia (CLL). In the early nineties of the last century, long before the advent of fludarabine or antibody-based strategies, there was realistic hope that myeloablative therapy followed by autologous stem cell transplantation (autoSCT) might be an effective and potentially curative front-line treatment option for suitable patients with CLL. Since then, several prospective trials have disenthralled this hope: although autoSCT can prolong event and progression-free survival if used as part of early front-line treatment, it does not improve overall survival, while it is associated with an increased risk of late adverse events such as secondary malignancies. In addition, autoSCT lacks the potential to overcome the negative impact of biomarkers that confer resistance to chemotherapy or early relapse. The role of autoSCT has also been explored in the context of FCR, and it was demonstrated that its effect is inferior to the currently established optimal treatment regimen. In view of ongoing attempts to improve on FCR, promising clinical activity of new substances even in relapsed/ refractory CLL patients, exciting novel cell therapy approaches and advantages in the understanding of the disease and detection of Minimal Residual Disease (MRD), autoSCT has lost its place as a standard treatment option for CLL.

Reappraising the role of autologous transplantation for indolent B-cell lymphomas in the chemoimmunotherapy era: is it still relevant?

The role of autologous hematopoietic cell transplantation (auto-HCT) in the management of indolent non-Hodgkin lymphomas (NHL) is shrouded in controversy. The outcomes of conventional therapies for many indolent lymphoma subtypes have dramatically improved over the last several years with the use of monoclonal antibodies, maintenance therapy programs and with the incorporation of radio-immunoconjugates. These significant advances in the armamentarium of lymphoma therapeutics warrant reappraisal of the current role of auto-HCT in the treatment algorithm of indolent NHL. Prospective randomized studies comparing contemporary chemoimmunotherapies against auto-HCT are lacking, leading to significant debate about the role and timing of auto-HCT for indolent NHL in the modern era. Although autografting for follicular lymphoma (FL) in first remission has been largely abandoned, it remains a useful modality for relapsed disease, especially for the subgroup of patients who are not candidates for allogeneic transplantation with a curative intent. Auto-HCT can provide durable disease control in chemosensitive transformed FL and mantle cell lymphoma (MCL) in first remission, with relatively low toxicity, and remains appropriate in chemoimmunotherapy era. Contemporary data are also reviewed to clarify the often underutilized role of autografting in relapsed MCL and other less frequent indolent NHL histologies. The biological basis of the increased risks of second malignancies with auto-HCT are reviewed to identify strategies designed to mitigate this risk by, for example, avoiding exposure to genotoxic agents, planning early stem cell collection/cryopreservation and minimizing the use of TBI with transplant conditioning, and so on. Genetic testing able to identify patients at high risk of therapy-related complications and novel post-transplant immune therapies with the potential of transforming autografting in indolent NHL from a remission-extending therapy to a curative modality are discussed to examine the possibly expanding role of auto-HCT for lymphoid malignancies in the coming years.

Transplant in chronic lymphocytic leukemia: to do it or not and if so, when and how?

Most patients with chronic lymphocytic leukemia (CLL) have an indolent clinical course, but the disease remains incurable with standard therapy and the prognosis is dismal for those patients with disease refractory to available treatment options. The only potentially curative treatment is allogeneic hematopoietic stem cell transplantation (SCT), but since CLL is a disease of elderly patients, few patients are candidates for myeloablative allogeneic SCT. Although autologous SCT is feasible and has low treatment-related mortality, it is not curative. The widespread adoption of reduced-intensity conditioning (RIC) allogeneic SCT has made this approach applicable to the elderly patient population with CLL. This approach relies on the documented graft-versus-leukemia (GVL) effect and is strong in CLL. Steps to further decrease the morbidity and mortality of the RIC SCT and in particular to reduce the incidence of chronic extensive graft-versus-host disease (GVHD) remain a major focus. Many potential treatments are available for CLL, and appropriate patient selection and SCT timing remain controversial and the focus of ongoing clinical trials. The use of SCT must always be weighed against the risk of the underlying disease, particularly in a setting where improvements in treatment are leading to improved outcome. The major challenge remains how to identify which patients with CLL merit this approach and where in the treatment course this treatment can be applied optimally.