Ibrutinib as a salvage therapy after allogeneic HCT for chronic lymphocytic leukemia

Allogeneic stem cell transplantation achieves long-term remissions in mantle cell lymphoma, including in TP53-mutated disease

Cytarabine-containing chemoimmunotherapy followed by autologous transplantation and rituximab maintenance achieves durable remissions for most patients with mantle cell lymphoma (MCL). However, patients with TP53-mutated disease have poor outcomes with standard approaches. We previously reported that allogeneic stem cell transplantation (alloSCT) achieved durable remissions in MCL, however follow-up among patients with TP53-mutated disease was limited. Here we report extended follow-up of the overall cohort (n = 36) and TP53-mutated subset (n = 13) (median follow-up 10.8 and 4.2 years, respectively). Estimated overall survival was 56% at 10 years for the overall cohort and 59% at 4 years for the TP53-mutated subset. Among patients with TP53-mutated disease, no relapses occurred beyond 6 months post-transplant. Survival after post-alloSCT disease relapse was poor (median 2.1 years). These data confirm that alloSCT can be curative in MCL, including patients with TP53-mutated disease, and should be considered for earlier utilization in this subgroup for whom conventional chemoimmunotherapy is ineffective.

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.

Cell therapy of chronic lymphocytic leukaemia: Transplants and chimeric antigen receptor (CAR)-T cells

There is substantial progress in the therapy of chronic lymphocytic leukaemia (CLL), much of it the result of new drug development. As such the definition of high-risk CLL is changing. Nevertheless, few persons with CLL are cured with current therapy. Two types of cell therapies of CLL are currently being evaluated or re-evaluated in the context of these advances: haematopoietic cell transplants and chimeric antigen receptor (CAR)-T-cells. We discuss the potential role of these cell therapies in the context of the evolving therapy topography of CLL including how these therapies work and who, if anyone, is an appropriate candidate for cell therapy.

Central Nervous System Involvement in Mantle Cell Lymphoma Presenting Magnetic Resonance Imaging Features of Mild Encephalitis/Encephalopathy with a Reversible Splenial Lesion

Mild encephalitis/encephalopathy with reversible splenial lesion (MERS) has not been described in lymphoma patients. A 65-year-old man with refractory mantle cell lymphoma (MCL) presented typical MRI features of MERS. The patient's cerebrospinal fluid contained an increased number of reactive T-cells; a small number of MCL cells were detected by immunoglobulin heavy chain-polymerase chain reaction (IGH-PCR). His symptoms and the splenial lesion resolved in response to ibrutinib treatment, although the patient eventually died of progressive MCL with overt leptomeningeal disease. We suggest that central nervous system involvement in MCL can present clinicoradiological features of MERS and that ibrutinib could be a choice of treatment.

Allogeneic Stem Cell Transplantation in Mantle Cell Lymphoma in the Era of New Drugs and CAR-T Cell Therapy

MCL is an uncommon lymphoproliferative disorder that has been regarded as incurable since its identification as a distinct entity. Allogeneic transplantation for two decades has represented the only option capable of ensuring prolonged remissions and possibly cure. Despite its efficacy, its application has been limited by feasibility limitations and substantial toxicity, particularly in elderly patients. Nevertheless, the experience accumulated over time has been wide though often scattered among retrospective and small prospective studies. In this review, we aimed at critically revise and discuss available evidence on allogeneic transplantation in MCL, trying to put available evidence into the 2020 perspective, characterized by unprecedented development of novel promising therapeutic agents and regimens.

Standard treatment approaches for relapsed/refractory chronic lymphocytic leukemia after frontline chemoimmunotherapy

Despite the effectiveness of chemoimmunotherapy (CIT), in most cases the clinical course of chronic lymphocytic leukemia (CLL) is characterized by consecutive episodes of disease progression and need for therapy. Treatment possibilities for patients with CLL in whom CIT fails whose disease progresses after initial CIT include pathway inhibitors (PIs) and, for selected patients, cellular therapy (ie, allogeneic stem cell transplant, chimeric antigen receptor T cells). PIs (ie, Bruton tyrosine kinase inhibitors, phosphatidylinositol 3-kinase inhibitors, and BCL2 inhibitors) are revolutionizing the treatment of CLL. PIs have proved to be more effective than CIT, both as upfront therapy and for relapsed/refractory disease, largely because they may overcome the negative impact of adverse biomarkers (eg, TP53 aberrations, unmutated IGHV) on outcomes and because of their acceptable toxicity. In this article, the management of patients with relapsed/refractory CLL is discussed, with a particular emphasis on the role of PIs.

Refractory and 17p-deleted chronic lymphocytic leukemia: improving survival with pathway inhibitors and allogeneic stem cell transplantation

Refractory/early relapsed and 17p deletion/p53 mutation (del(17p)/TP53mut)-positive chronic lymphocytic leukemia (CLL) has been conventionally considered a high-risk disease, potentially eligible for treatment with allogeneic stem cell transplantation (alloSCT). In this multicenter retrospective analysis of 157 patients, we compared the outcomes of patients with high-risk CLL treated with alloSCT, a B-cell receptor pathway inhibitor (BCRi), and both. Seventy-one patients were treated with BCRis, 67 patients underwent reduced-intensity conditioning alloSCT, and 19 received alloSCT with a BCRi before and/or after transplantation. Inverse probability of treatment weighting analyses were performed to compare the alloSCT and no-alloSCT groups; in the 2 groups, 5-year OS, PFS, and cumulative incidence of nonrelapse mortality (NRM) and relapse were 40% versus 60% (P = .096), 34% versus 17% (P = .638), 28% versus 5% (P = .016), and 38% versus 83% (P = .005), respectively. Patients treated with alloSCT plus BCRi had a 3-year OS of 83%. The 3-year OS and NRM by year of alloSCT, including patients treated with BCRi, were 53% and 17% in 2000 to 2007, 55% and 30% in 2008 to 2012, and 72% and 18% in 2013 to 2018. In conclusion, the combination of pathway inhibitors and alloSCT is feasible and may further improve the outcome of high-risk CLL patients.

Drug Review: Ibrutinib

Ibrutinib is an irreversible BTK inhibitor, characterized by high selectivity and potency. It has revolutionized the therapy of B-cell lymphomas, especially chronic lymphocytic leukemia (CLL) and mantle cell lymphoma. Importantly, it has expanded the armamentarium for those patients who are refractory to conventional chemoimmunotherapy. This small-molecule inhibitor has shown efficacy in this difficult-to-treat subset – those with del(17p)/TP53-mutated CLL. Its immunomodulatory properties make it an excellent choice for combining with other immunotherapeutic agents such as venetoclax. The drug is not without drawbacks. The need for indefinite therapy and the presence of adverse effects such as infection, bleeding, hypertension, and arrhythmia temper our enthusiasm for this versatile drug. But overall, ibrutinib's favorable risk profile and lack of myelosuppression make it an ideal therapy for the elderly and those with multiple comorbidities.

Impact and Intricacies of Bone Marrow Microenvironment in B-cell Lymphomas: From Biology to Therapy

Lymphoma, a group of widely prevalent hematological malignancies of lymphocyte origin, has become the focus of significant clinical research due to their high propensity for refractory/relapsed (R/R) disease, leading to poor prognostic outcomes. The complex molecular circuitry in lymphomas, especially in the aggressive phenotypes, has made it difficult to find a therapeutic option that can salvage R/R disease. Furthermore, the association of lymphomas with the Bone Marrow (BM) microenvironment has been found to portend worse outcomes in terms of heightened chances of relapse and acquired resistance to chemotherapy. This review assesses the current therapy options in three distinct types of lymphomas: diffuse large B-cell lymphoma, follicular lymphoma and mantle cell lymphoma. It also explores the role of the BM tumor microenvironment as a secure 'niche' for lymphoma cells to grow, proliferate and survive. It further evaluates potential mechanisms through which the tumor cells can establish molecular connections with the BM cells to provide pro-tumor benefits, and discusses putative therapeutic strategies for disrupting the BM-lymphoma cell communication.