Current treatment strategies in relapsed/refractory mantle cell lymphoma: where are we now?

Treatment Landscape of Relapsed/Refractory Mantle Cell Lymphoma: An Updated Review

Mantle cell lymphoma (MCL) accounts for nearly 2-6% of all non-Hodgkin lymphoma (NHL) cases, with a steady incidence increase over the past few decades. Although many patients achieve an adequate response to the upfront treatment, the short duration of remission with rapid relapse is challenging during MCL management. In this regard, there is no consensus on the best treatment options for relapsed/refractory (R/R) disease, and the international guidelines demonstrate wide variations in the recommended approaches. The last decade has witnessed the introduction of new agents in the treatment landscape of R/R MCL. Since the introduction of Bruton's tyrosine kinase (BTK) inhibitors, the treatment algorithm and response of R/R MCL patients have dramatically changed. Nevertheless, BTK resistance is common, necessitating further investigations to develop novel agents with a more durable response. Novel agents targeting the B-cell receptor (BCR) signaling have exhibited clinical activity and a well-tolerable safety profile. However, as the responses to these novel agents are still modest in most clinical trials, combination strategies were investigated in pre-clinical and early clinical settings to determine whether the combination of novel agents would exhibit a better durable response than single agents. In this report, we provide an updated literature review that covers recent clinical data about the safety and efficacy of novel therapies for the management of R/R MCL.

Management of Drug Resistance in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is a rare but aggressive B-cell hemopathy characterized by the translocation t(11;14)(q13;q32) that leads to the overexpression of the cell cycle regulatory protein cyclin D1. This translocation is the initial event of the lymphomagenesis, but tumor cells can acquire additional alterations allowing the progression of the disease with a more aggressive phenotype and a tight dependency on microenvironment signaling. To date, the chemotherapeutic-based standard care is largely inefficient and despite the recent advent of different targeted therapies including proteasome inhibitors, immunomodulatory drugs, tyrosine kinase inhibitors, relapses are frequent and are generally related to a dismal prognosis. As a result, MCL remains an incurable disease. In this review, we will present the molecular mechanisms of drug resistance learned from both preclinical and clinical experiences in MCL, detailing the main tumor intrinsic processes and signaling pathways associated to therapeutic drug escape. We will also discuss the possibility to counteract the acquisition of drug refractoriness through the design of more efficient strategies, with an emphasis on the most recent combination approaches.

Autophagy and Lymphoma

Lymphoma is a hematological malignancy and its incidence is growing. The use of CD20 monoclonal antibody improves the therapeutic efficacy in CD20-positive B-cell lymphoma. Despite remarkable progress in lymphoma treatment over the past decades, chemotherapy resistance and disease relapse become the main obstacles to further improve the prognosis of the patients. Therefore, the development of new treatment methods and drugs is urgently needed to improve the treatment of lymphoma. In tumors, autophagy functions to protect tumor cells from hypoxia, radiotherapy, and apoptosis. The ability to improve the prognosis of patients with lymphoma through the active regulation of autophagy represents a new approach to clinical treatment.

Current Approach to Non-Infectious Pulmonary Complications of Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is an established treatment for patients with a wide range of malignant and nonmalignant conditions. Noninfectious pulmonary complications still remain a leading cause of morbidity and mortality in these patients. Treating hematopoietic stem cell transplantation recipients with noninfectious pulmonary complications is still challenging, and the current treatment armamentarium and strategies are not adequate for patients receiving hematopoietic stem cell transplantation. Further trials are needed for a better description of the pathogenesis and the complete diagnostic criteria as well as for the development of effective therapeutic approaches for the management of noninfectious pulmonary complications of the hematopoietic stem cell transplantation. This review outlines the incidence, risk factors, pathogenesis, and clinical spectrum and discusses the current approaches to the management of noninfectious pulmonary complications of Hematopoietic stem cell transplantation.

Four-year follow-up of a single arm, phase II clinical trial of ibrutinib with rituximab (IR) in patients with relapsed/refractory mantle cell lymphoma (MCL)

Ibrutinib has shown significant activity in patients with relapsed or refractory mantle cell lymphoma (RR-MCL). We report the long-term outcome and safety profile of a single-centre, single arm, open-label, phase 2 study of RR-MCL treated with IR. Overall, the median follow-up time was 47 months (range 1-52 months), median duration on treatment was 16 months (range 1-53 months) and median number of treatment cycles was 17 (range 1-56). Twenty-nine patients (58%) achieved complete remission and of these, 12 patients continue on study. Thirty-eight patients discontinued treatment, 14 due to disease progression (2 transformed). Patients with blastoid morphology, high risk MCL International Prognostic Index score and high Ki67% had inferior survival. The commonest grade 1-2 toxicities were fatigue, diarrhoea, nausea, arthralgias and myalgias. None had long term toxicities. Median progression-free survival was 43 months. Eighteen patients (36%) died (14 deaths were MCL-related). The median overall survival has not been reached. Treatment with IR can provide durable remissions in a subset of patients with RR-MCL, especially those with low Ki67%. The possible benefit of adding other therapies in combination with IR in RR-MCL is under exploration.

Impact of novel therapies for mantle cell lymphoma in the real world setting: a report from the UK's Haematological Malignancy Research Network (HMRN)

The treatment landscape for mantle cell lymphoma (MCL) has changed dramatically in recent years, with findings from clinical trials reporting improvements in survival. Data on the general patient population are, however, sparse; and it is unclear whether the effects observed in clinical trials have translated into the real-world setting. To investigate this, we examined first-line and relapsed/refractory (RR) disease management in 335 MCL patients diagnosed between 2004 and 2015 in an established population-based patient cohort, along with data on demographic, diagnostic and prognostic factors. Marked treatment and survival changes were observed; first-line rituximab immunotherapy, for example, increased from 32% to 86% over the 11-year period, and median survival increased from 2·0 years among those first treated in 2004-2011 to 3·5 years among those treated in 2012-2015. Outcomes for RR disease also improved, from 8 months in 2004-2011 to 16·8 months in 2012-2015, coinciding with the introduction of agents, such as bendamustine and ibrutinib. Encouragingly, improvements were seen across all ages; 1-year overall survival among patients over 70 years treated for RR disease almost doubled. Our analyses underscore the importance of monitoring the impact of treatment changes in the real-world setting.

Pseudo-autologous stem cell transplantation for donor-derived mantle cell lymphoma 12 years after allogeneic transplantation

Donor-derived malignancy is a rare morbidity after allogeneic hematopoietic stem cell transplantation (HSCT), in which most previous cases have presented as acute leukemia or myelodysplastic syndrome. There have, however, been very few reports of donor-derived lymphoma. Here, we present a case of donor-derived mantle cell lymphoma 12 years after allogeneic HSCT, which was successfully treated with chemotherapy followed by pseudo-autologous HSCT (pASCT), i.e., an autologous HSC transplant following allogeneic HSCT in which the infused stem cell is considered to be derived from the donor cells. Although pASCT carries the risk of graft-versus-host disease (GVHD) due to the reinfusion of donor-derived peripheral blood cells, the present case did not develop GVHD without prophylaxis. The current case and a small number of previous reports suggest that the duration between allogeneic HSCT and pASCT may be important to the induction of immune tolerance, but further study in a larger number of cases is needed.