Overexpression of the key metabolic protein CPT1A defines mantle cell lymphoma patients with poor response to standard high-dose chemotherapy independent of MIPI and complement established highrisk factors.

The variable outcome to standard immunochemotherapy for mantle cell lymphoma (MCL) patients is a clinical challenge. Established risk factors, including high MCL International Prognostic Index (MIPI), high proliferation (Ki-67), non-classic (blastoid/pleomorphic) morphology, and mutated TP53, only partly identify patients in need of alternative treatment. Deepened understanding of biological factors that influence time to progression and relapse would allow for an improved stratification, and identification of novel targets for high-risk patients. We performed gene expression analyses to identify pathways and genes associated with outcome in a cohort of homogeneously treated patients. In addition to deregulated proliferation, we show that thermogenesis, fatty acid degradation and oxidative phosphorylation are altered in patients with poor survival, and that high expression of carnitine palmitoyltransferase 1A (CPT1A), an enzyme involved in fatty acid degradation, can specifically identify high-risk patients independent of the established high-risk factors. We suggest that complementary investigations of metabolism may increase the accuracy of patient stratification and that immunohistochemistry- based assessment of CPT1A can contribute to defining high-risk MCL.

Cost-Effectiveness of Brexucabtagene Autoleucel versus Best Supportive Care for the Treatment of Relapsed/Refractory Mantle Cell Lymphoma following Treatment with a Bruton's Tyrosine Kinase Inhibitor in Canada.

For patients with Mantle Cell Lymphoma (MCL), there is no recognized standard of care for relapsed/refractory (R/R) disease after treatment with a Bruton's tyrosine kinase inhibitor (BTKi). Brexucabtagene autoleucel (brexu-cel) represents a promising new treatment modality in MCL. We explored whether brexu-cel was cost-effective for the treatment of R/R MCL. We developed a partitioned survival mixture cure approach to model the costs and outcomes over a lifetime horizon. The clinical data were derived from the ZUMA-2 clinical trial. The costs were estimated from the publicly available Canadian databases, published oncology literature, and pan-Canadian Oncology Drug Review economic guidance reports. The health state utilities were sourced from the ibrutinib submission to the National Institute for Health and Care Excellence for R/R MCL and supplemented with values from the published oncology literature. In the base case over a lifetime horizon, brexu-cel generated an incremental 9.56 life-years and an additional 7.03 quality-adjusted life-years compared to BSC, while associated with CAD 621,933 in additional costs. The resultant incremental cost-utility ratio was CAD 88,503 per QALY gained compared with BSC. Based on this analysis, we found brexu-cel to be a cost-effective use of healthcare resources relative to BSC for treatment of adult patients with R/R MCL previously treated with a BTKi in Canada, though additional research is needed to confirm these results using longer follow-up data.

Oxaliplatin before autologous transplantation in combination with high-dose cytarabine and rituximab provides longer disease control than cisplatin or carboplatin in patients with mantle-cell lymphoma: results from the LyMA prospective trial.

LyMA trial has demonstrated the benefit of rituximab maintenance after autologous stem cell transplantation (ASCT) in previously untreated mantle-cell lymphoma patients (MCL). Induction consisted of four courses of R-DHAP (rituximab, dexamethasone, high-dose cytarabine, and platinum derivative). The platinum derivative (PD) choice was free: R-DHA-cisplatin, R-DHA-carboplatin, or R-DHA-oxaliplatin. We investigated the prognostic impact of each PD. PFS and OS calculated from inclusion and investigated in an intention-to-treat (ITT) (= 298) and per-protocol analyses (PP) (n = 227). R-DHACis, R-DHACa, or R-DHAOx were used at first cycle in 184, 76, and 38 patients, respectively. Overall, 71 patients (59 in the R-DHACis) required a change in PD, mainly because of PD toxicity. In ITT-analysis, PFS in the R-DHACis and R-DHACa groups were similar (4-year PFS of 65%), while R-DHAOx had a better PFS (4-year PFS of 65% versus 86.5%, respectively, HR = 0.44, p = 0.02). The 4-year OS was 92% for R-DHAOx versus 75.9% for R-DHACis/DHACa (HR = 0.37, p = 0.03). Similar results were yielded in the PP analysis. Low MIPI and R-DHAOx were independent favorable prognostic markers for both PFS (HR = 0.44, p = 0.035) and OS (HR = 0.36, p = 0.045). In vitro and in silico analyses confirmed that oxaliplatin has an anti-MCL cytotoxic effect that differs from that of other PD. R-DHAOx before ASCT provides better outcome in transplantation eligible young MCL patients.

Pirtobrutinib in relapsed or refractory B-cell malignancies (BRUIN): a phase 1/2 study.

BACKGROUND: Covalent Bruton's tyrosine kinase (BTK) inhibitors are efficacious in multiple B-cell malignancies, but patients discontinue these agents due to resistance and intolerance. We evaluated the safety and efficacy of pirtobrutinib (working name; formerly known as LOXO-305), a highly selective, reversible BTK inhibitor, in these patients. METHODS: Patients with previously treated B-cell malignancies were enrolled in a first-in-human, multicentre, open-label, phase 1/2 trial of the BTK inhibitor pirtobrutinib. The primary endpoint was the maximum tolerated dose (phase 1) and overall response rate (ORR; phase 2). This trial is registered with ClinicalTrials.gov, NCT03740529. FINDINGS: 323 patients were treated with pirtobrutinib across seven dose levels (25 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, and 300 mg once per day) with linear dose-proportional exposures. No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. The recommended phase 2 dose was 200 mg daily. Adverse events in at least 10% of 323 patients were fatigue (65 [20%]), diarrhoea (55 [17%]), and contusion (42 [13%]). The most common adverse event of grade 3 or higher was neutropenia (32 [10%]). There was no correlation between pirtobrutinib exposure and the frequency of grade 3 treatment-related adverse events. Grade 3 atrial fibrillation or flutter was not observed, and grade 3 haemorrhage was observed in one patient in the setting of mechanical trauma. Five (1%) patients discontinued treatment due to a treatment-related adverse event. In 121 efficacy evaluable patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) treated with a previous covalent BTK inhibitor (median previous lines of treatment 4), the ORR with pirtobrutinib was 62% (95% CI 53-71). The ORR was similar in CLL patients with previous covalent BTK inhibitor resistance (53 [67%] of 79), covalent BTK inhibitor intolerance (22 [52%] of 42), BTK C481-mutant (17 [71%] of 24) and BTK wild-type (43 [66%] of 65) disease. In 52 efficacy evaluable patients with mantle cell lymphoma (MCL) previously treated with covalent BTK inhibitors, the ORR was 52% (95% CI 38-66). Of 117 patients with CLL, SLL, or MCL who responded, all but eight remain progression-free to date. INTERPRETATION: Pirtobrutinib was safe and active in multiple B-cell malignancies, including patients previously treated with covalent BTK inhibitors. Pirtobrutinib might address a growing unmet need for alternative therapies for these patients. FUNDING: Loxo Oncology.

Life-threatening disseminated enterovirus infection during combined rituximab and ibrutinib maintenance treatment for mantle cell lymphoma: a case report.

BACKGROUND: Rituximab is a well-established component of treatment regimens for B-cell non-Hodgkin lymphoma. Rituximab binds the CD20 antigen on the surface of B lymphocytes, causing an enhanced clearance of malignant and benign B cells. Thus, rituximab leads to depletion of normal B lymphocytes as well, which can cause substantial immunodeficiency. Ibrutinib inhibits the Bruton tyrosine kinase and thereby B-cell activity. It is used for the treatment of different B-lymphocyte malignancies, such as mantle cell lymphoma. Recently, the combination of both drugs has been tested in various clinical scenarios. CASE PRESENTATION: We present a case of disseminated enterovirus infection resulting from combined rituximab and ibrutinib maintenance treatment in a 57-year-old Caucasian patient. with mantle cell lymphoma. Initially presenting with myositis symptoms, further diagnostic investigation revealed myocarditis, enteritis, myeloencephalitis, and hepatitis. These organ manifestations led to potentially life-threatening complications such as rhabdomyolysis, delirium, and heart rhythm disturbances. After treatment with high-dose intravenous immunoglobulins, virus clearance was achieved and organ functions could be restored. CONCLUSIONS: This case emphasizes the risk of combined therapy with rituximab/ibrutinib for severe immune-related side effects with the necessity of continuous patient monitoring. High-dose intravenous therapy should be considered as treatment for severe enterovirus infection. In severe enterovirus infections, we recommend subtyping for the development of efficient preventive and therapeutic strategies.

Management of Mantle Cell Lymphoma in the Era of Novel Oral Agents.

Objectives: To discuss (1) recent and emerging data for pharmacological management of untreated and relapsed/refractory (R/R) mantle cell lymphoma (MCL) with agents approved in the United States, (2) important considerations for toxicity monitoring and management, and (3) preliminary data and ongoing studies for agents in MCL-specific clinical trials. Data Sources: PubMed/MEDLINE, EMBASE, Google Scholar, product labeling, National Comprehensive Cancer Network, American Cancer Society, and ClinicalTrials.gov were searched for studies published between January 1, 2017, and January 31, 2020, and key historical trials. Study Selection and Data Extraction: Relevant studies conducted in humans and selected supporting preclinical data were reviewed. Data Synthesis: MCL is a rare but usually aggressive non-Hodgkin lymphoma that most commonly affects the older population. Traditionally, the treatment of MCL has been determined based on transplant eligibility. Newer data suggest that more tolerable frontline therapy may produce outcomes similar to intensive historical induction regimens, possibly precluding fewer patients from autologous stem cell transplant and producing better long-term outcomes in transplant-ineligible patients. In the R/R setting, novel regimens are improving outcomes and changing the landscape of treatment. Relevance to Patient Care and Clinical Practice: This review summarizes and discusses recent and emerging data for management of newly diagnosed and R/R MCL; key supportive care considerations for agents are also discussed. Conclusions: Recent study results are changing management of MCL. Although these data have complicated the picture of regimen selection, increasingly effective and tolerable therapy and additional anticipated data point to a brighter future for patients with MCL.

Drug Repurposing Screen Identifies Novel Classes of Drugs with Anticancer Activity in Mantle Cell Lymphoma.

AIM AND OBJECTIVE: Mantle Cell Lymphoma (MCL) is typically an aggressive and rare disease with poor prognosis, therefore new effective therapeutics are urgently needed. Drug repurposing for cancer treatment is becoming increasingly more attractive as an alternative approach to discover clinically approved drugs that demonstrate antineoplastic effect. The objective of this study was to screen an approved drug library and identify candidate compounds with an antineoplastic effect in MCL cells using High-Throughput Screening (HTS) technique. MATERIALS AND METHODS: Using the HTS technique, nearly 3,800 clinically approved drugs and drug candidates were screened in Jeko and Mino MCL cell lines. We also demonstrated the selectivity window of the candidate compounds in six normal cell lines. Further validations were performed in caspase-3/7 apoptosis assay and three-dimensional (3D) multicellular aggregates model using Z138 cell line. RESULTS: We identified 98 compounds showing >50% inhibition in either MCL cell line screened, they were distributed across eight unique therapeutic categories and have different mechanisms of action (MOA). We selected alisertib, carfilzomib, pracinostat and YM155 for further validation based on their antiproliferative activity in two MCL cell lines, selectivity to normal cell lines, and drug developing stages in terms of clinical research. Alisertib and carfilzomib showed antiproliferative effect on MCL cell with EC50 = 6 nM and >100-fold selectivity to normal cell lines, especially for alisertib which demonstrated >1000-fold selectivity to 5 out of 6 normal cell lines. Pracinostat and YM155 had potency of 11 and 12 nM in MCL cell with >20-fold selectivity to normal cell lines. All four compounds had been tested in caspase-dependent apoptosis assay. We further validated and demonstrated their anti-MCL effect on cell proliferation and (3D) multicellular aggregates model using Z138 cell line. CONCLUSION: This is the first study to examine such a large library of clinically approved compounds for the identification of novel drug candidates for MCL treatment, the results could be rapidly translated into clinical practice in patients with MCL.

Dihydrocelastrol exerts potent antitumor activity in mantle cell lymphoma cells via dual inhibition of mTORC1 and mTORC2.

Mantle cell lymphoma (MCL) is a distinct and highly aggressive subtype of B-cell non-Hodgkin lymphoma. Dihydrocelastrol (DHCE) is a dihydro-analog of celastrol, which is isolated from the traditional Chinese medicinal plant Tripterygium wilfordii. The present study aimed to investigate the effects of DHCE treatment on MCL cells, and to determine the mechanism underlying its potent antitumor activity in vitro and in vivo using the Cell Counting kit-8 assay, clonogenic assay, apoptosis assay, cell cycle analysis, immunofluorescence staining, western blotting and tumor xenograft models. The results demonstrated that DHCE treatment exerted minimal cytotoxic effects on normal cells, but markedly suppressed MCL cell proliferation by inducing G0/G1 phase cell cycle arrest, and inhibited MCL cell viability by stimulating apoptosis via extrinsic and intrinsic pathways. In addition, the results revealed that DHCE suppressed cell growth and proliferation by inhibiting mammalian target of rapamycin complex (mTORC)1-mediated phosphorylation of ribosomal protein S6 kinase and eukaryotic initiation factor 4E binding protein. Simultaneously, DHCE induced apoptosis and inhibited cell survival by suppressing mTORC2-mediated phosphorylation of protein kinase B and nuclear factor-κB activity. In addition to in vitro findings, DHCE treatment reduced the MCL tumor burden in a xenograft mouse model, without indications of toxicity. Furthermore, combined treatment with DHCE and bortezomib, a proteasome inhibitor, induced a synergistic cytotoxic effect on MCL cells. These findings indicated that DHCE may have the potential to serve as a novel therapeutic agent for the treatment of MCL through dually inhibiting mTORC1 and mTORC2.

Implementation of a Model-Based Design in a Phase Ib Study of Combined Targeted Agents.

In recent years, investigators have recognized the rigidity of single-agent, safety-only, traditional designs, rendering them ineffective for conducting contemporary early-phase clinical trials, such as those involving combinations and/or biological agents. Novel approaches are required to address these research questions, such as those posed in trials involving targeted therapies. We describe the implementation of a model-based design for identifying an optimal treatment combination, defined by low toxicity and high efficacy, in an early-phase trial evaluating a combination of two oral targeted inhibitors in relapsed/refractory mantle cell lymphoma. Operating characteristics demonstrate the ability of the method to effectively recommend optimal combinations in a high percentage of trials with reasonable sample sizes. The proposed design is a practical, early-phase, adaptive method for use with combined targeted therapies. This design can be applied more broadly to early-phase combination studies, as it was used in an ongoing study of a melanoma helper peptide vaccine plus novel adjuvant combinations. Clin Cancer Res; 23(23); 7158-64. ©2017 AACR.

Eficacia y seguridad de ibrutinib en el tratamiento de pacientes con diagnóstico de linfoma de células del manto, con al menos dos líneas de tratamiento previo / Efficacy and safety of ibrutinib in the treatment of patients diagnosed with mantle cell lymphoma, with at least two lines of previous treatment

INTRODUCCIÓN: El presente dictamen expone la evaluación de tecnología de la eficacia y seguridad de del uso de ibrutinib en el tratamiento de pacientes con diagnóstico de linfoma de células del manto. El linfoma de células del manto (LCM) es un tipo muy agresivo de linfoma no-Hodgkin que se origina por la malignización de los linfocitos B en el margen externo del folículo de un ganglio linfático o zona del manto y se caracteriza por la translocación cromosomal t(11,14) y la sobre-expresión de la ciclina D1. El pronóstico de los pacientes con LCM es malo siendo potencialmente una enfermedad incurable. Sin embargo, existe una gran variabilidad clínica al respecto, encontrándose desde casos con una evolución muy agresiva y una sobrevida muy corta, hasta casos con una evolución crónica e indolente, en los cuales la sobrevida media se ha estimado en 3-4 años. El tratamiento de los pacientes con LCM incluye diferentes regímenes de inmuno-quimioterapia, por lo general a base de rituximab. Si bien existen altas tasas de respuesta al tratamiento inicial, la gran mayoría de pacientes recae y muere a causa de la enfermedad. Es por ello que surge la necesidad de contar con alternativas de tratamiento especialmente para aquellos pacientes con LCM que han progresado a dos o más líneas de tratamiento con rituximab. TECNOLOGIA SANITARIA DE INTERÉS: Ibrutinib (Imbruvica®, Janssen), un inhibidor covalente de primera generación de la tirosina quinasa de Bruton (BTK, por sus siglas en inglés), es una molécula pequeña que se une de manera irreversible al residuo 481 de cisteína en el dominio de la quinasa de la tirosina quinasa de Bruton de las células B. Adicionalmente, ibrutinib también se puede unir a otros dominios de quinasa que contienen un residuo de cisteína homólogo, tales como HER2, BLK y JAK3 entre otros. El linfoma no-Hodgkin de células del manto es un tipo de neoplasia de células B. La quinasa de Bruton se encuentra por debajo de la cascada de señalización del receptor de las células B. La señal enviada por el receptor de dichas células, ya sea dependiente o independiente de antígenos, es considerada una de los principales mecanismos detrás de la progresión de este tipo de neoplasias, ya que juega un rol critico en la supervivencia y proliferación de las células B (15) . Así este actúa inhibiendo la proliferación de los linfocitos B y acelera la muerte de las células tumorales. El producto farmacéutico ibrutinib es elaborado, patentado y comercializado originalmente por Pharmacyclics Inc. y luego por el laboratorio Janssen como Imbruvica®, se encuentra disponible en presentación de cápsulas de 140 mg. METODOLOGIA: Se realizó una búsqueda de la literatura con respecto a la eficacia y seguridad del uso de ibrutinib para el tratamiento de LCM en pacientes que han progresado a más de dos líneas de tratamiento previo. Esta búsqueda se realizó utilizando las bases de datos de MEDLINE, EMBASE, SCOPUS, WEB OF SCIENCE, CINAHL, COCHRANE y TRIP DATABASE. Adicionalmente, se hizo una búsqueda dentro de la información generada por las principales agencias de tecnologías sanitarias que realizan revisiones sistemáticas (RS), evaluación de tecnologías sanitarias (ETS) y guías de práctica clínica (GPC). Esta búsqueda se complementó revisando publicaciones de grupos dedicados a la educación, investigación y mejora de la práctica clínica oncológica dentro de América y Europa, como The National Comprehensive Cancer Network (NCCN), The American Society of Clinical Oncology (ASCO) y The European Society of Medical Oncology (ESMO). Por último, se completó la búsqueda ingresando a la página web www.clinicaltrials.gov, lo cual permitió identificar ensayos clínicos en elaboración o que aún no publicados, con la finalidad de tener conocimiento de futuras posibles publicaciones, así como de disminuir el riesgo de sesgo de publicación. RESULTADOS: El presente dictamen recoge la evidencia científica publicada hasta noviembre 2016 en relación al uso de ibrutinib en pacientes con LCM que han recibido más de dos líneas de tratamiento, la cual incluye dos GPC, dos ETS, y un ensayo clínico fase III (RAY). La principal evidencia utilizada en las GPC es el ensayo de fase II (PCYC1104), el cual no es incluido en el presente dictamen por no ser un ensayo controlado ni aleatorizado e incluir una proporción considerable (aproximadamente 40%) de pacientes que recayeron a regímenes asociados a bortezomib y no solo rituximab. Por otro lado, el ensayo clínico de fase III (RAY), incluido en el presente dictamen, es considerado la principal evidencia de las ETS revisadas. En dicho ensayo se compara ibrutinib con temsirolimus para el tratamiento de LCM en pacientes refractarios o con recaídas a tratamientos previos. Sin embargo, el comparador utilizado (i.e., temsirolimus) es distinto al de interés del presente dictamen (i.e., placebo o mejor terapia de soporte). Temsirolimus no está aprobado dentro EsSalud, por lo tanto, no puede ser considerado como un posible comparador dentro de la institución, haciendo que la evidencia proveniente de este ensayo sea indirecta. Así, en este ensayo se encontró diferencias en la sobrevida libre de progresión, mas no en la sobrevida global. También se encontraron diferencias en desenlaces relacionados a calidad de vida y eventos adversos. Sin embargo, las diferencias de estos últimos presentan un elevado riesgo de sesgo. Por lo tanto, debido a que no se encontró diferencia en el desenlace duro de sobrevida global, que los desenlaces de calidad de vida y eventos adversos tienen un alto riesgo de sesgo, y a que el comparador utilizado (i.e., temsirolimus) podría no ser el más apropiado por su perfil de toxicidad; a la fecha no existe claridad en relación a la eficacia y seguridad de ibrutinib como tratamiento para LCM en enfermedad progresiva, refractaria, o con recaída, a más de dos líneas de tratamiento. CONCLUSIÓN: El Instituto de Evaluación de Tecnologías en Salud e Investigación (IETSI) no aprueba el uso de ibrutinib para el tratamiento de LCM en pacientes con al menos dos líneas de tratamiento.

[Anti-tumor effects of 13-cis-retinoic acid combined with interferon α-2b in animal model of mantle cell lymphoma].

Objective: To determine the anti-tumor effects of 13-cis-retinoic acid (13cRA) combined with interferonα-2b (IFNα-2b) in mantle cell lymphoma (MCL) animal model. Methods: The animal model of MCL was established by introducing Jeko-1 cell line into severe combined immunodeficiency disease mice. The successfully tumor-developed mice were assigned to different groups treated with negative control group (solvents), 13cRA (high dose: 200mg/kg; middle dose: 100mg/kg; low dose: 50 mg/kg) alone, IFNα-2b alone or combination of different dose of 13cRA with IFNα-2b, and positive control group (bortezomib, rituximab, cyclophosphamide), respectively. Variations of tumor volume were observed regularly. The relative tumor proliferation rate and tumor inhibition rate were calculated. Immunohistochemistry stain was used to detect the Ki-67 expression and TUNEL was applied to measure the apoptosis of tumor cells. Furthermore, the levels of Cyclin D1, caspase 9 and Rb protein were measured by Western-blot method. Results: ① The relative tumor proliferation rates (T/C%)were 30%, 37%, 32% and 33% in middle dose, high dose groups of 13cRA as well as their combination with IFN α-2b, respectively. ② Comparing with the negative control, both 13cRA at different doses and its combination with IFNα-2b remarkably inhibited the tumor growth (P<0.05), while no statistic significance existed in different dose group of 13cRA. IFN-α 2b alone didn't demonstrate the tumor-inhibition effects (P>0.05). Middle dose of 13cRA and its combination with IFN-α-2b demonstrated relatively high tumor-inhibition effects (59.2% and 62.6% respectively), which were similar to the effects in positive control (69.4%). ③ There was no statistic difference of Ki-67 in each experimental group. ④ Comparing with negative control group, all doses of 13cRA and their combinations with IFNα-2b remarkably increased the apoptosis (P<0.05), similar to the positive control group (P>0.05). However, IFNα-2b alone didn' t promote the apoptosis of tumor tissue (P=0.098). ⑤ Comparing with negative control group, IFNα-2b combined with each dose of 13cRA significantly decreased the levels of cycling D1 and procaspase-9, while increased the level of cleaved caspase-9 (P<0.05), which were similar to the positive control group (P>0.05). Nevertheless, 13cRA alone didn't demonstrate such effects. Conclusion: In the MCL animal model, IFNα-2b alone showed no effects, but combined with IFNα-2b, 13cRA displayed anti-tumor effects at different doses. The anti-tumor mechanism of 13cRA combined with IFNα-2b was probably down-regulation of the cyclin D1 expression, inhibition of cell proliferation and induction of apoptosis by activating caspase-9.

Mantle Cell Lymphoma.

Mantle cell lymphoma (MCL) is an uncommon subtype of non-Hodgkin lymphoma previously considered to have a poor prognosis. Large gains were made in the first decade of the new century when clinical trials established the importance of high-dose therapy and autologous stem-cell rescue and high-dose cytarabine in younger patients and the benefits of maintenance rituximab and bendamustine in older patients. In particular, greater depth of understanding of the molecular pathophysiology of MCL has resulted in an explosion of specifically targeted new efficacious agents. In particular, agents recently approved by the Food and Drug Administration include the proteasome inhibitor bortezomib, immunomodulator lenalidomide, and Bruton's tyrosine kinase inhibitor ibrutinib. We review recent advances in the understanding of MCL biology and outline our recommended approach to therapy, including choice of chemoimmunotherapy, the role of stem-cell transplantation, and mechanism-based targeted therapies, on the basis of a synthesis of the data from published clinical trials.

Ibrutinib for mantle cell lymphoma.

Mantle cell lymphoma (MCL) is a rare and aggressive form of non-Hodgkin lymphoma. Ibrutinib is a first-in-class, oral inhibitor of Bruton's tyrosine kinase which acts by downstream inhibition of the B-cell receptor. Early clinical trials have demonstrated excellent tolerability and a modest side-effect profile in relapsed/refractory MCL. Although the majority of disease responses are partial, efficacy data are impressive with more than two-thirds of patients demonstrating a durable response. This article focuses on all aspects of ibrutinib in the context of MCL, including a summary of the basic pharmacology and pharmacokinetics; a review of the safety and efficacy data published to date and a discussion of the future implications in MCL.

Activity of ibrutinib in mantle cell lymphoma patients with central nervous system relapse.

The risk of central nervous system (CNS) dissemination in mantle cell lymphoma (MCL) is low and occurs late in the course of the disease. However, prognosis in such cases remains extremely poor despite high-dose antimetabolite chemotherapy. Among novel drugs used to treat relapsing MCL patients, ibrutinib, an oral inhibitor of Bruton tyrosine kinase, shows great promise. Here we report the clinical observation of 3 MCL patients with symptomatic CNS relapse treated with single-agent ibrutinib. All 3 patients had dramatic and rapid responses with almost immediate recovery from symptoms. We also confirmed that ibrutinib crosses the blood-brain barrier with parallel pharmacokinetic analyses in plasma and cerebrospinal fluid using a validated LC-MS/MS method. All responses were ongoing after 2 months to 1 year of follow-up.

Ofatumumab Exhibits Enhanced In Vitro and In Vivo Activity Compared to Rituximab in Preclinical Models of Mantle Cell Lymphoma.

PURPOSE: Mantle cell lymphoma (MCL) is a mature B-cell lymphoma considered to be incurable with current treatments, including first-line rituximab in combination with multiagent chemotherapy and for those eligible, high-dose chemotherapy and stem cell support or rituximab maintenance. On the other hand, achieving a complete remission by high-sensitive flow cytometry is associated with prolonged duration of remission, stressing the need to develop and/or incorporate novel agents into the management of MCL. To this end, we examined the activity of ofatumumab, an anti-CD20 monoclonal antibody with distinct binding and immunologic properties compared to rituximab, in MCL preclinical models. EXPERIMENTAL DESIGN: MCL cells were labeled with (51)Cr before incubation with rituximab or ofatumumab (10 µg/mL) plus human serum or effector cells. (51)Cr-release was measured and the percentage of lysis was calculated. Surface CD20, CD55, and CD59 were measured by Imagestream analysis. SCID mice inoculated subcutaneously with Z138 cells were assigned to control versus four doses of ofatumumab or rituximab (10 mg/kg/dose). RESULTS: Ofatumumab exhibited enhanced in vitro complement-dependent cytotoxicity activity compared with rituximab in MCL cell lines, despite a high degree of in vitro resistance to rituximab associated with low CD20 levels and/or high expression of complement inhibitory proteins. Ofatumumab also delayed tumor progression and prolonged survival in a murine model of MCL. CONCLUSIONS: Our results demonstrate that ofatumumab is more effective than rituximab in MCL preclinical models, including in the presence of rituximab resistance, and support the clinical investigation of ofatumumab in combination with standard systemic chemotherapy in MCL (NCT01527149).

Ibrutinib for the treatment of mantle cell lymphoma.

Ibrutinib (PCI-32765)--a potent, covalent inhibitor of Bruton tyrosine kinase (BTK), an important kinase in the B-cell receptor signaling pathway--was recently approved by the FDA for the treatment of relapsed or refractory mantle cell lymphoma (MCL). The drug was granted accelerated approval based on the findings of an international, multicenter, single-arm phase II study that enrolled patients with relapsed or refractory MCL. In the study, ibrutinib (560 mg daily) was well tolerated as a single agent and resulted in an overall response rate of 68% and an estimated median response duration of 17.5 months. Ibrutinib's response rate and duration of response compare favorably with those for other novel agents approved for the treatment of relapsed or refractory MCL, while being less toxic than most chemotherapy or chemoimmunotherapy regimens. Ibrutinib is currently being studied in combination with chemoimmunotherapy, monoclonal antibody therapy, and novel agents in both the initial and the relapsed/refractory treatment settings. We review the mechanism of action, preclinical and clinical development, and the role of ibrutinib in the context of other available treatments.

Oral arsenic trioxide-based regimen as salvage treatment for relapsed or refractory mantle cell lymphoma.

BACKGROUND: Mantle cell lymphoma (MCL) is aggressive, and relapsed/refractory disease has poor outcomes. PATIENTS AND METHODS: Thirty-nine patients (men = 34, women = 5) at 64 (41-82) years of age with relapsed/refractory MCL, ineligible for high-dose chemotherapy and had received 2 (1-5) prior regimens, were treated with a continuous oral regimen, comprising oral arsenic trioxide (oral-As2O3), chlorambucil and ascorbic acid. RESULTS: Overall response rate was 49% (complete response, CR = 28%; partial response, PR = 21%). Only grade 1/2 toxicities were observed (hematologic: 56%, hepatic: 8%). Response was maintained in 11 patients (CR = 8; PR = 3), after a median of 24 (2-108) months. Independent prognostic factors for response were increased lactate dehydrogenase (P = 0.04) and unfavorable MCL international prognostic index (P = 0.04). At a median follow-up of 21 (1-118) months, the median progression-free survival (PFS) was 16 months, and overall survival (OS) 38 months. Independent prognostic factors for PFS were female gender (P = 0.002), and Eastern Cooperative Oncology Group (ECOG) performance score of 2 (P = 0.009). Independent prognostic factors for OS were female gender (P < 0.001), ECOG performance score of 2 (P = 0.03), non-response (P < 0.001), and disease progression after initial response (P = 0.05). CONCLUSION: An oral regimen of oral-As2O3, chlorambucil and ascorbic acid was active with minimal toxicity in relapsed/refractory MCL, achieving durable responses in ∼30% of cases.

Bruton tyrosine kinase inhibitor ibrutinib (PCI-32765).

Over the past 3 years, ibrutinib (PCI-32765) has emerged as a breakthrough in targeted therapy for patients with certain types of B cell malignancies. Early stage clinical trials found ibrutinib to be particularly active in chronic lymphocytic leukemia (CLL) and mantle cell lymphoma (MCL), providing the rationale for ongoing phase 3 trials. In contrast to conventional chemo-immunotherapy, ibrutinib is not myelosuppressive, and responses are not affected by disease features that predict failure to respond to or short remission durations after chemo-immunotherapy, such as del17p. In CLL, ibrutinib characteristically causes an early redistribution of tissue-resident CLL cells into the blood, with rapid resolution of enlarged lymph nodes, along with a surge in lymphocytosis. Later, after weeks to months of continuous ibrutinib therapy, the growth- and survival-inhibitory activities of ibrutinib result in the normalization of lymphocyte counts and remissions in a majority of patients. This review discusses the discovery, preclinical and clinical development of ibrutinib, its pathophysiological basis, and outlines perspectives for future use of ibrutinib.