DISCOVERY OF A NOVEL, POTENTIAL FIRST-IN-CLASS MALT1 PROTEASE INHIBITOR FOR THE TREATMENT OF B CELL LYMPHOMAS

Development of Potent MALT1 Inhibitors Featuring a Novel "2-Thioxo-2,3-dihydrothiazolo[4,5-d]pyrimidin-7(6H)-one" Scaffold for the Treatment of B Cell Lymphoma

Mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) has emerged as a novel and promising therapeutic target for the treatment of lymphomas and autoimmune diseases. Herein, we reported a new class of MALT1 inhibitors featuring a novel "2-thioxo-2,3-dihydrothiazolo[4,5-d]pyrimidin-7(6H)-one" scaffold developed by structure-based drug design. Structure-activity relationship studies finally led to the discovery of MALT1 inhibitor 10m, which covalently and potently inhibited MALT1 protease with the IC50 value of 1.7 μM. 10m demonstrated potent and selective antiproliferative activity against ABC-DLBCL and powerful ability to induce HBL1 apoptosis. 10m also effectively downregulated the activities of MALT1 and its downstream signal pathways. Furthermore, 10m induced upregulation of mTOR and PI3K-Akt signals and exhibited a synergistic antitumor effect with Rapamycin in HBL1 cells. More importantly, 10m remarkably suppressed the tumor growth both in the implanted HBL1 and TMD8 xenograft models. Collectively, this work provides valuable MALT1 inhibitors with a distinct core structure.

Role of Specific B-Cell Receptor Antigens in Lymphomagenesis

The B-cell receptor (BCR) signaling pathway is a crucial pathway of B cells, both for their survival and for antigen-mediated activation, proliferation and differentiation. Its activation is also critical for the genesis of many lymphoma types. BCR-mediated lymphoma proliferation may be caused by activating BCR-pathway mutations and/or by active or tonic stimulation of the BCR. BCRs of lymphomas have frequently been described as polyreactive. In this review, the role of specific target antigens of the BCRs of lymphomas is highlighted. These antigens have been found to be restricted to specific lymphoma entities. The antigens can be of infectious origin, such as H. pylori in gastric MALT lymphoma or RpoC of M. catarrhalis in nodular lymphocyte predominant Hodgkin lymphoma, or they are autoantigens. Examples of such autoantigens are the BCR itself in chronic lymphocytic leukemia, LRPAP1 in mantle cell lymphoma, hyper-N-glycosylated SAMD14/neurabin-I in primary central nervous system lymphoma, hypo-phosphorylated ARS2 in diffuse large B-cell lymphoma, and hyper-phosphorylated SLP2, sumoylated HSP90 or saposin C in plasma cell dyscrasia. Notably, atypical posttranslational modifications are often responsible for the immunogenicity of many autoantigens. Possible therapeutic approaches evolving from these specific antigens are discussed.

Improving outcomes after autologous transplantation in relapsed/refractory Hodgkin lymphoma: a European expert perspective

Autologous stem cell transplantation (ASCT) is a well-established approach to treatment of patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL) recommended by both the European Society for Medical Oncology and the National Comprehensive Cancer Network based on the results from randomized controlled studies. However, a considerable number of patients who receive ASCT will progress/relapse and display suboptimal post-transplant outcomes. Over recent years, a number of different strategies have been assessed to improve post-ASCT outcomes and augment HL cure rates. These include use of pre- and post-ASCT salvage therapies and post-ASCT consolidative therapy, with the greatest benefits demonstrated by targeted therapies, such as brentuximab vedotin. However, adoption of these new approaches has been inconsistent across different centers and regions. In this article, we provide a European perspective on the available treatment options and likely future developments in the salvage and consolidation settings, with the aim to improve management of patients with HL who have a high risk of post-ASCT failure. CONCLUSIONS: We conclude that early intervention with post-ASCT consolidation improves outcomes in patients with R/R HL who require ASCT. Future approvals of targeted agents are expected to further improve outcomes and provide additional treatment options in the coming age of personalized medicine.