Session: 625. Lymphoma: Pre-Clinical—Chemotherapy and Biologic Agents: Poster I
Hematology Disease Topics & Pathways:
Diseases, Marginal Zone Lymphoma, Non-Biological, cell division, Mantle Cell Lymphoma, Therapies, Combinations, cell regulation, Non-Hodgkin Lymphoma, DLBCL, B-Cell Lymphoma, Biological Processes, Lymphoid Malignancies, pharmacology, inflammation, pathogenesis, pathways, signal transduction
Results: We have identified novel small molecule MALT1 inhibitors using our proprietary physics-based Free Energy Perturbation (FEP+) modeling technology. Our compounds show potent (sub nM) inhibition of MALT1 enzymatic activity, as well as high binding affinity (sub nM) to MALT1 protein measured by Surface Plasmon Resonance (SPR). BCL10 is a binding partner of MALT1 that is cleaved by MALT1 at the C-terminus. Our inhibitors were efficacious in a target engagement assay showing prevention of BCL10 cleavage in Activated B-cell (ABC) subtype of diffuse large B cell lymphoma (DLBCL) cell lines OCI-LY3 and OCI-LY10, which are Bruton tyrosine kinase (BTK) inhibitor ibrutinib-resistant and -responsive respectively. Our compounds are potent inhibitors of IL10 secretion in both OCI-LY3 and OCI-LY10 cells, which is consistent with the inhibition of NF-κB signaling. We also examined the effect of our MALT1 inhibitors on ABC-DLBCL cell proliferation. Our inhibitors demonstrated potent anti-proliferative effects in both OCI-LY3 and OCI-LY10 cell lines, as well as synergistic effects with ibrutinib in a BTKi sensitive ABC-DLBCL cell panel. Examinations of a protease panel and off-target safety screening panel, as well as in vivo high dose tolerability study showed our compound had excellent selectivity and significant safety margin. Plasma IL10 and tumor BCL10 have been identified as robust PD markers in PK/PD studies in both OCI-LY3 and OCI-LY10 tumor bearing mice. Dose-dependent tumor growth inhibition was observed after 3 weeks of treatment in OCI-LY3 xenograft model, with efficacy also observed in combination with venetoclax.
Ongoing work: We are continuing to explore the synergistic effects of our compounds with BTK inhibitors in B-cell lymphoma mouse models. Preliminary data showed potent inhibition of IL-2 secretion in Jurkat cells from our compound treatment. Additional studies are ongoing to elucidate the role of MALT1 inhibition in Treg as well as Teffector cells in vitro and in vivo. Refinement of the current inhibitor series, using co-crystal structures, is in progress in preparation for further development of optimized molecules.
Conclusion and Future Plans: We have identified novel potent MALT1 protease small molecule inhibitors that are efficacious in the in vitro B-cell lymphoma cell proliferation assays and in the in vivo B-cell lymphoma xenograft model. Our data suggest that targeting MALT1 may expand therapy options for patients with selected B-cell lymphomas, such as ABC-DLBCL. Our work provided insight into the anti-tumor efficacy of our inhibitors in B-cell lymphomas as single agent, and ongoing work will continue to assess the potential combination with BTKi to overcome drug-induced resistance in patients with relapsed/refractory B-cell lymphoma.
Disclosures: Yin: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Zhe: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Placzek: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Trzoss: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Krilov: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Feng: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Lawrenz: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Pelletier: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Lai: Triplet Therapeutics: Current Employment, Current equity holder in private company. Bell: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Calkins: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Grimes: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Tang: Schrodinger: Current Employment, Current equity holder in publicly-traded company. McRobb: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Gerasyuto: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Feher: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Mondal: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Jensen: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Wright: Schrodinger: Current Employment, Current equity holder in publicly-traded company. Akinsanya: Schrodinger: Current Employment, Current equity holder in publicly-traded company.
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