Abstract C127: Discovery of AUR-112, a novel MALT1 protease inhibitor for the treatement of B cell lymphomas

Abstract MALT1 is a key regulator of antigen receptor signaling in B and T cells. MALT1 partners with BCL10 and CARMA1 to form the CBM complex in which protease activity of MALT1 cleaves the negative regulators (A20, CYLD, RelB) leading to activation of canonical NF-kB pathway. Constitutive activation of NF-kB signaling is a key driver in B-cell lymphomas including diffuse large B-cell lymphomas (DLBCL). Therapeutic targeting of MALT1 protease activity can therefore be a useful approach for the treatment of B-cell lymphomas with dysregulated NF-kB signaling. We sought to discover and develop MALT1 inhibitors with the “best-in-class” profile with an emphasis on lowering plasma protein binding (PPB) to achieve improved pharmacological outcome. After extensive SAR efforts utilizing various computational methods, AUR-112 has been identified as a potential development candidate. The allosteric inhibitor AUR-112 exhibited potent and selective inhibition of MALT1 protease activity in both biochemical and cellular assays. Inhibition of MALT1 correlated with potent antiproliferative activity in an ABC-DLBCL cell line. The mechanistic activity of AUR-112 is supported by the inhibition of IL-10 in a cell line and IL-2 in human whole blood. Consistent with our objective, AUR112 showed low plasma protein binding across multiple species, which translated to greater potency in whole blood compared to published MALT1 inhibitors, positioning it as a best-in-class contender. AUR-112 has excellent oral bioavailability across species and exhibited desirable selectivity profile in kinase, protease and CEREP safety screen panels. Oral administration of AUR-112 led to dose dependent anti-tumor activity including durable tumor regression in cell line and patient derived xenograft models. Treatment with AUR-112 led to potent pharmacodynamic modulation in xenograft models as measured by significant and sustained reduction in serum IL-10 levels that correlated with the compelling efficacy. AUR-112 also demonstrated dose dependent inhibition of T-reg cells in vitro and in vivo supporting the immune modulatory role of MALT1 inhibition. AUR-112 is identified as a development candidate with potentially best-in-class physico-chemical properties resulting in a high free fraction for treatment of ABC-DLBCL patients. IND enabling studies are currently ongoing to support the clinical development of AUR-112. Citation Format: Wesley Roy Balasubramanian, Sammeta Srinivasa Raju, Vasantha K.Y, Archana Bhumi Reddy, Janith Mary Maben, Sandeep Sadashiv Patil, Raghavendra N.R, Kiran Aithal B, Charamanna K.B, Dinesh Chikkanna, Kavitha Nellore, Samiulla D.S, Girish Daginakatte, Shekar Chelur, Murali Ramachandra, Susanta Samajdar. Discovery of AUR-112, a novel MALT1 protease inhibitor for the treatement of B cell lymphomas [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C127.