Abstract 3646: Novel IRAK-4 inhibitors exhibit highly potent anti-proliferative activity in DLBCL cell lines with activating MYD88 L265P mutation

Abstract

Abstract Interleukin-1 Receptor Associated Kinase-4 (IRAK-4) is a serine/threonine protein kinase belonging to tyrosine like kinase (TLK) family. IRAK-4 is one of the important signalling components downstream of IL-1/Toll family of receptors (IL-1R, IL-18R, IL-33R, Toll-like receptors). Recent studies have reported occurrence of oncogenic mutations in MYD88 in 30% of ABC diffuse large B cell lymphomas (ABC DLBCL) and 90% of Waldenstrom's macroglobulinemia (WM). Most of ABC DLBCLs have a single amino acid substitution of proline for the leucine at position 265 (L265P) in the TIR domain of MYD88 protein resulting in constitutive activation of IRAK-4. Thus, IRAK4 is an attractive therapeutic target for the treatment of B-cell lymphomas with activating MYD88 L265P mutation. We have designed, synthesized and tested small molecule IRAK-4 inhibitors based on hits originating from Aurigene’ s compound library. These novel compounds were profiled for IRAK4 kinase inhibition, anti-proliferative activity, kinase selectivity, and drug-like properties. Furthermore, selected compounds were tested in a proliferation assay and pIRAK1 mechanistic assay using ABC-DLBCL cell lines with activating MYD88 L265P mutation, OCI-lLy10 and OCI-lLy3. We have identified a series of novel bicyclic heterocycles as potent inhibitors of IRAK-4. Aurigene Lead compound exhibited potent inhibitory activity for IRAK-4 with an IC50 of 3nM in biochemical assay. Aurigene Lead compound inhibited pIRAK1 levels, and proliferation of OCI-Ly3 and OCI-Ly10 cells with an IC501of 132nM and 52nM respectively. To the best of our knowledge, Aurigene Lead compound represents the most potent IRAK4 inhibitor reported for target modulation and anti-proliferative activity in DLBCL cell lines with activating MYD88 L265P mutation. Aurigene Lead compound has good oral pharmacokinetic profile in mice and has demonstrated excellent pharmacodynamic effect in an in vivo LPS induced TNF-α model with an ED50 of 3.8 mg/Kg in mice. Preliminary in vitro tox studies indicated clean safety profile. Demonstration of efficacy in OCI-lLy10 mouse tumor model is ongoing. In summary, a series of potent IRAK-4 inhibitors belonging to 3 different chemical series have been discovered and are being evaluated for treatment of B-cell lymphomas. Citation Format: Wesley Roy Balasubramanian, Venkateshwar Rao Gummadi, Ravi Krishna Babu D, Sivapriya Marappan, Bhavesh Choudhary, Sreevalsam Gopinath, Kavitha Nellore, Shekar Chelur, Girish Daginakatte, Murali Ramachandra. Novel IRAK-4 inhibitors exhibit highly potent anti-proliferative activity in DLBCL cell lines with activating MYD88 L265P mutation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3646. doi:10.1158/1538-7445.AM2015-3646