Sivapriya Marappan

Debio 0617B Inhibits Growth of STAT3-Driven Solid Tumors through Combined Inhibition of JAK, SRC, and Class III/V Receptor Tyrosine Kinases.

Tumor survival, metastases, chemoresistance, and escape from immune responses have been associated with inappropriate activation of STAT3 and/or STAT5 in various cancers, including solid tumors. Debio 0617B has been developed as a first-in-class kinase inhibitor with a unique profile targeting phospho-STAT3 (pSTAT3) and/or pSTAT5 in tumors through combined inhibition of JAK, SRC, ABL, and class III/V receptor tyrosine kinases (RTK). Debio 0617B showed dose-dependent inhibition of pSTAT3 in STAT3-activated carcinoma cell lines; Debio 0617B also showed potent antiproliferative activity in a panel of cancer cell lines and in patient-derived tumor xenografts tested in an in vitro clonogenic assay. Debio 0617B showed in vivo efficacy by inhibiting tumor growth in several mouse xenograft models. To increase in vivo efficacy and STAT3 inhibition, Debio 0617B was tested in combination with the EGFR inhibitor erlotinib in a non–small cell lung cancer xenograft model. To evaluate the impact of in vivo STAT3 blockade on metastases, Debio 0617B was tested in an orthotopic tumor model. Measurement of primary tumor weight and metastatic counts in lung tissue demonstrated therapeutic efficacy of Debio 0617B in this model. These data show potent activity of Debio 0617B on a broad spectrum of STAT3-driven solid tumors and synergistic activity in combination with EGFR inhibition. Mol Cancer Ther; 15(10); 2334–43. ©2016 AACR.

Abstract 4649: ODM-207, a novel BET-bromodomain inhibitor as a therapeutic approach for the treatment of prostate and breast cancer

Introduction: BET (bromodomain and extraterminal) family proteins (BRD2, BRD3, BRD4, and BRDT) are epigenetic readers that bind to acetylated-lysine residues in histones and recruit protein complexes to promote transcription elongation. In many cancers, BET proteins have been shown to regulate expression of MYC and other oncogenic drivers that are important for cell proliferation and survival. Pharmacologic inhibition of the BET-histone interaction has been shown to result in transcriptional downregulation of a number of oncogenes and inhibition of tumor growth providing a novel strategy for treatment of cancer. Therefore, in this study, we evaluated the in vitro and in vivo antitumor activity of ODM-207, a novel, potent and highly selective BET bromodomain inhibitor using cell lines derived from prostate and breast cancer as well as patient-derived tumor cell cultures of breast cancer. Methods and Results: ODM-207 has antiproliferative effects on several hematological and solid tumor cell lines. In a panel of prostate cancer cell lines, ODM-207 attenuates cell growth of androgen receptor (AR)-positive cell lines such as VCaP and 22Rv1. RNA-sequencing and Western blot studies revealed that the exposure of sensitive prostate cancer cells to ODM-207 is associated with rapid down-regulation c-Myc expression levels while wtAR was not affected. In 22Rv1 prostate cancer xenograft, which expresses both the full-length androgen receptor and androgen receptor splice variant V7, oral administration of ODM-207 was very efficacious in suppressing tumor growth at well tolerated doses whereas enzalutamide had only a modest effect. Contrary to our findings in prostate cancer cells, BET-inhibitor treatment of estrogen-dependent MCF-7 breast cancer cell line inhibits tumor growth in cell proliferation assays but is associated with down-regulation of ERα while the c-Myc levels are very low, highlighting the context-dependent functional effects of BET inhibition. Interestingly, ODM-207 produces potent antiproliferative effects associated with cell-cycle arrest and cellular senescence in patient-derived breast cancer cells. Conclusions: In summary, ODM-207 is a new generation BET inhibitor found to possess excellent pharmacological properties and antitumor activity both in vitro and in vivo. Our data suggest the potential utilization of ODM-207 for the treatment of prostate and breast cancer. Citation Format: Mari Bjorkman, Elina Mattila, Reetta Riikonen, Chandra Sekhar, Mahaboobi Jaleel, Sivapriya Marappan, Tarja Ikonen, Daniel Nicorici Nicorici, Juha Rantala, Susanta Samajdar, Murali Ramachandra, Pekka Kallio, Anu-Maarit Moilanen. ODM-207, a novel BET-bromodomain inhibitor as a therapeutic approach for the treatment of prostate and breast cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4649.

Abstract 3070: Potent and selective inhibition of CDK7 by novel covalent inhibitors

Background: Phosphorylation of the RNA polymerase II (RNAPII) in C-terminal domain (CTD) by Cyclin-dependent kinase 7 (CDK7) is an important step in cellular transcription process. Hence pharmacological modulation of CDK7 kinase activity is considered as an interesting approach to treat cancers that critically dependent on transcription to maintain their oncogenic state. Experimental procedures: Multiple series of novel covalent CDK7 inhibitors were identified by SBDD approach based on the binding mode of known CDK7 inhibitors to find early hits. Iterative medicinal chemistry efforts were performed to identify several lead compounds by optimizing the initial hits to achieve good physicochemical properties, high potency, good selectivity and desirable pharmacokinetic profile. Summary: Highly potent ATP competitive covalent inhibitors of CDK7 from two distinct chemical series were identified. They show time-dependent inhibition of CDK7 enzyme activity as a proof of covalent binding and exhibit potent anti-proliferative activity in cell lines derived from various tumor types. CDK7 modulation by these compounds was also confirmed by monitoring cellular pS5RNAPII levels. Representative compounds from each series showed very good selectivity profile in broad kinase (332) panel. Lead molecules were identified based on excellent drug-like properties (solubility, permeability and good oral bioavailability). Tolerability and efficacy studies in rodent xenograft models are ongoing with selected leads to test their impact on tumor growth inhibition and to determine therapeutic window by oral administration. Conclusion: We have identified novel and selective CDK7 covalent inhibitors from two distinct chemical series with optimized drug-like properties including oral bioavailability. These compounds are being evaluated for anti-tumor activity in mouse xenograft models. Citation Format: Leena Khare Satyam, Ramulu Poddutoori, Subhendu Mukherjee, Sivapriya Marappan, Sreevalsam Gopinath, Raghuveer Ramachandra, Manoj Kumar Pothuganti, Shilpa S. Nayak, Nandish C, Chandranath Naik, Ravindra MV, Madhu B. Dabbeeru, Nagaraju A, Mahankali B, Thomas Antony, Chetan Pandit, Shekar Chelur, Girish Daginakatte, Susanta Samajdar, Murali Ramachandra. Potent and selective inhibition of CDK7 by novel covalent inhibitors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3070.

Abstract C190: Potent and selective inhibition of CDK7 by novel covalent inhibitors

Cyclin-dependent kinase 7 (CDK7) is an important constituent of the cellular transcriptional machinery, where it phosphorylates the C-terminal domain (CTD) of RNAP polymerase II (RNAPII). Because many tumor types are critically dependent on transcription for maintenance of their oncogenic state, pharmacological modulation of CDK7 kinase activity is considered as an approach to treat cancer. Multiple series of CDK7 inhibitors were identified by iterative medicinal chemistry efforts and SAR based approach. Early compounds were optimized towards attaining good physicochemical properties, high potency, good selectivity and desirable pharmacokinetic profile to achieve anti-tumor activity. We have identified compounds from two distinct chemical series that are highly potent in inhibiting CDK7 in biochemical assays. These inhibitors demonstrate time-dependent inhibition of CDK7 indicating covalent nature of binding. The compounds showed potent anti-proliferative activity in cell lines derived from various tumor types and this was accompanied by CDK7 modulation in cells as monitored by pS5RNAPII levels. They have excellent drug-like characteristics including solubility, permeability, metabolic stability and good oral bioavailability. In a broad panel of kinases (332 kinase), selected compounds from both series showed good selectivity profile. Tolerability and efficacy studies are ongoing with selected early leads to test their impact on tumor growth inhibition in xenograft models. We have identified novel and selective CDK7 covalent inhibitors from two series with desirable drug-like properties, which are being evauated for anti-tumor activity in xenograft models. Citation Format: Ramulu Poddutoori, Leena K. Satyam, Girish Daginakatte, Subhendu Mukherjee, Sivapriya Marappan, Sreevalsam Gopinath, Raghuveer Ramachandra, Anirudha Lakshminarasimhan, Manoj Pothuganti, Shilpa Nayak, Nandish C, Chandranath Naik, Ravindra MV, Madhu Dabbeeru, Thomas Antony, Chetan Pandit, Murali Ramachandra, Shekar Chelur, Susanta Samajdar. Potent and selective inhibition of CDK7 by novel covalent inhibitors. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C190.

Abstract LB-317: Identification of a novel preclinical candidate for CDK7 inhibition

Cyclin-dependent kinase 7 (CDK7) is an important constituent of the cellular transcriptional machinery, where it phosphorylates the C-terminal domain (CTD) of RNAP polymerase II (RNAPII). Because many tumor types are critically dependent on transcription for maintenance of their oncogenic state, pharmacological modulation of CDK7 kinase activity is considered as an approach to treat cancer. Multiple series of covalent CDK7 inhibitors were identified by iterative medicinal chemistry efforts and SAR based approach. These compounds were optimized towards attaining good physicochemical properties, high potency, good selectivity and desirable pharmacokinetic profile to achieve anti-tumor activity. We have now identified a pre-clinical candidate AU-BGB-002 which is highly potent in inhibiting CDK7 in biochemical as well as cellular assays while fully efficiently engaging the target. In a panel of kinases, AU-BGB-002 shows selectivity for CDK7. A panel of cell lines derived from a diverse set of indications are sensitive to AU-BGB-002. AU-BGB-002 exhibits excellent drug-like characteristics including solubility, permeability, metabolic stability and good oral bioavailability. When tested in a xenograft model, AU-BGB-002 treatment resulted in dose dependent tumor growth inhibition in AML xenograft model with tumor stasis at a dose of 10 mg/kg. Potent inhibiton of tumor growth was accompanied by complete target engagement and suppression of pS5RNAPII RNAPolII Ser5 phosphorylation in a parallel PK-PD study. Efficacy studies in additional xenograft models, advanced DMPK and toxicity studies are ongoing for this compound. In summary, we have identified a novel and selective CDK7 covalent inhibitor candidate with desirable drug-like properties that shows excellent efficacy in an AML xenograft model. Findings presented here support further development of AU-BGB-002 for the treatment of cancer. Citation Format: Leena K. Satyam, Ramulu Poddutoori, Subhendu Mukherjee, Sivapriya Marappan, Sreevalsam Gopinath, Aravind Basavaraju, Lakshmi Narayana Kaza, Manoj Kumar Pothuganti, Shilpa Nayak, Nandish C, Amith A, Ravindra MV, Dabbeeru Madhu Babu, Nagaraju A, Suraj Tgore, Thomas Antony, Chetan Pandit, Murali Ramachandra, Shekar Chelur, Girish Daginakatte, Susanta Samajdar. Identification of a novel preclinical candidate for CDK7 inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-317. doi:10.1158/1538-7445.AM2017-LB-317

Abstract 4798: Efficacy and safety of highly selective novel IRAK4 inhibitors for treatment of ABC-DLBCL

Interleukin-1 receptor associated kinases (IRAKs) are serine/threonine protein kinases belonging to the tyrosine-like kinase (TLK) family. IRAKs function as mediators of Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathways and play an important role in innate immune signaling. TLR/IL-1R stimulation leads to recruitment of MYD88, an adaptor molecule, to the activated receptor complex, which then complexes with IRAK4 and activates IRAK1. TRAF6 is then activated by IRAK1 leading to NFkB activation. Recent studies have reported the occurrence of gain of function oncogenic mutation (L265P) in MYD88 in ∼30% of activated B cell diffuse large B-cell lymphoma(ABC DLBCL) and ∼90% of Waldenstrom9s macroglobulinemia (WM) leading to constitutive activation of IRAK4 and NFkB pathway. Among the DLBCL subtypes (GCB, ABC DLBCL and PMBL), ABC DLBCL is the most refractory. Inhibition of constitutive IRAK4 signalling can be used as a therapeutic strategy to treat ABC DLBCL Small molecule inhibitors of IRAK4 were synthesized based on hits originating from Aurigene9s compound library. Structure guided drug design approach was used to further improve the potency. Lead compounds demonstrated moderate to very high selectivity towardsIRAK4 (S35 score of 0.03) when screened against a large panel of 329 kinases. Aurigene9s lead compounds have excellent PK profile and good oral bioavailability in mice, leading to good in-vivo activity in TLR4 induced cytokine release model. Selected lead compounds were tested in a OCI-Ly3 xenograft model, which has a MYD88(L265P) mutation leading to constitutive activation of IRAK4 signaling. An advanced lead compound has demonstrated excellent efficacy in OCI-Ly3 model, with tumor stasis at low doses and tumor regression at higher doses. The compound is well tolerated and has a good therapeutic window as determined in a 14 day rodent toxicity study. In summary, a selective IRAK4 inhibitor has been identified with excellent efficacy and good safety profile. Citation Format: Wesley Roy Balasubramanian, Venkateshwar Rao Gummadi, Kavitha Nellore, Subhendu Mukherjee, Sivapriya Marappan, Aravind Basavaraju, Bharathi Raja Ainan, Girish Daginakatte, Sreevalsam Gopinath, Sanjeev Giri, Thomas Antony, Shekar Chelur, Susanta Samajdar, Chetan Pandit, Murali Ramachandra. Efficacy and safety of highly selective novel IRAK4 inhibitors for treatment of ABC-DLBCL. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4798.

Abstract C191: Efficacy of novel IRAK4 inhibitors in ABC-DLBCL and AML models

Interleukin-1 receptor associated kinases (IRAKs) are serine/threonine protein kinases belonging to tyrosine-like kinase (TLK) family. The IRAK family consists of IRAK1, IRAK2, IRAK3 and IRAK4 out of which only IRAK1 and IRAK4 exhibit kinase activity. IRAKs function as mediators of Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling pathways and play an important role in innate immune signaling. Recent studies have reported the occurrence of oncogenic mutations in MYD88 in 30% of activated B cell diffuse large B-cell lymphoma (ABC DLBCL) and 90% of Waldenstrom9s macroglobulinemia (WM) leading to constitutive activation of the IRAK4 and NFkB pathway. Recent studies have also highlighted the association of dysregulated innate immune signaling with Myelodysplastic syndrome (MDS) and Acute Myeloid leukaemia (AML). TLRs and their associated signal transducers are frequently overexpressed and/or constitutively activated in MDS. Overexpression and activation of IRAK1 is observed in AML. Thus IRAKs are attractive therapeutic targets for treatment of tumors with altered innate immune signaling such as ABC DLBCL and AML. We have designed, synthesized and tested small molecule inhibitors of IRAK4 based on hits originating from Aurigene9s compound library. We have identified a series of novel bicyclic heterocycles as potent inhibitors of IRAK-4 with moderate to very high selectivity (S35 score = 0.03) in a 329 kinase panel. Lead compounds were profiled in proliferation and mechanistic assays (p-IRAK1 and p-TAK1 inhibition) in appropriate ABC DLBCL/AML cell lines. Aurigene lead compounds demonstrate potent inhibition of cellular proliferation with a good correlation to inhibition of phosphorylation of signaling intermediates in mechanistic assays. Lead compounds exhibit excellent PK profile and good oral bioavailability in mice. Preliminary in-vitro toxicology studies indicate a clean safety profile. Selected compounds demonstrate excellent in-vivo efficacy in relevant tumor models with >90% tumor growth inhibition and good in-vivo PD modulation. In summary, a series of potent and selective IRAK4 inhibitors have been discovered and are being evaluated for treatment of cancers with dysregulated innate immune signaling. Citation Format: Venkateshwar Rao, Wesley Roy Balasubramanian, Kavitha Nellore, Sivapriya Marappan, Aravind Basavaraju, Bharathi Raja Ainan, Girish Daginakatte, Sreevalsam Gopinath, Sanjeev Giri, Thomas Antony, Shekar Chelur, Susanta Samajdar, Chetan Pandit, Murali Ramachandra. Efficacy of novel IRAK4 inhibitors in ABC-DLBCL and AML models. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C191.

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

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 Waldenstrom9s 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