Taisheng Huang

Discovery of INCB10820/PF-4178903, a potent, selective, and orally bioavailable dual CCR2 and CCR5 antagonist.

We report the discovery of a potent, selective, and orally bioavailable dual CCR2 and CCR5 antagonist (3S,4S)-N-[(1R,3S)-3-isopropyl-3-({4-[4-(trifluoromethyl)pyridin-2-yl]piperazin-1-yl}carbonyl)cyclopentyl]-3-methoxytetrahydro-2H-pyran-4-amine (19). After evaluation in 28-day toxicology studies, compound 19 (INCB10820/PF-4178903) was selected as a clinical candidate.

Discovery of INCB3344, a potent, selective and orally bioavailable antagonist of human and murine CCR2.

Rational design based on a pharmacophore of CCR2 antagonists reported in the literature identified lead compound 9a with potent inhibitory activity against human CCR2 (hCCR2) but moderate activity against murine CCR2 (mCCR2). Modification on 9a led to the discovery of a potent CCR2 antagonist 21 (INCB3344) with IC(50) values of 5.1 nM (hCCR2) and 9.5 nM (mCCR2) in binding antagonism and 3.8 nM (hCCR2) and 7.8 nM (mCCR2) in antagonism of chemotaxis activity. INCB3344 exhibited >100-fold selectivity over other homologous chemokine receptors, a free fraction of 24% in human serum and 15% in mouse serum, and an oral bioavailability of 47% in mice, suitable as a tool compound for target validation in rodent models.

Discovery of INCB8761/PF-4136309, a Potent, Selective, and Orally Bioavailable CCR2 Antagonist.

We report the discovery of a new (S)-3-aminopyrrolidine series of CCR2 antagonists. Structure-activity relationship studies on this new series led to the identification of 17 (INCB8761/PF-4136309) that exhibited potent CCR2 antagonistic activity, high selectivity, weak hERG activity, and an excellent in vitro and in vivo ADMET profile. INCB8761/PF-4136309 has entered human clinical trials.

Discovery of INCB3284, a Potent, Selective, and Orally Bioavailable hCCR2 Antagonist.

We report the identification of 13 (INCB3284) as a potent human CCR2 (hCCR2) antagonist. INCB3284 exhibited an IC50 of 3.7 nM in antagonism of monocyte chemoattractant protein-1 binding to hCCR2, an IC50 of 4.7 nM in antagonism of chemotaxis activity, an IC50 of 84 μM in inhibition of the hERG potassium current, a free fraction of 58% in protein binding, high selectivity over other chemokine receptors and G-protein-coupled receptors, and acceptable oral bioavailability in rodents and primates. In human clinical trials, INCB3284 exhibited a pharmacokinetic profile suitable for once-a-day dosing (T 1/2 = 15 h).

Discovery of INCB9471, a Potent, Selective, and Orally Bioavailable CCR5 Antagonist with Potent Anti-HIV-1 Activity.

To identify a CCR5 antagonist as an HIV-1 entry inhibitor, we designed a novel series of indane derivatives based on conformational considerations. Modification on the indane ring led to the discovery of compound 22a (INCB9471) that exhibited high affinity for CCR5, potent anti-HIV-1 activity, high receptor selectivity, excellent oral bioavailability, and a tolerated safety profile. INCB9471 has entered human clinical trials.

Abstract 1336: Novel immunotherapeutic activity of JAK and PI3Kδ inhibitors in a model of pancreatic cancer

Immunotherapeutic agents are emerging as key components of efficacious multi-agent regimens in cancer. The majority of immunotherapeutic agents developed thus far either attempt to stimulate a more productive anti-tumoral immune response or to inhibit key proteins in the immunosuppressive tumoral milieu. In contrast, agents targeting signal transduction molecules have been largely developed for their ability to impact the proliferative potential of tumor cells directly. Notably, the JAK/STAT and PI3Kδ signaling pathways have been shown to contribute not only to tumor cell proliferation and survival but also to play a crucial role in regulating stromal cells, including immune cells, which are recruited to the tumor microenvironment. Activation of these pathways has been shown to result in the recruitment and expansion of predominantly negative regulatory cells such as myeloid derived suppressor cells and regulatory T cells, suggesting that inhibition of JAK/STAT and PI3Kδ signaling may promote antitumor immunity. Therefore, we have examined the immunotherapeutic potential of selective inhibitors of either JAK or PI3Kδ. We demonstrate that inhibitors of either JAK or PI3Kδ block tumor growth as single agents in the immuno-competent syngeneic PAN02 pancreatic model, which is not driven by oncogenic JAK or PI3K signaling. Tumor growth inhibition is not observed in immunocompromised mice, demonstrating that the anti-tumor effects of these agents require an intact immune system. These agents were tested pairwise with each other and in combination with other immune checkpoint modulators, including an anti-PD-L1 antibody and the IDO1 inhibitor INCB24360. The combinations of JAK inhibition with IDO1 inhibition, PI3Kδ inhibition or PD-1/PD-L1 blockade resulted in enhanced efficacy. Mechanistic studies revealed that the combination of JAK and IDO1 inhibition did not alter the number of infiltrating T cells within the tumor, but instead resulted in a more activated phenotype of the infiltrating T cells, leading to higher levels of IFNγ production. In contrast, combination treatment with regimens that included an inhibitor to PI3Kδ led to a marked increase in the numbers of T cell infiltrates, although the cells were not maximally activated. Further studies to understand the complex cellular responses elicited by these inhibitors may provide the mechanistic rationale to explore JAK or PI3Kδ inhibitor-based immunotherapy combinations in the clinic. Citation Format: Holly K. Koblish, Michael Hansbury, Liang-Chuan S. Wang, Gengjie Yang, Taisheng Huang, Chu-Biao Xue, Yun-Long Li, Eddy Yue, Andrew Combs, Wenqing Yao, Reid Huber, Peggy Scherle. Novel immunotherapeutic activity of JAK and PI3Kδ inhibitors in a model of pancreatic cancer. [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 1336. doi:10.1158/1538-7445.AM2015-1336

Abstract 691: Activity of the BET inhibitor INCB054329 in models of multiple myeloma

Multiple myeloma (MM) is a disease of plasma cell transformation. Current therapy for MM is initially effective, but nearly all tumors relapse, making new therapeutic options a necessity. Due to their efficacy in MM models, small molecule inhibitors of Bromodomain and Extra Terminal (BET) proteins have generated much interest as potential therapeutic agents for MM. Efficacy from BET inhibitors in MM is thought to be driven by their ability to reduce transcript levels of the c-myc oncogene. Current MM standard of care (SoC) therapeutics include lenalidomide (Revlimid, Celgene), bortezomib (Velcade, Takeda), and Melphalan (Alkeran, GlaxoSmithKline). In preparation for potential clinical studies, these MM SoC agents were each combined with a potent pan-BET inhibitor, INCB054329, for in vitro and in vivo studies. In vitro, treatment of MM cell lines with INCB054329 inhibited expression of c-MYC, induced HEXIM1 levels and inhibited cell growth with potencies less than 200 nM. Combination of INCB054329 with SoC therapeutics showed synergistic effects in blocking MM cell proliferation. INA-6 and MM1.S mouse xenograft models of MM were utilized to study the effects of the combination of INCB054329 with the MM SoC agents in vivo. In each instance (INCB054329/lenalidomide, INCB054329/bortezomib, INCB054329/melphalan), additive to synergistic effects, as measured by inhibition of subcutaneous tumor growth, were seen in both models of MM. Since lenalidomide has recently been shown to bind the ubiquitin ligase cereblon (CRBN), leading to the degradation of two Ikaros family members, IKZF1 and IKZF3, that are essential to B cell fate and survival, we examined whether there could be functional overlap between BET inhibition and the downstream effects of lenalidomide. From MM1.S xenograft pharmacodynamic assays, we found a synergistic repression of c-MYC protein levels at 3hr post dose for the combination of INCB054329 and lenalidomide. Interestingly, the sharp decline in c-MYC protein levels in the MM1.S model appears to be independent of the IRF4 pathway, as IRF4 protein levels do not decrease until 24 hrs post dose of lenalidomide. Overall, our data indicate that INCB054329 may provide a novel combination partner with current standard of care therapies for MM, and support the clinical evaluation of the compound within the anti-myeloma treatment landscape. Citation Format: Matthew Stubbs, Xiaoming Wen, Valerie Dostalik, Sybil O9Connor, Eian Caulder, Alla Vogina, Thomas Maduskuie, Richard Sparks, Taisheng Huang, Nikoo Falahatpisheh, Padmaja Polam, Chu-Biao Xue, Xuesong M. Liu, Timothy Burn, Kris Vaddi, Andrew P. Combs, Reid Huber, Gregory Hollis, Peggy Scherle, Phillip CC Liu. Activity of the BET inhibitor INCB054329 in models of multiple myeloma. [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 691. doi:10.1158/1538-7445.AM2015-691

Abstract 779: Blockade of the IL-6/JAK/STAT3 signaling pathway inhibits pancreatic tumor cell growth in 3D spheroid cultures and in xenograft models

Emerging evidence has demonstrated the importance of tumor-associated inflammation in the development and progression of pancreatic ductal adenocarcinoma. Specifically, constitutive activation of the inflammation-related IL-6/JAK/STAT3 signaling pathway has been reported in pancreatic tumors and has been suggested to be a poor prognostic factor for overall survival in patients with advanced disease. The aim of this study was to assess the effects of inhibition of IL-6/JAK/STAT3 signaling on pancreatic cell growth in vitro and tumor growth in vivo. INCB039110, a JAK1 selective inhibitor currently in multiple Phase 2 clinical trials, was used to block the IL-6/JAK/STAT3 signaling pathway in cells. We show that while inhibition of IL-6/JAK/STAT3 signaling by INCB039110 showed no effects on the proliferation of pancreatic cell lines grown under conventional 2D monolayer cell culture conditions, this inhibitor demonstrated growth inhibitory activity against the pancreatic tumor cell lines, Hs700T and BxPC-3, in a 3D-spheroid culture system. Importantly, addition of cytokines that stimulated JAK/STAT3 signaling in these cells significantly promoted the growth of the spheroids, and this could be completely reversed by INCB039110. Furthermore, JAK1 inhibition enhanced the cytotoxicity induced by gemcitabine in both Hs700T and BxPC-3 spheroids in a combination study. The results were confirmed with another novel Jak1 selective inhibitor, INCB052793 which is currently in a Phase 1 clinical trial in patients with advanced malignancies. Since elevated serum IL-6 and its correlation with cachexia has been observed in pancreatic cancer, we tested and found that INCB039110 prevented weight loss in an IL-6 induced cachexia model in mice. Finally, we show that INCB039110 blocked tumor growth in human pancreatic xenograft models in mice at clinically relevant doses, both as monotherapy and in combination with cytotoxic agents such as gemcitabine. Thus, we demonstrate that pharmacological blockade of the IL-6/JAK/STAT3 signaling pathway with a JAK1 selective inhibitor can have both tumor intrinsic and extrinsic effects resulting in the inhibition of pancreatic tumor cell growth and the modulation of inflammation-associated cachexia. These data suggest that pancreatic cancer patients may potentially benefit from JAK1 inhibitors in the clinic. Citation Format: Jun Li, Eian Caulder, Margaret Favata, Melody Diamond, Beth Rumberger, Holly Koblish, Taisheng Huang, Chu-Biao Xue, Wenqing Yao, Jordan Fridman, Peggy Scherle, Mike Liu, Reid Huber, Kris Vaddi. Blockade of the IL-6/JAK/STAT3 signaling pathway inhibits pancreatic tumor cell growth in 3D spheroid cultures and in xenograft models. [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 779. doi:10.1158/1538-7445.AM2015-779