Loic Vincent

Discovery and optimization of new benzimidazole- and benzoxazole-pyrimidone selective PI3Kβ inhibitors for the treatment of phosphatase and TENsin homologue (PTEN)-deficient cancers.

Most of the phosphoinositide-3 kinase (PI3K) kinase inhibitors currently in clinical trials for cancer treatment exhibit pan PI3K isoform profiles. Single PI3K isoforms differentially control tumorigenesis, and PI3Kβ has emerged as the isoform involved in the tumorigenicity of PTEN-deficient tumors. Herein we describe the discovery and optimization of a new series of benzimidazole- and benzoxazole-pyrimidones as small molecular mass PI3Kβ-selective inhibitors. Starting with compound 5 obtained from a one-pot reaction via a novel intermediate 1, medicinal chemistry optimization led to the discovery of compound 8, which showed a significant activity and selectivity for PI3Kβ and adequate in vitro pharmacokinetic properties. The X-ray costructure of compound 8 in PI3Kδ showed key interactions and structural features supporting the observed PI3Kβ isoform selectivity. Compound 8 achieved sustained target modulation and tumor growth delay at well tolerated doses when administered orally to SCID mice implanted with PTEN-deficient human tumor xenografts.

Discovery and optimization of pyrimidone indoline amide PI3Kβ inhibitors for the treatment of phosphatase and tensin homologue (PTEN)-deficient cancers.

Compelling molecular biology publications have reported the implication of phosphoinositide kinase PI3Kβ in PTEN-deficient cell line growth and proliferation. These findings supported a scientific rationale for the development of PI3Kβ-specific inhibitors for the treatment of PTEN-deficient cancers. This paper describes the discovery of 2-[2-(2,3-dihydro-indol-1-yl)-2-oxo-ethyl]-6-morpholin-4-yl-3H-pyrimidin-4-one (7) and the optimization of this new series of active and selective pyrimidone indoline amide PI3Kβ inhibitors. 2-[2-(2-Methyl-2,3-dihydro-indol-1-yl)-2-oxo-ethyl]-6-morpholin-4-yl-3H-pyrimidin-4-one (28), identified following a carefully designed methyl scan, displayed improved physicochemical and in vitro pharmacokinetic properties. Structural biology efforts enabled the acquisition of the first X-ray cocrystal structure of p110β with the selective inhibitor compound 28 bound to the ATP site. The nonplanar binding mode described herein is consistent with observed structure-activity relationship for the series. Compound 28 demonstrated significant in vivo activity in a UACC-62 xenograft model in mice, warranting further preclinical investigation. Following successful development, compound 28 entered phase I/Ib clinical trial in patients with advanced cancer.

Preparation and optimization of new 4-(morpholin-4-yl)-(6-oxo-1,6-dihydropyrimidin-2-yl)amide derivatives as PI3Kβ inhibitors.

From a HTS campaign, a new series of pyrimidone anilides exemplified by compound 1 has been identified with good inhibitory activity for the PI3Kβ isoform. The structure of compound 1 in PI3Kγ was solved revealing a binding mode in agreement with the SAR observed on PI3Kβ. These compounds displayed inhibition in the nanomolar range in the biochemical assay and were also potent p-Akt inhibitors in a PTEN-deficient PC3 prostate cancer cell line. Optimization of in vitro pharmocokinetic properties led to compound 25 exhibiting 52% bioavailability in mice and target engagement in an acute PK/PD study.

Abstract B2: Switching to aflibercept treatment resulted in greater tumor responses than continuous bevacizumab treatment in patient-derived xenograft models of colorectal cancer.

Background: The recombinant fusion protein aflibercept (afl) binds VEGF-A, -B, and placental growth factor (PlGF). Based on an OS benefit observed in the phase 3 VELOUR trial, aflibercept in combination with FOLFIRI was approved for patients with metastatic colorectal cancer (mCRC) following a prior oxaliplatin-containing regimen. In vitro, afl inhibited VEGFR signaling more potently and blocked cell migration more effectively vs. bevacizumab (bev) which only binds VEGF-A. Recent in vivo studies comparing the anti-tumor activity of afl vs. bev were conducted in patient-derived xenograft (PDX) CRC models. The PDX models are clinically relevant as they represent common genetic backgrounds in CRC and were derived from primary tumors or from metastases. A sequential treatment regimen of aflibercept post-bev vs. continuation of bev treatment was investigated. Methods: Forty eight different CRC adenocarcinoma tumors were engrafted subcutaneously (SC) into NMRI nude mice to generate 48 distinct PDX CRC models. ELISA and Luminex measured the expression of mouse and human VEGF-A and mouse and human PlGF in untreated tumors. Tumor-bearing mice (8 mice/group) were dosed with afl, bev, or placebo 2x/wk for 3 wks and SC tumor measurements were recorded 2x or 3x/wk. In 3 PDX models, mice that were treated with bev were randomized and either switched to afl treatment or continued to receive bev. Activity was expressed as relative change in tumor volume between treatment (ΔT) and control (ΔC) at 3 wks. A ΔT/ΔC ≤0% indicated complete tumor stasis. Student9s t tests evaluated statistical differences in final tumor volumes. Results: Aflbercept induced complete tumor stasis in 31/48 PDX CRC models and bev in 2/48 PDX CRC models. The PDX models were characterized into 2 phenotypes based on statistical analysis: phenotype A, where afl activity was greater than bev activity (39 /48 PDX), and phenotype B, where there was no significant difference between the 2 drugs (9/48 PDX). Three models in which bev treatment resulted in eventual tumor escape vs. continuous inhibition by afl were selected for sequential treatment of bev followed by afl. Afl treatment began after bev treatment resulted in a greater than 2-fold increase in tumor volume. Greater anti-tumor activity occurred when afl was administered after bev vs. continuous bev treatment. At the end of the study, the tumor volumes were statistically significantly different between the afl and bev groups (T test p values Conclusions: Aflibercept induced complete tumor stasis more frequently in CRC PDX models than bevacizumab. As tumor levels of hVEGF-A were far greater than mVEGF-A, the inability of bevacizumab to bind mVEGF-A is unlikely to explain the higher and more consistent activity of aflibercept. In all 3 PDX models tested, switching to aflibercept treatment after bev treatment resulted in a greater tumor response than continuous bev treatment. The greater response to aflibercept than bev after an initial treatment with bev suggests that individual patients may derive more benefit from aflibercept than bev in second line treatment after an initial bev-based regimen. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B2. Citation Format: Marielle Chiron, Rebecca G. Bagley, Jack Pollard, Christophe Henry, Parminder Mankoo, Loic Vincent, Catherine Geslin, Tatjana Kloss, Donald A. Bergstrom. Switching to aflibercept treatment resulted in greater tumor responses than continuous bevacizumab treatment in patient-derived xenograft models of colorectal cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B2.

Preparation and optimization of new 4-(2-(indolin-1-yl)-2-oxoethyl)-2-morpholinothiazole-5-carboxylic acid and amide derivatives as potent and selective PI3Kβ inhibitors

In our continuous efforts to identify and develop novel targeted cancer treatments, a new morpholino-thiazole scaffold active against PI3Kβ has been identified. This Letter reports the optimization of this compound class to develop PI3Kβ isoform-selective inhibitors with suitable pharmacological properties.

Abstract 4638: Anti-tumor activity of pimasertib in combination with SAR245409 or SAR245408 in human primary colorectal cancer xenograft models bearing PI3K/KRas and KRas mutations.

The PI3K/AKT/mTOR and Ras/Raf/MEK/ERK are interlinked growth and survival signaling pathways that are often constitutively activated in human tumors as a result of amplifications and/or mutations in PIK3CA, RAS and BRAF genes. In the present work, we have investigated the anti-tumor activity and documented the steady state pharmacodynamic impact of combinations between 2 selective pan PI3K Class I inhibitors, SAR245408 (XL147) and SAR245409 (XL765) with the selective allosteric inhibitor of MEK1/2, pimasertib (AS703026; MSC1936369B) against several different patient derived colorectal cancer (CRC) xenograft models harboring either KRAS mutations, dual KRAS and BRAF mutations or dual KRAS and PIK3CA mutations. In the BRAF driven CRC model, effects of the combinations were not significantly different from that of single agent treatment of pimasertib alone. In the G12V KRAS or G12D KRAS mutant CRC models, both combinations led to significantly greater anti-tumor activity than that of single agent treatment. In the dual PIK3CA/KRAS mutant tumors, combination therapies lead to a potent inhibition of both TORC1 and TORC2 pathways, in addition to inhibition of the MAPK pathway in contrast to single agent treatments. Overall, pimasertib combined with either SAR245409 or SAR245408 showed a significantly greater anti-tumor activity as compared to single agent treatment alone in primary models bearing KRAS mutations or dual PIK3CA/KRAS mutations. The combination of pimasertib and SAR245409 is currently being investigated in patients with PIK3CA/KRAS mutant colorectal cancer as part of an ongoing Phase Ib dose escalation trial of oral combination therapy with pimasertib (MSC1936369B) and SAR245409 in subjects with locally advanced or metastatic solid tumors. Citation Format: Sukhvinder S. Sidhu, Coumaran Egile, Marc Malfilatre, Celine Lefranc, Yvette Ruffin, Jianguo Ma, Karl Hsu, Joanne Lager, Stephane Marzabal, Janet A. Ogden, Loic Vincent. Anti-tumor activity of pimasertib in combination with SAR245409 or SAR245408 in human primary colorectal cancer xenograft models bearing PI3K/KRas and KRas mutations. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4638. doi:10.1158/1538-7445.AM2013-4638

Abstract 3258: Discovery and characterization of SAR260301, a novel PI3Kβ-selective inhibitor in clinical development for the treatment of PTEN-deficient tumors .

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DCnnThe PI3K/mTOR pathway is involved in promoting tumor cell proliferation, survival and metastasis. The development of new anticancer therapies targeting different components of this pathway has been motivated by the identification of somatic PIK3CA missense mutations as well as the high frequency of loss of negative regulatory proteins such as the tumor suppressor PTEN. In this last case, the abnormal activation of downstream effectors is mediated by PI3Kβ. PTEN deficiency has also been reported to be involved in the resistance to a variety of anticancer therapies. The preceding findings support investigation into selective modulators of the lipid kinase activity of p110β as agents for the treatment of PTEN-deficient tumors, with potentially reduced on-target adverse events described for pan-PI3K inhibitors currently undergoing clinical trials.nnSAR260301 is a selective PI3Kβ lipid kinase inhibitor that has demonstrated higher potency in vitro on p110β (IC50= 52 nM) than on p110δ and p110α isoforms and no or weak activity against p110γ, mTOR and a wide range of protein kinases (>400 enzymes). The potency and selectivity against the intended target was further confirmed in mechanistic cellular models (IC50 = 32 nM, p110β; 26- and 88-fold selective over p110δ and p110α, respectively). Moreover, SAR260301 also modulates pAkt levels exclusively in PTEN-deficient tumor cell lines with IC50 values ranging from 39 to 310 nM and from 20 to 209 nM for pAkt-S473 and pAkt-T308, respectively. When administered orally, the compound shows dose and time-dependent inhibition of the PI3K pathway in human PTEN-deficient tumor xenografts in mice. In these models, target engagement correlates with compound exposure and is associated with good tolerability.nnThe MAPK pathway also plays an important role in cancer and is often constitutively and simultaneously activated with the PI3K pathway. Furthermore, PTEN loss has been shown to correlate with resistance to MAPK inhibitors. Preclinical data evidencing the ability of SAR260301 to modulate pAkt levels in genetic contexts where PTEN deficiency co-exists with MAPK pathway activation, as well as the effects of combining SAR260301 with MAPK inhibitors will also be presented.nnThe foregoing studies support ongoing Phase I clinical investigation of SAR260301 in patients with PTEN-deficient malignancies.nnCitation Format: Angela Virone-Oddos, Helene Bonnevaux, Olivier Lemaitre, Loic Vincent, Franck Halley, Brigitte Demers, Veronique Charrier, Olivier Courtin, Stephane Guerif, Laurent Besret, Pierre-Yves Abecassis, Sylvaine Cartot-Cotton, Gary Emmons, Alan Roberts, David Compton, Bin Wu, Laurent Schio, Christoph Lengauer, Carlos Garcia-Echeverria. Discovery and characterization of SAR260301, a novel PI3Kβ-selective inhibitor in clinical development for the treatment of PTEN-deficient tumors . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3258. doi:10.1158/1538-7445.AM2013-3258

Abstract A48: Anti-tumor activity of the MEK inhibitor pimasertib in combination with the PI3K/mTOR inhibitor SAR245409 in low-grade serous ovarian cancer

Low-grade serous ovarian carcinoma is a distinct neoplasm from high-grade serous ovarian carcinoma and is chemo-resistant, both in the first line setting as well as in subsequent lines of therapy. Serous ovarian tumors of low malignant potential and low grade serous ovarian cancer (LGSOC) appear to be dependent, in part, on the activation of the mitogen-activated protein kinase (MAPK) survival signaling pathway, and furthermore display significantly higher prevalence of KRAS or BRAF mutations in contrast to high-grade serous carcinomas.nnThe PI3K/AKT/mTOR and Ras/Raf/MEK/ERK (MAPK) survival pathways are interlinked survival signaling pathways, where compensatory activation of one of the pathways in response to the inhibition of the other has been observed. Given their ability to cross-talk, simultaneous inhibition of the MAPK and PI3K/PTEN signaling cascades may significantly enhance anti-tumor activity as compared with inhibition of either cascade alone. Preclinical studies have shown that the combination of MEK and PI3K inhibitors, both in vitro and in vivo, enhanced anti-tumor effects and induced apoptosis in cell lines and primary patient-derived models across a range of cancer types. In the present series of studies, we report: 1- the anti-tumor activity of the combination of two investigational drugs, a phosphatidylinositol 3-kinase (PI3K) and mTOR inhibitor, SAR245409 (XL765) with the selective allosteric inhibitor of MEK1/2, pimasertib (AS703026; MSC1936369B) against patient-derived ovarian cancer xenograft models harboring KRAS mutations from low, intermediate and high grade ovarian tumors), and 2- the preliminary clinical activity of the combination in ovarian patients.nnIn patient-derived xenografts of low and intermediate grade ovarian cancer, the combination led to significantly greater antitumor activity than that of single agent treatments. In the high grade model of ovarian cancer, no additive effects on antitumor activity were observed in the combination as compared to pimasertib as a single agent.nnThe combination of pimasertib and SAR245409 is currently being investigated in patients with refractory solid tumors in an ongoing Phase Ib Trial (EMR200066-006; [NCT01390818][1]), where objective responses have been reported in 2 out of 4 evaluable patients with low-grade serous ovarian carcinoma. A phase 2 study (EMR200066-012, EudraCT Number 2013-000902-40) will investigate the activity of the combination pimasertib and SAR245409 in subjects with recurrent or metastatic low grade ovarian cancer, a patient population which has a high unmet medical need.nnCitation Format: Sukhvinder S. Sidhu, Frank Campana, Coumaran Egile, Karl Hsu, Samantha Goodstal, Ekaterine Asatiani, Lars Damstrup, Joanne Lager, Janet Ogden, Loic Vincent. Anti-tumor activity of the MEK inhibitor pimasertib in combination with the PI3K/mTOR inhibitor SAR245409 in low-grade serous ovarian cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr A48.nn [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01390818&atom=%2Fclincanres%2F19%2F19_Supplement%2FA48.atom

Abstract 2775: Antitumor activity of cabazitaxel in pediatric tumor xenografts

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, ILnnBackground: Cabazitaxel (Jevtana®), a novel semi-synthetic taxane derived from 10-deacetyl baccatin III, was recently approved by the FDA and EMA for patients with metastatic hormone-refractory prostate cancer previously treated with docetaxel-based therapy. Cabazitaxel, which stabilizes in vitro microtubules as efficiently as docetaxel, was selected for clinical development for several reasons including: better anti-proliferative activity than docetaxel against chemotherapy resistant tumor cell lines (Bissery MC, AACR 2000), broad spectrum of in vivo anti-tumor activity docetaxel-sensitive tumors, and activity in tumor models in which docetaxel was either poorly active or inactive (Vrignaud P, AACR 2000). Interestingly, unlike docetaxel, cabazitaxel is able to cross the blood-brian barrier (Dykes DJ, AACR 2000) and has demonstrated activity in intracranial human glioblastomas. Further, in preclinical studies the combination of cabazitaxel and cisplatin exhibit therapeutic synergism (Vrignaud P, AACR 2011). Methods: In order to explore other therapeutic indications, the anti-tumor activity of cabazitaxel was evaluated in comparison to docetaxel in 3 different xenograft models of human pediatric tumors: RH-30 (rhabdomyosarcoma), TC-71 and SK-ES-1 (Ewings tumors) in SCID female mice. Cabazitaxel and docetaxel were administered as single agents, IV in a dose response study (14.5, 9.0, 5.6 & 3.5 mg/kg), 5 days apart (e.g., days 14 and 18) after SC tumor implantation. Results: In the rhabdomysarcoma RH-30 model, cabazitaxel achieved 100% complete regression (CR) at the 2 highest dose levels and tumor regressions were also observed at the third dose level. Tumor free survivors (TFS on day 120) were observed only in the cabazitaxel treatment groups, 14.5 mg/kg (6/6) and at 9 mg/kg (5/6). In comparison, docetaxel induced CR only at the highest dose-level (14.5 mg/kg) tested. Against TC-71, cabazitaxel achieved 6/7 TFS at14.5 mg/kg and 9 mg/kg and 6/7 partial regressions (PR) were observed at 5.6 mg/kg. However, docetaxel only induced CR at the highest dose-level tested (14.5 mg/kg) with 1/7 TFS at day 120. Against SK-ES-1, cabazitaxel achieved 100% PR at 14.5, 9.0, 5.6 mg/kg, with 6/7 CR, leading to 3/7 TFS at the highest doses tested. In comparison, docetaxel induced 3/7 CR at the highest dose tested and no TFS were observed. Conclusion: Both cabazitaxel and docetaxel showed significant antitumor activity in all 3 human pediatric tumor xenografts; however, cabazitaxel demonstrated greater activity than docetaxel at comparable dose levels. Taken together, preclinical data with cabazitaxel including activity in brain tumors and therapeutic synergism with cisplatin, support its development in pediatric indications.nnCitation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2775. doi:1538-7445.AM2012-2775

Abstract LB-208: Hijacking the PI3K/mTor and KRas/MEK/ERK signaling pathways with a therapeutic assault results in robust antitumor activity in PI3K/KRas and KRas mutant tumors

The PI3K/AKT/mTOR and Ras/Raf/MEK/ERK are interlinked growth and survival signaling pathways both involving regulation by Ras and often constitutively activated in human tumors as a result of frequent mutations in p1 10α, Ras and BRaf. Here, we have assessed the antitumor activity of the oral, potent and selective allosteric inhibitor of MEK1/2, MSC1936369 (formerly known as AS703026), in combination with SAR245408 (pan-PI3K formerly named XL147) or SAR245409 (dual panPI3K/mTOR formerly named XL765) in cellular in vitro and in vivo xenograft settings. In vitro, the anti-proliferative effects of MSC1936369 in combination with SAR245409 were evaluated in a panel of 81 tumor cell lines (17 indications). Potent combination effects were seen in colorectal, pancreatic, breast and NSCL cancers when compared to each agent alone. Across indications, tumor cells harboring mutations in KRas, p1 10α, BRaf and both p1 10α and KRas were identified as those more sensitive to the combination. In vivo, suboptimal therapeutic doses of MSC1936369, SAR245408 and SAR245409 were tested PO daily as single agents and in combination in human tumor xenograft models: MiaPaCa-2 pancreatic carcinoma (KRas mut), HCT116 colorectal adenocarcinoma (KRas/PIKC3A mut). In animals bearing MiaPaCa-2 xenografts, tumor growth inhibition was observed in all of the treatment groups, to varying degrees, compared to vehicle (p Overall, the combination treatment of the MEK inhibitor MSC1936369 and the dual panPI3K/mTOR inhibitor SAR245409 showed enhanced tumor inhibition both in a large battery of tumor-derived cell lines as well as in xenograft models of human cancer (KRas mut and dual PI3K/KRas mut). In addition, combination therapy with the panPI3K inhibitor SAR245408 demonstrated a robust gain of antitumor activity, particularly in the dual PI3K/KRas mutant tumors. The available preclinical pharmacological data support the use of these combinations in clinical settings. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-208. doi:10.1158/1538-7445.AM2011-LB-208