Arginase 1/2 inhibitor OATD-02: from discovery to first-in-man setup in cancer immunotherapy

Pharmacological inhibition of the controlling immunity pathway enzymes arginases 1 and 2 (ARG1 and ARG2) is a promising strategy for cancer immunotherapy. Here, we report the discovery and development of OATD-02, an orally bioavailable, potent arginases inhibitor. The unique pharmacological properties of OATD-02 are evidenced by targeting intracellular ARG1 and ARG2, as well as long drug-target residence time, moderate to high volume of distribution, and low clearance which may jointly provide a weapon against arginase-related tumor immunosuppression and ARG2-dependent tumor cell growth. OATD-02 monotherapy had an antitumor effect in multiple tumor models and enhanced an efficacy of the other immunomodulators. Completed non-clinical studies and human pharmacokinetic predictions indicate a feasible therapeutic window and allow for proposing a dose range for the first-in-human clinical study in cancer patients.

Open-label, single-center, phase I trial to investigate the mass balance and absolute bioavailability of the highly selective oral MET inhibitor tepotinib in healthy volunteers

Tepotinib (MSC2156119J) is an oral, potent, highly selective MET inhibitor. This open-label, phase I study in healthy volunteers (EudraCT 2013-003226-86) investigated its mass balance (part A) and absolute bioavailability (part B). In part A, six participants received tepotinib orally (498 mg spiked with 2.67 MBq [¹⁴C]-tepotinib). Blood, plasma, urine, and feces were collected up to day 25 or until excretion of radioactivity was <1% of the administered dose. In part B, six participants received 500 mg tepotinib orally as a film-coated tablet, followed by an intravenous [¹⁴C]-tepotinib tracer dose (53–54 kBq) 4 h later. Blood samples were collected until day 14. In part A, a median of 92.5% (range, 87.1–96.9%) of the [¹⁴C]-tepotinib dose was recovered in excreta. Radioactivity was mainly excreted via feces (median, 78.7%; range, 69.4–82.5%). Urinary excretion was a minor route of elimination (median, 14.4% [8.8–17.7%]). Parent compound was the main constituent in excreta (45% [feces] and 7% [urine] of the radioactive dose). M506 was the only major metabolite. In part B, absolute bioavailability was 72% (range, 62–81%) after oral administration of 500 mg tablets (the dose and formulation used in phase II trials). In conclusion, tepotinib and its metabolites are mainly excreted via feces; parent drug is the major eliminated constituent. Oral bioavailability of tepotinib is high, supporting the use of the current tablet formulation in clinical trials. Tepotinib was well tolerated in this study with healthy volunteers.

Abstract 4510: Model-based phase II dose selection of c-Met inhibitor MSC2156119J

Objectives: To evaluate the dose/exposure/target inhibition/tumor growth relationship of MSC2156119J, an orally administered, reversible, ATP-competitive, highly potent and selective c-Met receptor tyrosine kinase inhibitor, in order to determine the recommended phase II dose (RP2D) for the program.

Methods: Interim pharmacokinetic (PK) and biomarker (PD) data, i.e. plasma concentrations and c-Met inhibition in tumor biopsies from an ongoing first-in-human (FIM) solid tumor trial of MSC2156119J, were analyzed using the population modeling approach. The exposure/target inhibition relationship established in rich sampled KP-4 xenografted mice was utilized as prior information to develop the human model. Model-based simulations of the c-Met inhibition profiles in humans, aiming for a level that achieved tumor regression in mice, helped to determine the biologically active dose of MSC2156119J.

Results: During the FIM study, the maximum tolerated dose of MSC2156119J was not reached at a dose of 1,400 mg/day. Instead, a biologically active dose was selected as the RP2D, based on a translational modeling approach that integrated the quantitative relationship between dose, exposure, and target as well as tumor inhibition in humans and in a preclinical model. In KP-4 xenografted mice, tumor c-Met inhibition (quantified as normalized phosphorylated c-Met expression [pMET]) was described by a turnover full inhibitory Imax model, and tumor growth inhibition was best described by the Simeoni model. Simulations demonstrated that nearly complete pMET inhibition (≥95%) is required for tumor stasis or even regression. In the FIM study, a one-compartment linear model with an absorption transit compartment best described the PK of MSC2156119J at doses of 30-700 mg. The turnover model developed from mice data was applied to evaluate the level of c-Met inhibition in paired human tumor biopsies (taken pre- and on-treatment). System turnover parameters for pMET were set equal to those estimated in mice, while the treatment potency (1/IC50 of the inhibition of build-up) of MSC2156119J in humans was found to be 1.7-fold higher than that in mice. Assuming a 30% inter-individual variability in IC50, human simulations suggested that a 500-mg once-daily dose regimen of MSC2156119J could achieve continuous pMET inhibition of ≥95% in 90% of the population. The model and simulation will be confirmed using additional PK data and further tumor biopsies.

Conclusions: c-Met inhibition in human tumor lesions was described by a turnover model developed in KP-4 xenografted mice. Using this translational modeling and simulation approach and human PK and target inhibition data from paired tumor biopsies, a biologically active dose of 500 mg was proposed as the RP2D for MSC2156119J. This dose achieves continuous pMET inhibition of ≥95% in 90% of the population and has been adopted for the current development program for MSC2156119J.

Citation Format: Wenyuan Xiong, Samer El Bawab, Friedhelm Bladt, Michael Meyring, Manfred Klevesath, Gerald Falchook, David Hong, Andreas Johne, Pascal Girard. Model-based phase II dose selection of c-Met inhibitor MSC2156119J. [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 4510. doi:10.1158/1538-7445.AM2015-4510

Abstract 925: The c-Met inhibitor MSC2156119J effectively inhibits growth of liver cancer models

The mesenchymal-epithelial transition factor (c-Met) receptor, also known as hepatocyte growth factor receptor (HGFR), controls morphogenesis, a process physiologically required for embryonic development and tissue repair. Aberrant c-Met activation is associated with human malignancies, including hepatocellular carcinomas (HCC). The aim of this study was to evaluate the effect of a novel, highly selective c-Met inhibitor, MSC2156119J (EMD 1214063), in hepatocellular cancer models.

MHCC97H is a human HCC cell line co-expressing c-Met and HGF, and exhibiting high metastatic potential. The effect of MSC2156119J on MHCC97H was evaluated in a Balb/c nu/nu murine xenograft model in a subcutaneous and orthotopic setting. Tumor-bearing mice were orally treated with 100 mg/kg MSC2156119J (5 days on/2 days off). In the subcutaneous setting, MSC2156119J resulted in tumor regression in 10/10 mice, achieving tumor eradication in 9/10 mice. In the orthotopic model, MHCC97H tumor fragments proliferate in the liver and invariably metastasize to the lung (100%). MSC2156119J treatment started 7 days after tumor fragment implantation. After 5 weeks of treatment, mice were necropsied and a series of parameters were assessed. Primary tumor size and weight, and circulating Alpha-Feto-Protein levels were significantly lower in mice treated with MSC2156119J compared to controls (p&lt;0.001). Notably, treatment with MSC2156119J resulted in a reduced number of mice with visible lung metastasis (6/9), and correlated with a significantly lower number of metastatic foci in the lungs compared to control mice (p&lt;0.01).

To better predict the clinical efficacy of MSC2156119J, 9 patient-derived primary HCC explants models were used. The explants were subdivided into 3 groups, based on their c-Met levels and HGF expression. Each group comprised 3 tumors expressing high, intermediate, and low levels of c-Met and HGF, respectively. Mice were treated with MSC2156119J, sorafenib, or a combination of both.

MSC2156119J (100 mg/kg/5 out of 7 days) strongly inhibited tumor growth in 4/9 models (TGD range of 370% to 41%). Analysis of intratumoral c-Met, phospho c-Met and HGF levels indicated that explants with high levels of c-Met and HGF were more sensitive to MSC2156119J than low-expressing models. In 3/4 responsive models, MSC2156119J exhibited a better anti-tumor activity than sorafenib, while sorafenib was more efficacious in a model characterized by intermediate c-Met/HGF expression. MSC2156119J was not efficacious in models exhibiting low or no signs of c-Met signalling. When used in combination, MSC2156119J did not enhance the activity of sorafenib. MSC2156119J monotherapy was well tolerated while sorafenib alone and in combination with MSC2156119J induced significant body weight loss.

Overall, these data indicate that MSC2156119J may be a valuable therapeutic option for liver cancers with high levels of c-Met expression/activation.

Citation Format: Friedhelm Bladt, Andree Blaukat, Dieter Dorsch, Manja Friese-Hamim, Michael Meyring, Oliver Schadt. The c-Met inhibitor MSC2156119J effectively inhibits growth of liver cancer models. [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 925. doi:10.1158/1538-7445.AM2013-925

EMD 1214063 and EMD 1204831 constitute a new class of potent and highly selective c-Met inhibitors

PURPOSE

The mesenchymal-epithelial transition factor (c-Met) receptor, also known as hepatocyte growth factor receptor (HGFR), controls morphogenesis, a process that is physiologically required for embryonic development and tissue repair. Aberrant c-Met activation is associated with a variety of human malignancies including cancers of the lung, kidney, stomach, liver, and brain. In this study, we investigated the properties of two novel compounds developed to selectively inhibit the c-Met receptor in antitumor therapeutic interventions.

EXPERIMENTAL DESIGN

The pharmacologic properties, c-Met inhibitory activity, and antitumor effects of EMD 1214063 and EMD 1204831 were investigated in vitro and in vivo, using human cancer cell lines and mouse xenograft models.

RESULTS

EMD 1214063 and EMD 1204831 selectively suppressed the c-Met receptor tyrosine kinase activity. Their inhibitory activity was potent [inhibitory 50% concentration (IC50), 3 nmol/L and 9 nmol/L, respectively] and highly selective, when compared with their effect on a panel of 242 human kinases. Both EMD 1214063 and EMD 1204831 inhibited c-Met phosphorylation and downstream signaling in a dose-dependent fashion, but differed in the duration of their inhibitory activity. In murine xenograft models, both compounds induced regression of human tumors, regardless of whether c-Met activation was HGF dependent or independent. Both drugs were well tolerated and induced no substantial weight loss after more than 3 weeks of treatment.

CONCLUSIONS

Our results indicate selective c-Met inhibition by EMD 1214063 and EMD 1204831 and strongly support clinical testing of these compounds in the context of molecularly targeted anticancer strategies.

The αVβ3/αVβ5 integrin inhibitor cilengitide augments tumor response to melphalan isolated limb perfusion in a sarcoma model

Isolated limb perfusion (ILP) with melphalan and tumor necrosis factor (TNF)-α is used to treat bulky, locally advanced melanoma and sarcoma. However, TNF toxicity suggests a need for better-tolerated drugs. Cilengitide (EMD 121974), a novel cyclic inhibitor of alpha-V integrins, has both anti-angiogenic and direct anti-tumor effects and is a possible alternative to TNF in ILP. In this study, rats bearing a hind limb soft tissue sarcoma underwent ILP using different combinations of melphalan, TNF and cilengitide in the perfusate. Further groups had intra-peritoneal (i.p.) injections of cilengitide or saline 2 hr before and 3 hr after ILP. A 77% response rate (RR) was seen in animals treated i.p. with cilengitide and perfused with melphalan plus cilengitide. The RR was 85% in animals treated i.p. with cilengitide and ILP using melphalan plus both TNF and cilengitide. Both RRs were significantly greater than those seen with melphalan or cilengitide alone. Histopathology showed that high RRs were accompanied by disruption of tumor vascular endothelium and tumor necrosis. Compared with ILP using melphalan alone, the addition of cilengitide resulted in a three to sevenfold increase in melphalan concentration in tumor but not in muscle in the perfused limb. Supportive in vitro studies indicate that cilengitide both inhibits tumor cell attachment and increases endothelial permeability. Since cilengitide has low toxicity, these data suggest the agent is a good alternative to TNF in the ILP setting.

Abstract 1787: The c-Met inhibitors EMD 1214063 and EMD 1204831 are effective in combination with EGFR and VEGF inhibitors in NSCLC models

c-Met is a receptor tyrosine kinase that has hepatocyte growth factor as its ligand. Evidence from biochemical and human genetic studies indicate that c-Met is one of the most frequently activated tyrosine kinases in human cancer. Dysregulated c-Met signaling can result in the development of tumors highly dependent on c-Met. Furthermore, enhanced c-Met signaling is likely involved in conferring resistance to epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) inhibitors. The orally available EMD 1214063 and EMD 1204831 inhibit c-Met activity in a potent and highly selective fashion, and are currently being evaluated in cancer patients. Here we report the activity of these compounds in combination with inhibitors of EGFR and VEGF in various tumor xenograft models. EMD 1214063 was tested alone and in combination with EGFR inhibitors (erlotinib and cetuximab) in xenografts of erlotinib-resistant tumor cells, namely the lung cancer H1975 and the NCI-H441 non-small-cell lung cancer (NSCLC) cell lines. The H1975 cell line expresses moderate amounts of c-Met, and EMD 1214063 was inactive as a single agent (treatment group/control group [T/C] 78%; tumor growth delay [TGD] 2 days). Cetuximab was active with a T/C of 13% inducing a TGD of 21 days. The combination of EMD 1214063 and cetuximab was active with a T/C of α1% and a TGD of 42 days. The NCI-H441 cell line is characterized by constitutive c-Met overexpression and is sensitive to c-Met inhibitors in vivo. EMD 1214063 (100 mg/kg) was active inducing a T/C of 20%, while erlotinib alone (30 mg/kg) was not efficacious. However, the combination of EMD 1214063 with erlotinib enhanced tumor growth inhibition, induced partial tumor regression in 2/9 mice, and delayed tumor re-growth. These data are compatible with the hypothesis that cMet pathway activation confers resistance to EGFR inhibitors. We additionally investigated the combination of either EMD 1214063 or EMD 1204831 with VEGF inhibitors in NSCLC models. In NCI-H441 xenografts, EMD 1204831 produced a modest T/C (66%) at the suboptimal dose of 25 mg/kg/bid, similarly to aflibercept at 40 mg/kg (T/C 55%). In contrast, the combination of both compounds yielded a T/C of 1% with partial responses in 2/10 mice. In the EBC-1 model, treatment with EMD 1214063 (10 mg/kg) or with the antiVEGF antibody B20-4.1 (20 mg/kg) as single agents resulted in a T/C of β21% (with partial regression in 1/10 mice) and 19%, respectively. In contrast, the combination of EMD 1214063 and B20-4.1 exhibited enhanced anti-tumor activity with a T/C of −72% and partial regressions in 10/10 mice. These data support the hypothesis that EMD 1214063 or EMD 1204831 may be effective in NSCLC patients in combination with VEGF-targeting agents. In conclusion, our findings provide a rationale to evaluate the efficacy of the combination of EMD 1214063 or EMD 1204831 with EGFR and VEGF inhibitors in NSCLC patients.

Citation 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 1787. doi:1538-7445.AM2012-1787

Abstract 2786: Identification and preclinical characterization of EMD 1204831 – A selective c-Met kinase inhibitor in clinical phase 1

The involvement of the mesenchymal endothelial transition factor (c-Met) in the primary event of oncogenic transformation and the secondary ability to mediate metastatic spread has been convincingly demonstrated in preclinical and early clinical settings. The clinical benefits of c-Met kinase inhibitors with various modes of actions and selectivity profiles are currently under investigation hoping that inhibitors of c-Met might emerge as valuable cancer therapeutics in the future. During an HTS run 3-(diethylamino)propyl N-[3-[[5-(3,4-dimethoxyphenyl)-2-oxo-6H-1,3,4-thiadiazin-3-yl]methyl]phenyl]carbamate was identified as an attractive lead structure with an interesting overall profile (clogD (7.4): 2.5, S (pH 7.4): &gt;100 µg/ml, IC50 (cMet enzyme): 30 nM, IC50 (cMet A549): 800 nM) providing a valid starting point. The co-crystal structure of 1 revealed the binding mode and the essential structural features. The initial HTS hit was bound in a DFG-in conformation interacting with the main chain nitrogen atom of Met1160 within the hinge region and with the main chain nitrogen of Asp1222. After subsequent optimization of potency, efficacy, PK properties and the safety profile of thiadiazinone 1, EMD1204831 was identified as development compound. EMD1204831 is currently being investigated in a phase 1 clinical trial. The pyridazinone EMD1204831 inhibits enzymatic and cellular c-Met kinase activity with IC50 values of 12 nM and 15 nM, respectively. EMD1204831 displayed an exquisite selectivity when tested in vitro against a panel of more than 400 potential off-targets, including kinases, GPCRs, ion channels, transporters and various enzymes. EMD 1204831 demonstrated excellent anti-tumor activity in vivo in a variety of xenograft models, including U87-MG glioblastoma cells (autocrine HGF expression), TPR-Met-transformed mouse fibroblasts (oncogenic Met fusion protein) or Hs746T gastric cancer cells (c-Met gene amplification and HGF-independent activation). Depending on the particular model, complete regressions were observed with doses as low as 6 mg/kg/d administered per os. PK/PD analysis revealed efficient, dose- and time-dependent inhibition of c-Met phosphorylation, reduction of IL-8 and cyclin D1 expression as well as an induction of the cell cycle inhibitor p27. The overall profile of EMD1204831 including first time structural disclosure, some structure activity relationships, in vitro potency, selectivity profile and in-vivo data will be presented.

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 2786. doi:10.1158/1538-7445.AM2011-2786

Abstract 3622: Preclinical characterization of EMD1214063, a potent and highly selective inhibitor of the c-Met kinase in Phase I clinical trials

c-Met, the receptor for hepatocyte growth factor (HGF), is a well characterized receptor tyrosine kinase, which is crucial for cell functions, such as survival, proliferation, motility and migration. Activating point mutations of c-Met have been identified in human malignancies, including renal carcinoma and lung cancer and constitutive activation of the HGF/c-Met pathway leads to tumor development and progression in cancer animal models. In the light of these findings, c-Met has become a key target for oncology therapeutics.

In order to develop c-Met specific inhibitors, we have conducted a biochemical HTS run with the recombinant kinase domain of c-Met. This approach has enabled us to identify a new class of c-Met inhibitors. Our report will focus on pharmacological and pre-clinical data, characterising EMD1214063, a promising therapeutic candidate currently under clinical testing.

Inhibition of the c-Met kinase by EMD1214063 was potent and highly selective. In in vitro kinase reactions and binding assays, EMD1214063 at a dose of 1μM, inhibited only 5 additional kinases in a panel of more than 250 different potential off-targets more than 50%. In vitro, EMD1214063 interfered with survival, anchorage-independent growth and HGF-induced migration of tumor cells, by blocking HGF-dependent as well as constitutive phosphorylation of c-Met.

In vivo, oral administration of EMD1214063 resulted in a strong inhibition - ranging from delayed growth to complete regression - of HGF-dependent and -independent c-Met driven tumor xenografts. Such anti-tumor activity was observed at a broad dose range, suggesting that EMD1214063 has a wide therapeutic index. The inhibitor was well tolerated, as indicated by the lack of significant weight loss in treated mice. The mechanism of action of EMD1214063 was investigated in vivo in a series of PK/PD studies. Administration of a single dose of EMD1214063 induced a complete and long-lasting inhibition of c-Met phosphorylation in the tumor xenografts. Furthermore, it strongly reduced the plasma levels of tumor-derived IL-8. c-Met phosphorylation and plasma IL-8 levels decreased as a function of the drug concentration in the tumor and plasma.

Taken together, the high c-Met selectivity, potency and in vivo efficacy of EMD1214063 render this compound a very promising candidate for the treatment of patients bearing c-Met-driven tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3622.

Abstract 5777: EMD 1214063, an exquisitely selective c-Met kinase inhibitor in clinical phase 1

The role of the receptor tyrosin kinase c-Met in tumor progression, metastasis and aggressiveness has been convincingly demonstrated in preclinical and early clinical settings. Several compounds with different selectivity profiles inhibiting c-Met are currently under preclinical/clinical investigation and might emerge as valuable cancer therapeutics in the future. During an HTS run N-(3-(3,6-Dihydro-5-(3,4-dimethoxyphenyl)-2-oxo-2H-1,3,4-thiadiazin-3-ylmethyl)-phenyl)-carbaminic acid-(3-(N,N-diethylamino)-propylester) (1) was identified as an attractive lead structure with an interesting overall profile (clogD (7.4): 2.5, S (pH 7.4): &gt;100 µg/ml, IC50 (c-Met in vitro): 30 nM, IC50 (c-Met cellular): 800 nM) providing a valid starting point for lead optimization. The co-crystal structure of 1 revealed the binding mode and the essential structural features. The initial HTS hit was bound in a DFG-in conformation interacting namely with the main chain nitrogen atom of methionine 1160 within the hinge region and with the main chain nitrogen of aspartic acid 1222. After subsequent optimization of potency, efficacy, PK properties and the safety profile of thiadiazinone 1, EMD1214063 was identified as candidate for further development and is currently investigated in a phase 1 clinical trial. The pyridazinone EMD1214063 inhibits enzymatic and cellular c-Met kinase activity with IC50 values in the low nanomolar range. This compound displayed an exquisite selectivity when tested in vitro against a panel of more than 250 potential off-targets, including kinases, GPCRs, ion channels, transporters and various enzymes and demonstrated excellent anti-tumor activity in vivo in a variety of xenograft models. Depending on the particular model, complete regressions were observed with doses as low as 6 mg/kg/d administered per os. The overall profile of EMD1214063 including first time disclosure of the precise structure, synthesis, structure activity relationships, in vitro potency, selectivity profile, pharmacokinetic and in vivo data will be discussed.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5777.

Abstract B252: Identification of a new class of highly potent and selective c-Met kinase inhibitors

The role of the receptor tyrosin kinase c-Met in tumor progression and metastasis has been shown in preclinical studies and in early clinical settings. Several c-Met inhibitors with different selectivity profiles are currently in preclinical/clinical investigation and might provide effective cancer therapeutics in the future.

A biochemical HTS run using the recombinant kinase domain of c-Met enabled us to identify N-(3-(3,6-Dihydro-5-(3,4-dimethoxyphenyl)-2-oxo-2H-1,3,4-thiadiazin-3-ylmethyl)-phenyl)-carbaminic acid-(3-(N,N-diethylamino)-propylester) representing as new chemical class of kinase inhibitors. This HTS hit inhibited c-Met in vitro kinase activity and HGF-induced c-Met phosphorylation in A459 lung cancer cells with IC50 values well below 1 µM. The analysis of co-crystal structures defined the molecular requirements for potency and selectivity and guided the subsequent chemical optimization. As a result of the lead optimization process, two candidate compounds with distinct pharmacological properties were synthesized, EMD 1214063 and EMD 1204831. Both compounds are highly potent and efficient inhibitors of c-Met in vitro kinase activity and c-Met auto-phosphorylation induced in vitro by HGF stimulation or by c-Met overexpression. Both compounds displayed an exquisite selectivity profile when tested in vitro against a panel of more than 250 potential off-targets, including kinases, GPCRs, ion channels, transporters and various enzymes.

EMD 1214063 and EMD 1204831 exhibited excellent anti-tumor activity in vivo in a variety of xenograft models, including U87-MG glioblastoma cells (autocrine HGF production), TPR-Met-transformed mouse fibroblasts (oncogenic Met fusion protein) or Hs746T gastric and EBC-1 lung cancer cells (c-Met gene amplification and HGF-independent activation).

In c-Met-driven models complete regressions were observed with doses as low as 6 mg/kg/d administered per os. PK/PD analysis revealed efficient, dose- and time-dependent inhibition of c-Met phosphorylation, reduction of IL-8 and cyclin D1 expression as well as an induction of the cell cycle inhibitor p27. The pharmacodynamic effects of EMD 1214063 were longlasting and allowed various schedule variations without compromising its anti-tumor activity, while c-Met inhibition by EMD 1204831 was rather transient, allowing optimal anti-tumor activity when the compound was applied once or twice daily.

The profile of EMD 1214063 and EMD 1204831 including synthesis, structure activity relationships, X-ray structures and a comprehensive pharmacological in vitro and in vivo characterization will be presented. Furthermore, potential pharmacodynamic and predictive biomarkers will be discussed.

Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B252.

In vitro biotransformation of (R)- and (S)-thalidomide: application of circular dichroism spectroscopy to the stereochemical characterization of the hydroxylated metabolites

Circular dichroism (CD) spectroscopy was successfully used for the stereochemical characterization of the hydroxylated metabolites formed during the in vitro biotransformation of (R)- and (S)-thalidomide. Incubation extracts of the individual enantiomers were analyzed by HPLC on an achiral stationary phase combined with CD detection. The CD data of the almost enantiopure eluates of the metabolites were compared with the CD spectra quantum chemically calculated for the respective structures. The results allowed us a reliable determination of the absolute stereostructure for all of the metabolites. The chiral center of thalidomide is unaffected by the stereoselective biotransformation process. (3'R,5'R)-trans-5'-hydroxythalidomide is the main metabolite of (R)-thalidomide, which epimerizes spontaneously to give the more stable (3'S,5'R)-cis isomer. On the contrary, (S)-thalidomide is preferentially metabolized by hydroxylation in the phthalimide moiety, resulting in the formation of (S)-5-hydroxythalidomide.

Recent results of biotransformation of drugs: investigation of the in vitro biotransformation of thalidomide using a dual cyclodextrin system in capillary electrophoresis

A previously developed capillary electrophoresis method for the simultaneous separation and enantioseparation of thalidomide (TD) and its hydroxylated metabolites was extended to one additional biotransformation product. The dual chiral selector system using native beta-cyclodextrin (beta-CD) and the negatively charged sulfobutyl-beta-CD (SBE-beta-CD) was slightly modified up to a concentration of 12 mg/ml running buffer of each CD. The carrier mode in which these buffer additives transport the neutral compounds to the detector as well as the use of a polyacrylamide-coated capillary were necessary to achieve reproducible enantioseparations of all eight analytes.

Investigation of the stereoselective in vitro biotransformation of thalidomide using a dual cyclodextrin system in capillary electrophoresis

A previously developed capillary electrophoresis method for the simultaneous separation and enantioseparation of thalidomide (TD) and its hydroxylated metabolites was extended to one additional biotransformation product. The dual chiral selector system using native beta-cyclodextrin (beta-CD) and the negatively charged sulfobutyl ether-beta-CD (SBE-beta-CD) was slightly modified up to a concentration of 12 mg/mL running buffer of each CD. The carrier mode in which these buffer additives transport the neutral compounds to the detector as well as the use of a polyacrylamide-coated capillary were necessary to achieve reproducible enantioseparations of all eight analytes. The optimized method was applied to the analysis of the in vitro biotransformation of TD by rat liver microsomes. The S-enantiomer undergoes metabolism preferentially by hydroxylation in the phthalimide ring, whereas R-(+)-TD is mainly transformed to diastereomeric 5'-hydroxythalidomide (5'-OH-TD) pairs. The chiral capillary electrophoresis of incubation samples of TD enantiomers in combination with X-ray diffraction data allowed us to determine the absolute configuration of all metabolites and furthermore to follow the enantio- and stereoselective effects of metabolism in detail.

Simultaneous separation and enantioseparation of thalidomide and its hydroxylated metabolites using high-performance liquid chromatography in common-size columns, capillary liquid chromatography and nonaqueous capillary electrochromatography

The separation of thalidomide (TD) and its hydroxylated metabolites including their simultaneous enantioseparation was studied using three different polysaccharide-type chiral stationary phases (CSPs) in combination with polar organic mobile phases. Three different techniques, high-performance liquid chromatography in common-size columns, capillary LC and nonaqueous capillary electrochromatography were compared in terms of separation. As this study illustrates, polar organic mobile phases represent a valuable extension for less polar and polar aqueous-organic mobile phases in combination with polysaccharide CSPs. Chiralpak AD consisting of 25% of amylose-tris(3,5-dimethylphenylcarbamate) coated on wide-pore aminopropylsilanized silica gel exhibited higher resolving ability compared to the similar cellulose derivative (Chiralcel OD) as well as to cellulose-tris(4-methylbenzoate) (Chiralcel OJ) CSPs for this particular set of chiral analytes. Baseline separation and simultaneous enantioseparation of all three compounds could be achieved under optimized separation conditions.

Enantioseparation of thalidomide and its hydroxylated metabolites using capillary electrophoresis with various cyclodextrins and their combinations as chiral buffer additives

The separation of thalidomide (TD) and its hydroxylated metabolites including their simultaneous enantioseparation was studied in capillary electrophoresis (CE) using four different randomly substituted charged cyclodextrin (CD) derivatives, the combinations of some of them with each other, and beta-CD. TD, as well as two metabolites recently found in incubations of human liver microsomes and human blood, 5-hydroxythalidomide (5-OH-TD) and one of the diastereomeric 5'-hydroxythalidomides (5'-OH-TD), are neutral compounds. Therefore, they were resolved using charged chiral selectors in CE. Two different separation modes (normal polarity and carrier mode) and two different capillaries (fused-silica and polyacrylamide-coated) were tested. Based on the behavior of the individual CDs, their designed combinations were selected in order to improve the separation selectivity and enantioselectivity. Under optimized conditions all three chiral compounds and their enantiomers were resolved simultaneously.

Investigation of the in vitro biotransformation of R-(+)-thalidomide by HPLC, nano-HPLC, CEC and HPLC--APCI-MS

High-performance liquid chromatography (HPLC), nano-HPLC, capillary electrochromatography (CEC) and on-line HPLC-atmospheric pressure chemical ionization mass spectrometry (APCI-MS) techniques were used for the identification and detailed characterization of two new metabolites of the former sedative drug thalidomide (TD). The advantages of nano-HPLC and CEC are higher peak efficiency and a drastic decrease in the analysis time, which, together with lower sample dilution during the analyses, allowed to obtain a detection sensitivity that was comparable to HPLC with common-sized columns. Both, nano-HPLC and CEC could be realized in the commercially available capillary electrophoresis system HP3D. On-line HPLC-APCI-MS coupling is a very useful technique for the rapid identification of metabolites without any need for reference compounds.