AMG-517

AMG-517 is an antagonist of TRPV1 channel with IC50 value of 1-2 nM [1].
TRP1, transient receptor potential cation channel subfamily V member 1, is a subfamily of the transient receptor potential protein group and plays an important role in detecting and regulating body temperature or sensing pain. TRPV1 can be activated by diverse stimuli, including several ingredients of the inflammatory soup which leads to a painful, burning sensation. It is reported that TRPV1 channel may play a pivotal role in many diseases like SIRS [1] [2].
AMG-517 is a TRPV1 antagonist. When tested with stable CHO cell lines expressing TRPV1, treated with AMG-517 inhibited the activation of TRPV1 [1].
In C57BL/6 mice with SIRS induced by LPS, pretreatment with AMG-517 (210 µg/kg) markedly decreased the survival rate and increased the risk of mortality [2]. When tested with Trpv1-/- mice, intraperitoneally treated with AMG-517 (256 nmol/kg) inhibited TRPV1 with inducing hyperthermia in a dose-dependent manner [3]. In capsaicin-induced flinch male Sprague-Dawley rats, oral administration of AMG-517 markedly decreased the number of flinches in a dose-dependent manner [1].
References:
[1].Gavva, N.R., et al., Repeated administration of vanilloid receptor TRPV1 antagonists attenuates hyperthermia elicited by TRPV1 blockade. J Pharmacol Exp Ther, 2007. 323(1): p. 128-37.
[2].Wanner, S.P., et al., Aging reverses the role of the transient receptor potential vanilloid-1 channel in systemic inflammation from anti-inflammatory to proinflammatory. Cell Cycle, 2012. 11(2): p. 343-9.
[3].Garami, A., et al., Contributions of different modes of TRPV1 activation to TRPV1 antagonist-induced hyperthermia. J Neurosci, 2010. 30(4): p. 1435-40.

Application of automated dried blood spot sampling and LC-MS/MS for pharmacokinetic studies of AMG 517 in rats.[Pubmed:22011182]

Bioanalysis. 2011 Oct;3(20):2349-56.

BACKGROUND: The use of dried blood spot (DBS) sampling technique is of particular interest for drug discovery pharmacokinetic studies due to the small blood volume requirement. In addition, automated blood sampling is an attractive approach for rat pharmacokinetic studies as animal handling work is minimized. The goal of this study was to use an automated DBS sampler for automated blood collection and spotting onto DBS paper for pharmacokinetic studies in rats. AMG 517, a potent and selective vanilloid receptor antagonist, was dosed to rats (n = 3) intravenously and blood samples were collected at nine time points over a 24 h period using the automated DBS sampler. After drying, storage and shipment, the DBS samples were extracted and analyzed by LC-MS/MS. RESULTS: The developed bioanalytical method for the analysis of DBS samples had good accuracy and precision within the context of a discovery, non-GLP analysis. The concentration-time data and pharmacokinetic parameters generated from automated spotted samples were very similar to those derived from manually spotted DBS samples. The manual DBS data were also comparable to plasma data after correction for blood-to-plasma ratio. CONCLUSION: The automated DBS sampling is a promising technique for rodent pharmacokinetic studies and will improve the efficiency and quality of DBS sampling.

Investigation of Phase Mixing in Amorphous Solid Dispersions of AMG 517 in HPMC-AS Using DSC, Solid-State NMR, and Solution Calorimetry.[Pubmed:26457879]

Mol Pharm. 2015 Nov 2;12(11):4115-23.

Intimate phase mixing between the drug and the polymer is considered a prerequisite to achieve good physical stability for amorphous solid dispersions. In this article, spray dried amorphous dispersions (ASDs) of AMG 517 and HPMC-as were studied by differential scanning calorimetry (DSC), solid-state NMR (SSNMR), and solution calorimetry. DSC analysis showed a weakly asymmetric (DeltaTg approximately 13.5) system with a single glass transition for blends of different compositions indicating phase mixing. The Tg-composition data was modeled using the BKCV equation to accommodate the observed negative deviation from ideality. Proton spin-lattice relaxation times in the laboratory and rotating frames ((1)H T1 and T1rho), as measured by SSNMR, were consistent with the observation that the components of the dispersion were in intimate contact over a 10-20 nm length scale. Based on the heat of mixing calculated from solution calorimetry and the entropy of mixing calculated from the Flory-Huggins theory, the free energy of mixing was calculated. The free energy of mixing was found to be positive for all ASDs, indicating that the drug and polymer are thermodynamically predisposed to phase separation at 25 degrees C. This suggests that miscibility measured by DSC and SSNMR is achieved kinetically as the result of intimate mixing between drug and polymer during the spray drying process. This kinetic phase mixing is responsible for the physical stability of the ASD.

Application of twin screw extrusion to the manufacture of cocrystals: scale-up of AMG 517-sorbic acid cocrystal production.[Pubmed:25406487]

Faraday Discuss. 2014;170:235-49.

The application of twin screw extrusion (TSE) in the scale-up of cocrystal production was investigated by using AMG 517-sorbic acid as a model system. Extrusion parameters that influenced conversion to the cocrystal such as temperature, feed rate and screw speed were investigated. Extent of conversion to the cocrystal was found to have a strong dependence on temperature and a moderate dependence on feed rate and screw speed. Cocrystals made by the TSE process were found to have superior mechanical properties than solution grown cocrystals. Additionally, moving to a TSE process eliminated the need for solvent.

Isothermal microcalorimetry to investigate the phase separation for amorphous solid dispersions of AMG 517 with HPMC-AS.[Pubmed:23574401]

Mol Pharm. 2013 May 6;10(5):1949-57.

Understanding the crystallization kinetics of an amorphous drug is critical for the development of an amorphous solid dispersion (ASD) formulation. This paper examines the phase separation and crystallization of the drug AMG 517 in ASDs of varying drug load at various conditions of temperature and relative humidity using isothermal microcalorimetry. ASDs of AMG 517 in hydroxypropyl methylcellulose acetate succinate (HPMC-AS) were manufactured using a Buchi 290 mini spray dryer system. ASDs were characterized using modulated differential scanning calorimetry (mDSC) and scanning electron microscopy (SEM) prior to isothermal microcalorimetry evaluation, and crystallinity was measured using (19)F solid state nuclear magnetic resonance spectroscopy (SSNMR), before and after crystallization. The crystallization of ASDs of AMG 517 in HPMC-AS was significantly slowed by the presence of HPMC-AS polymer, indicating enhanced physical stability for the ASD formulations. A two-phase crystallization was observed by isothermal microcalorimetry at temperatures near the glass transition temperature (Tg), indicating a drug-rich phase and a miscible ASD phase. (19)F SSNMR showed that only partial crystallization of the drug occurred for the ASDs, suggesting a third phase which did not crystallize, possibly representing a thermodynamically stable, soluble component. Isothermal microcalorimetry provides important kinetic data for monitoring crystallization of the drug in the ASDs and, together with (19)F SSNMR, suggests a three-phase ASD system for AMG 517 in HPMC-AS.

Novel vanilloid receptor-1 antagonists: 2. Structure-activity relationships of 4-oxopyrimidines leading to the selection of a clinical candidate.[Pubmed:17585750]

J Med Chem. 2007 Jul 26;50(15):3515-27.

A series of novel 4-oxopyrimidine TRPV1 antagonists was evaluated in assays measuring the blockade of capsaicin or acid-induced influx of calcium into CHO cells expressing TRPV1. The investigation of the structure-activity relationships in the heterocyclic A-region revealed the optimum pharmacophoric elements required for activity in this series and resulted in the identification of subnanomolar TRPV1 antagonists. The most potent of these antagonists were thoroughly profiled in pharmacokinetic assays. Optimization of the heterocyclic A-region led to the design and synthesis of 23, a compound that potently blocked multiple modes of TRPV1 activation. Compound 23 was shown to be effective in a rodent "on-target" biochemical challenge model (capsaicin-induced flinch, ED50 = 0.33 mg/kg p.o.) and was antihyperalgesic in a model of inflammatory pain (CFA-induced thermal hyperalgesia, MED = 0.83 mg/kg, p.o.). Based on its in vivo efficacy and pharmacokinetic profile, compound 23 (N-{4-[6-(4-trifluoromethyl-phenyl)-pyrimidin-4-yloxy]-benzothiazol-2-yl}-acetami de; AMG 517) was selected for further evaluation in human clinical trials.

Repeated administration of vanilloid receptor TRPV1 antagonists attenuates hyperthermia elicited by TRPV1 blockade.[Pubmed:17652633]

J Pharmacol Exp Ther. 2007 Oct;323(1):128-37.

Capsaicin, the active ingredient in some pain-relieving creams, is an agonist of a nonselective cation channel known as the transient receptor potential vanilloid type 1 (TRPV1). The pain-relieving mechanism of capsaicin includes desensitization of the channel, suggesting that TRPV1 antagonism may be a viable pain therapy approach. In agreement with the above notion, several TRPV1 antagonists have been reported to act as antihyperalgesics. Here, we report the in vitro and in vivo characterization of a novel and selective TRPV1 antagonist, N-(4-[6-(4-trifluoromethyl-phenyl)-pyrimidin-4-yloxy]-benzothiazol-2-yl)-acetamid e I (AMG 517), and compare its pharmacology with that of a closely related analog, tert-butyl-2-(6-([2-(acetylamino)-1,3-benzothiazol-4-yl]oxy)pyrimidin-4-yl)-5-(tr ifluoromethyl)phenylcarbamate (AMG8163). Both AMG 517 and AMG8163 potently and completely antagonized capsaicin, proton, and heat activation of TRPV1 in vitro and blocked capsaicin-induced flinch in rats in vivo. To support initial clinical investigations, AMG 517 was evaluated in a comprehensive panel of toxicology studies that included in vivo assessments in rodents, dogs, and monkeys. The toxicology studies indicated that AMG 517 was generally well tolerated; however, transient increases in body temperature (hyperthermia) were observed in all species after AMG 517 dosing. To further investigate this effect, we tested and showed that the antipyretic, acetaminophen, suppressed the hyperthermia caused by TRPV1 blockade. We also showed that repeated administration of TRPV1 antagonists attenuated the hyperthermia response, whereas the efficacy in capsaicin-induced flinch model was maintained. In conclusion, these studies suggest that the transient hyperthermia elicited by TRPV1 blockade may be manageable in the development of TRPV1 antagonists as therapeutic agents. However, the impact of TRPV1 antagonist-induced hyperthermia on their clinical utility is still unknown.

Novel vanilloid receptor-1 antagonists: 3. The identification of a second-generation clinical candidate with improved physicochemical and pharmacokinetic properties.[Pubmed:17585751]

J Med Chem. 2007 Jul 26;50(15):3528-39.

Based on the previously reported clinical candidate, AMG 517 (compound 1), a series of related piperazinylpyrimidine analogues were synthesized and evaluated as antagonists of the vanilloid 1 receptor (VR1 or TRPV1). Optimization of in vitro potency and physicochemical and pharmacokinetic properties led to the discovery of (R)-N-(4-(6-(4-(1-(4-fluorophenyl)ethyl)piperazin-1-yl)pyrimidin-4-yloxy)benzo[d] thiazol-2-yl)acetamide (16p), a potent TRPV1 antagonist [rTRPV1(CAP) IC50 = 3.7 nM] with excellent aqueous solubility (>or=200 microg/mL in 0.01 N HCl) and a reduced half-life (rat t1/2 = 3.8 h, dog t1/2 = 2.7 h, monkey t1/2 = 3.2 h) as compared to AMG 517. In addition, compound 16p was shown to be efficacious at blocking a TRPV1-mediated physiological response in vivo (ED50 = 1.9 mg/kg, p.o. in the capsaicin-induced flinch model in rats) and was also effective at reducing thermal hyperalgesia induced by complete Freund's adjuvant in rats (MED = 1 mg/kg, p.o). Based on its improved overall profile, compound 16p (AMG 628) was selected as a second-generation candidate for further evaluation in human clinical trials as a potential new treatment for chronic pain.