RESUMO
Adamantanyl benzamide 1 was identified as a potent P2X7R antagonist but failed to progress further due to poor metabolic stability. We describe the synthesis and SAR of a series of bioisosteres of benzamide 1 to explore improvements in the pharmacological properties of this lead. Initial efforts investigated a series of heteroaromatic bioisosteres, which demonstrated improved physicochemical properties but reduced P2X7R antagonism. Installation of bioisosteric fluorine on the adamantane bridgeheads was well tolerated and led to a series of bioisosteres with improved physicochemical properties and metabolic stability. Trifluorinated benzamide 34 demonstrated optimal physicochemical parameters, superior metabolic stability (ten times longer than lead benzamide 1), and an improved physicokinetic profile and proved effective in the presence of several known P2X7R polymorphisms.
Assuntos
Adamantano/análogos & derivados , Benzamidas/farmacologia , Antagonistas do Receptor Purinérgico P2X/farmacologia , Receptores Purinérgicos P2X7/efeitos dos fármacos , Adamantano/farmacologia , Animais , Benzamidas/síntese química , Benzamidas/química , Benzamidas/farmacocinética , Biotransformação , Avaliação Pré-Clínica de Medicamentos , Estabilidade de Medicamentos , Humanos , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Oxirredução , Polimorfismo de Nucleotídeo Único , Antagonistas do Receptor Purinérgico P2X/síntese química , Antagonistas do Receptor Purinérgico P2X/química , Antagonistas do Receptor Purinérgico P2X/farmacocinética , Ratos , Receptores Purinérgicos P2X7/genética , Relação Estrutura-AtividadeRESUMO
The purpose of this work was to use various molecular imaging techniques to non-invasively assess GSK2849330 (anti HER3 ADCC and CDC enhanced 'AccretaMab' monoclonal antibody) pharmacokinetics and pharmacodynamics in human xenograft tumor-bearing mice. Immuno-PET biodistribution imaging of radiolabeled 89Zr-GSK2849330 was assessed in mice with HER3 negative (MIA-PaCa-2) and positive (CHL-1) human xenograft tumors. Dose dependency of GSK2849330 disposition was assessed using varying doses of unlabeled GSK2849330 co-injected with 89Zr-GSK2849330. In-vivo NIRF optical imaging and ex-vivo confocal microscopy were used to assess the biodistribution of GSK2849330 and the HER3 receptor occupancy in HER3 positive xenograft tumors (BxPC3, and CHL-1). Ferumoxytol (USPIO) contrast-enhanced MRI was used to investigate the effects of GSK2849330 on tumor macrophage content in CHL-1 xenograft bearing mice. Immuno-PET imaging was used to monitor the whole body drug biodistribution and CHL-1 xenograft tumor uptake up to 144 hours post injection of 89Zr-GSK2849330. Both hepatic and tumor uptake were dose dependent and saturable. The optical imaging data in the BxPC3 xenograft tumor confirmed the tumor dose response finding in the Immuno-PET study. Confocal microscopy showed a distinguished cytoplasmic punctate staining pattern within individual CHL-1 cells. GSK2849330 inhibited tumor growth and this was associated with a significant decrease in MRI signal to noise ratio after USPIO injection and with a significant increase in tumor macrophages as confirmed by a quantitative immunohistochemistry analysis. By providing both dose response and time course data from both 89Zr and fluorescently labeled GSK2849330, complementary imaging studies were used to characterize GSK2849330 biodistribution and tumor uptake in vivo. Ferumoxytol-enhanced MRI was used to monitor aspects of the immune system response to GSK2849330. Together these approaches potentially provide clinically translatable, non-invasive techniques to support dose optimization, and assess immune activation and anti-tumor responses.
Assuntos
Anticorpos Monoclonais Humanizados/farmacocinética , Anticorpos Monoclonais/farmacocinética , Macrófagos/imunologia , Compostos Radiofarmacêuticos/farmacocinética , Receptor ErbB-3/imunologia , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/uso terapêutico , Linhagem Celular Tumoral , Feminino , Óxido Ferroso-Férrico/química , Humanos , Imuno-Histoquímica , Marcação por Isótopo , Macrófagos/citologia , Macrófagos/patologia , Camundongos , Camundongos Nus , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Radioisótopos , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/uso terapêutico , Receptor ErbB-3/metabolismo , Distribuição Tecidual , Transplante Heterólogo , Zircônio/químicaRESUMO
Neuroinflammation, in particular activation of microglia, is thought to play an important role in the progression of neurodegenerative diseases. In activated microglia, the purinergic P2X7 receptor is upregulated. A-740003, a highly affine and selective P2X7 receptor antagonist, is a promising candidate for the development of a radiotracer for imaging of neuroinflammation by positron emission tomography. For this purpose, [(11)C]A-740003 was synthesised and evaluated in vivo with respect to both tracer metabolism and biodistribution. In plasma, a moderate metabolic rate was seen. In healthy rat brain, only marginal uptake of [(11)C]A-740003 was observed and, therefore, metabolites in brain could not be determined. Whether the minimal brain uptake is due to the low expression levels of the P2X7 receptor in healthy brain or to limited transport across the blood-brain barrier has yet to be elucidated.
Assuntos
Acetamidas/síntese química , Encéfalo/efeitos dos fármacos , Antagonistas do Receptor Purinérgico P2X/síntese química , Quinolinas/síntese química , Compostos Radiofarmacêuticos/síntese química , Acetamidas/farmacocinética , Animais , Encéfalo/patologia , Isótopos de Carbono/química , Avaliação Pré-Clínica de Medicamentos , Masculino , Antagonistas do Receptor Purinérgico P2X/farmacocinética , Quinolinas/farmacocinética , Compostos Radiofarmacêuticos/farmacocinética , Ratos , Ratos Wistar , Distribuição TecidualRESUMO
RG7356 is a humanized antibody targeting the constant region of CD44. RG7356 was radiolabeled with (89)Zr for preclinical evaluations in tumor xenograft-bearing mice and normal cynomolgus monkeys to enable study of its biodistribution and the role of CD44 expression on RG7356 uptake. Studies with (89)Zr-RG7356 were performed in mice bearing tumor xenografts that differ in the level of CD44 expression (CD44(+) or CD44(-)) and RG7356 responsiveness (resp or non-resp): MDA-MB-231 (CD44(+), resp), PL45 (CD44(+), non-resp) and HepG2 (CD44(-), non-resp). Immuno-PET whole body biodistribution studies were performed in normal cynomolgus monkeys to determine normal organ uptake after administration of a single dose. At 1, 2, 3, and 6 days after injection, (89)Zr-RG7356 uptake in MDA-MB-231 (CD44(+), resp) xenografts was nearly constant and about 9 times higher than in HepG2 (CD44(-), non-resp) xenografts (range 27.44 ± 12.93 to 33.13 ± 7.42% ID/g vs. 3.25 ± 0.38 to 3.90 ± 0.58% ID/g). Uptake of (89)Zr-RG7356 was similar in MDA-MB-231 (CD44(+), resp) and PL45 (CD44(+), non-resp) xenografts. Studies in monkeys revealed antibody uptake in spleen, salivary glands and bone marrow, which might be related to the level of CD44 expression. (89)Zr-RG7356 uptake in these normal organs decreased with increasing dose levels of unlabeled RG7356. (89)Zr-RG7356 selectively targets CD44(+) responsive and non-responsive tumors in mice and CD44(+) tissues in monkeys. These studies indicate the importance of accurate antibody dosing in humans to obtain optimal tumor targeting. Moreover, efficient binding of RG7356 to CD44(+) tumors may not be sufficient in itself to drive an anti-tumor response.
Assuntos
Anticorpos Monoclonais Humanizados/administração & dosagem , Carcinoma/terapia , Receptores de Hialuronatos/metabolismo , Imunoterapia/métodos , Radioisótopos/química , Zircônio/química , Animais , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/química , Carcinoma/imunologia , Linhagem Celular Tumoral , Ensaios Clínicos Fase I como Assunto , Avaliação Pré-Clínica de Medicamentos , Humanos , Receptores de Hialuronatos/genética , Receptores de Hialuronatos/imunologia , Macaca fascicularis , Camundongos , Distribuição Tecidual , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
During the last decade, the discovery of critical tumor targets has boosted the design of targeted therapeutic agents with monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs) receiving most of the attention. Immuno-positron emission tomography (immuno-PET) and TKI-PET, the in vivo tracking and quantification of mAbs and TKIs biodistribution with PET, are exciting novel options for better understanding of the in vivo behavior and efficacy of these targeted drugs in individual patients and for more efficient drug development. Very recently, current good manufacturing practice compliant procedures for labeling of mAbs with positron emitters have been described, as well as the preparation of some radiolabeled TKIs, while the first proof of principle studies has been performed in patients. In this review, technical developments in immuno-PET and TKI-PET are described, and their clinical potential is discussed. An overview is provided for the most appealing preclinical immuno-PET and TKI-PET studies, as well as the first clinical achievements with these emerging technologies.