RESUMO
The approvals of idelalisib and duvelisib have validated PI3Kδ inhibitors for the treatment for hematological malignancies driven by the PI3K/AKT pathway. Our program led to the identification of structurally distinct heterocycloalkyl purine inhibitors with excellent isoform and kinome selectivity; however, they had high projected human doses. Improved ligand contacts gave potency enhancements, while replacement of metabolic liabilities led to extended half-lives in preclinical species, affording PI3Kδ inhibitors with low once-daily predicted human doses. Treatment of C57BL/6-Foxp3-GDL reporter mice with 30 and 100 mg/kg/day of 3c (MSD-496486311) led to a 70% reduction in Foxp3-expressing regulatory T cells as observed through bioluminescence imaging with luciferin, consistent with the role of PI3K/AKT signaling in Treg cell proliferation. As a model for allergic rhinitis and asthma, treatment of ovalbumin-challenged Brown Norway rats with 0.3 to 30 mg/kg/day of 3c gave a dose-dependent reduction in pulmonary bronchoalveolar lavage inflammation eosinophil cell count.
Assuntos
Classe I de Fosfatidilinositol 3-Quinases/química , Fatores Imunológicos/química , Pirrolidinas/química , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/metabolismo , Sítios de Ligação , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Modelos Animais de Doenças , Cães , Meia-Vida , Humanos , Fatores Imunológicos/metabolismo , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Lectinas Tipo C/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Dinâmica Molecular , Proteínas Proto-Oncogênicas c-akt/metabolismo , Pirrolidinas/metabolismo , Pirrolidinas/farmacologia , Pirrolidinas/uso terapêutico , Ratos , Ratos Wistar , Rinite Alérgica/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
PI3Kδ catalytic activity is required for immune cell activation, and has been implicated in inflammatory diseases as well as hematological malignancies in which the AKT pathway is overactive. A purine PI3Kδ inhibitor bearing a benzimidazolone-piperidine motif was found to be poorly tolerated in dog, which was attributed to diffuse vascular injury. Several strategies were implemented to mitigate this finding, including reconstruction of the benzimidazolone-piperidine selectivity motif. Structure-based design led to the identification of O- and N-linked heterocycloalkyls, with pyrrolidines being particularly ligand efficient and kinome selective, and having an improved safety pharmacology profile. A representative was advanced into a dog tolerability study where it was found to be well tolerated, with no histopathological evidence of vascular injury.
