{"title":"靶介导药物处置(TMDD)再访:TMDD模型的高亲和力与低亲和力近似。","authors":"Ronny Straube","doi":"10.1002/psp4.70048","DOIUrl":null,"url":null,"abstract":"<p><p>Target-mediated drug disposition (TMDD) is often associated with high-affinity binding to a target resulting in nonlinear pharmacokinetics. For large molecules, such as monoclonal antibodies, this can lead to increased clearance at sub-saturating concentrations. However, for small molecules, target binding can protect the drug from a fast systemic clearance. Here, we show that both types of behaviors can be described by simple expressions arising from a high-affinity approximation of the standard TMDD model. Interestingly, the celebrated Michaelis-Menten (MM) approximation arises in the opposite limit of low affinity and if the systemic drug clearance is sufficiently slow. Our derivation contains a previously missing factor in front of the MM constant that becomes important when target and drug-target complex elimination rates are different. As a measure of target suppression, we also derive simple expressions for the free target to baseline ratio and compare our approximations with data from large and small molecules.</p>","PeriodicalId":10774,"journal":{"name":"CPT: Pharmacometrics & Systems Pharmacology","volume":" ","pages":""},"PeriodicalIF":3.1000,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Target-Mediated Drug Disposition (TMDD) Revisited: High Versus Low-Affinity Approximations of the TMDD Model.\",\"authors\":\"Ronny Straube\",\"doi\":\"10.1002/psp4.70048\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Target-mediated drug disposition (TMDD) is often associated with high-affinity binding to a target resulting in nonlinear pharmacokinetics. For large molecules, such as monoclonal antibodies, this can lead to increased clearance at sub-saturating concentrations. However, for small molecules, target binding can protect the drug from a fast systemic clearance. Here, we show that both types of behaviors can be described by simple expressions arising from a high-affinity approximation of the standard TMDD model. Interestingly, the celebrated Michaelis-Menten (MM) approximation arises in the opposite limit of low affinity and if the systemic drug clearance is sufficiently slow. Our derivation contains a previously missing factor in front of the MM constant that becomes important when target and drug-target complex elimination rates are different. As a measure of target suppression, we also derive simple expressions for the free target to baseline ratio and compare our approximations with data from large and small molecules.</p>\",\"PeriodicalId\":10774,\"journal\":{\"name\":\"CPT: Pharmacometrics & Systems Pharmacology\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":3.1000,\"publicationDate\":\"2025-05-27\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"CPT: Pharmacometrics & Systems Pharmacology\",\"FirstCategoryId\":\"3\",\"ListUrlMain\":\"https://doi.org/10.1002/psp4.70048\",\"RegionNum\":3,\"RegionCategory\":\"医学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"PHARMACOLOGY & PHARMACY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"CPT: Pharmacometrics & Systems Pharmacology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1002/psp4.70048","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"PHARMACOLOGY & PHARMACY","Score":null,"Total":0}
Target-Mediated Drug Disposition (TMDD) Revisited: High Versus Low-Affinity Approximations of the TMDD Model.
Target-mediated drug disposition (TMDD) is often associated with high-affinity binding to a target resulting in nonlinear pharmacokinetics. For large molecules, such as monoclonal antibodies, this can lead to increased clearance at sub-saturating concentrations. However, for small molecules, target binding can protect the drug from a fast systemic clearance. Here, we show that both types of behaviors can be described by simple expressions arising from a high-affinity approximation of the standard TMDD model. Interestingly, the celebrated Michaelis-Menten (MM) approximation arises in the opposite limit of low affinity and if the systemic drug clearance is sufficiently slow. Our derivation contains a previously missing factor in front of the MM constant that becomes important when target and drug-target complex elimination rates are different. As a measure of target suppression, we also derive simple expressions for the free target to baseline ratio and compare our approximations with data from large and small molecules.