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Example of drug development. Objectives of preclinical tests. Preclinical tests helps to Evaluate its toxicity A ssess its effectiveness Propose a pharmaceutical form. Objectives (2). Preclinical studies: Select appropriate models based on target and Mode of Action These studies can:
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Objectives of preclinical tests Preclinical tests helps to • Evaluate its toxicity • Assess its effectiveness • Propose a pharmaceutical form
Objectives (2) Preclinical studies: • Select appropriate models based on target and Mode of Action • These studies can: • Provide nonclinical proof of principle regarding mechanism of action and efficacy • Guide schedule and dose escalation schemes • Provide information for selection of test species • Aid in start dose selection • Selection of investigations biomarkers : The identification of pathways involved in the mechanism of action is also essential for the selection of biomarkers of the biological activity which can be used clinically for the optimization of dosages and treatment regimens. • Justify pharmaceutical combinations • Understand pharmacodynamic properties
IMIQUALINES Lead product EAPB0203 EAPB0503 Imiquimod
Chemistry: A lead candidate was identified in Imiqualine family, a typical preclinical development program is running with major efforts on:
Chemical level Starting in laboratory synthesis scale, then synthesis in semi-pilot scale
Cancer cell lines • In vitro studies performed in cell lines, cell-free systems • Often form the basis for screening and optimization during discovery • Animal screening is too expensive for routine use • Cellular uptake and membrane transport • MDR, MRP, etc • Predictions of bioavailability and distribution • In vitro drug metabolism: • P450 isoenzyme inhibition or induction • Effects on hERG channels (prolonged QT interval risk) • Preliminary protein binding studies
The NCI-60: Assessing drug effectiveness NCI's In Vitro Cell Line Screening Project, better known as the NCI-60 analyzes the anti-cancer properties of a compound in human tumor samples from 60 different cell cultures, sometimes referred to as lines, representing leukemia, melanoma, and cancers of the lung, colon, brain, ovary, breast, prostate, and kidney. The NCI-60 project, which has been testing lines since 1990 in the Developmental Therapeutics Program of NCI's Division of Cancer Treatment and Diagnosis, screened 17,200 compounds in 2011, roughly evenly divided between natural and synthetic agents. The most promising—the "hits"—move on to further testing. Since 1990, more than 100,000 natural products have gone through the NCI screening process, driving the number of drugs in NCI's repository that have had some kind of screening process to over 400,000. There is no cost to the researcher for NCI-60 screening.
Animal models • Efficacy demonstrated in disease specific animal models: • Proof of therapeutic principle • Groundwork for clinical development planning • Evaluation of therapeutic index • Toxicity versus efficacy
Animal models (2) • Ideal Animal Model • Validity • Selectivity • Predictability • Reproducibility
Animal models for human prostate cancer • Spontaneous tumors: • Idiopathic • Carcinogen-induced • Transgenic/gene knockout animals: p53, RB, etc
Animal Pharmacokinetic models • Animal pharmacokinetics can guide dose and schedule selection • ADME data can be generated in parallel with clinical development • Preliminary evaluation of candidate biomarkers
Murine XenograftSites Subcutaneous tumor (NCI method of choice) with IP drug administration: • Intraperitoneal • Intracranial • Intrasplenic • Renal subcapsule • Site-specific (orthotopic) organ inoculation
Xenograft Advantages Disadvantages Brain tumors difficult to model Metastases rare Survival not an ideal endpoint: death from bulk of tumor, not invasion Shorter doubling times than original growth in human Less necrosis, better blood supply Difficult to maintain animals due to infection risks Ability to mimic the human tumor microenvironment is limited Many different human tumor cell lines transplantable Wide representation of most human solid tumors Allows for evaluation of therapeutic index Good correlation with drug regimens active in human lung, colon, breast, and melanoma cancers Several decades of experience
Animal models (3) There is no perfect tumor model How Predictive is the disease model in comparison to human disease ?????
Effet de l'endothélium sur la vasoconstriction induite par l'angiotensine ii dans une artère mésentérique de résistance CONTROLE INTRALUMINALE EXTRALUMINALE ANGIOTENSINE II