Exam 2 lectures 14 & 15 Flashcards
(39 cards)
targeted therapies are treatments that
target specific characteristics of diseased cells
targeted therapies are generally less
harmful to normal, healthy cells
targeted therapies can be various forms:
small molecules, RNA/DNA-based oligonucleotides, antibodies, & peptides/proteins
key factors in the discovery & development of targeted therapy
- new technology
- new targets
- target validation in early development phase
- predictive models
molecular targeted drug may target at various levels:
molecular, cellular, tissue/organ, system, whole body, population
effects of targeted therapy can be
physiological
biochemical
functional
criteria for target validation
- causal relation between target & disease
- correlation with disease status
- specificity
- affinity
- mode of action (onset)
- regulation of effects
methods of target validation
- molecular/ genetic/ genomic
- biochemical/proteomic
- physiological/functional
- pharmacological/ tocicological
- population-based
testing system in target validation
- cell-free in vitro
- cell
- organ (in vitro & in vivo)
- small animals
- non-human primates
- humans
- computational biology/bioinformatics
evaluation of target validation
- qualitative (yes/no, withdrawal effect)
- quantitative ( dose-effect& dose-response relationships)
- biological effects vs. statistical signnificance
dose-effect
individual level
dose-response
group level
- most drugs are approved based on the population level
interpretation of target validation
- geno vs pheno
- in vitro vs in vivo
- animals vs humans
- healthy subjects vs patients
- other host factors (age,, sex, race)
- other limitations (dose-range)
- research tools vs drug class/entiiy
biomarkers for selection of cancer therapy: EGFR
- erlotinib (lung cancer)
- cetuximab (colon cancer)
biomarkers for selection of cancer therapy: HER2
- trastuzumab (breast cancer)
- lapatinib (breast cancer)
biomarkers for selection of cancer therapy: KRAS
cetuximab (colon cancer)
oncotype DX scoring
- for breast cancer therapy with tamoxifen
- recurrence score
- 31 high risk (benefit from chemo)
MammaPrint
- breast cancer therapy
- predict risk of metastasis
- aggressive therapy can be considered for those with poor prognosis
- for pts <61, early stage I & II
DPD (Dihydroprimidine dehydrogenase)
- drug disposition in cancer therapy
- DPD responsible for >85% 5-FU breakdown
thymidylate synthase (TS)
- drug disposition in cancer therapy
- molecular target for 5-FU
- over expression linked to drug resistance
PGX factors in targeted therapy
genetic variations in pathogens, targeted genes, in genes associated with drug metabolism/dispoition, & in signalling pathways involved in drug response & toxicity other factors (interactions & physiology/disease status)
purpose of PG testing
- provide evidence for PG variations
- improve healthcare outcome by enhancing selection & dosing of therapy
- provide rationale for stratification of subjects in clinical studies
- facilitate PG research & developing novel drugs
CYP2D6/PM
- poor response to tamoxifen
- for postmenpausal women with breast cancer can be treated with aromatoase inhibitor
- in pre-&perimenopausal women, no alternative therapy
- test can be used for monitoring response & prognosis
nocebo
negative response to treatment
- can be an effect of PG testing