转化医学2 医学分子生物学课件

1、转化医学 （生物标志物发现技术、疾病预测/预防、疾病诊断和治疗）分子医学概论：本节内容转化医学的概念转化医学的兴起转化医学提出的背景转化医学研究的内容实现转化医学的途径转化医学研究的结构和范例转化医学研究的内容一 分子标志物的鉴定和应用:基于各种组学方法筛选出早期诊断疾病、预测疾病(个体疾病敏感性预测)、判断药物疗效、评估患者预后的生物标志物以及药物靶标。药物靶标药物靶标的确立有助于有针对性地探索新的药物和治疗方法，提高药物筛选的成功率，缩短药物研究从实验到临床应用阶段的时间，提高研究效率。这些标志物的开发应用，将对疾病预防和诊断及治疗发挥有效的指导作用。与此相关联的产品开发将会是一个很大的产

2、业。转化医学研究的内容二 基于患者的遗传、分子生物学特征和疾病基本特征进行分子分型，以此为基础实施个体化的治疗：恶性肿瘤、心脑血管病、糖尿病等大多数慢性病是多病因疾病，其发病机制复杂，疾病异质性很大，不能采用单一方法(如同一药物、相同剂量)进行治疗。对所有患者采用一种尺度(one size fits all)的医疗时代已经过去。基于分子分型的个体化治疗将合理选择治疗方法和药物(包括剂量)，达到有效、经济和最小的毒副作用的目的。分子医学(molecular medicine)和个体化医学(personalized medicine)都是转化医学研究产生的结果。 转化医学研究的内容三 疾病治疗反应

3、和预后的评估与预测由于遗传、营养、免疫等因素的差别，同一种疾病的患者对同一种治疗方法或同一种药物的效果和预后可表现出较大的差异。在分子生物学研究的基础上，我们可利用经评估有效的生物标志物(如患者的基因分型、生化各种表型指标等)，进行患者药物敏感性和预后的预测，选择敏感的药物和适当的剂量，以提高疗效和改善预后。通过临床与实验室关联性研究(clinical-laboratory correlative studies)找出规律，阐明疾病的发生发展机制，以循证医学的原则实施医疗工作。临床前的多种模态Massoud & Gambhir，Genes & Development，2003 年Genomic

4、 /Genetic Considerations for CNS drugsGenes & the pharmaceutical enterpriseMethods for studying genesGenome-wide association studiesOpportunitiesBut now, ten years on, genetics has finally become a practical translational tool for industry Understanding of statistical issues High-fidelity high-throu

5、ghput genotyping Large repositories of population-based samples Consortia with standardized procedures Growing appreciation of the heuristic value of outliers Ever-growing number of robust validationsTarget ValidationTarget/CompoundInteractionPharmacodynamic ActivityDisease Biomarker& Disease Modifi

6、cationPatient Stratification Rare diseases have simple genetics.Common diseases have complex genetics.But now, genome-wide association studies allow efficient study of common diseases as well. Genetics The study of variation and its inheritanceIntrinsically probabilisticHeritability, segregation ana

7、lysis, linkage, associationGenomics The study of expression of all genes of an organismDeterministicTranscriptional profiling , in situ hybdrization, difference librariesMolecular BiologyThe study of molecules underlying genetics & genomicsDeterministicCloning; sequence and structural analyses; cros

8、s hybridization; site-directed mutagenesis; siRNA knockdowns; transgenic & knockout animal modelsThree distinct methodologies for three different questions Heritability estimates are always relative to the genetic and environmental factors in the population Heritability describes the population, not

9、 individuals within that populationHeritability can be estimated in controlled experiments & in population studiesPhenotype (P) = Genotype (G) + Environment (E). Var(P) = Var(G) + Var(E) + 2 Cov(G,E). If Cov(G,E) = 0. then H2 = Var(G)/ Var(P)Genetic analyses should only be undertaken if there is sig

10、nificant heritabilityUnusual high density families - dominant - point mutations (or microdeletions / duplications) in genes of major effect LinkageCommon, adult disorders without pronounced familial grouping- multiple genes of additive effect- often major environmental interactionsAssociationThe pat

11、tern of inheritance dictates the optimal genetic approachRare sporadic childhood disorders- Chromosomal rearrangements (or recessives)- Responsible genes in breakpoints or duplications/deletions SequencingFigure 1. Pedigree structure of the two Chinese families with tooth agenesis. High-density fami

12、lies ideal for linkage analysisGenomic /Genetic Considerations for CNS drugsGenes & the pharmaceutical enterpriseMethods for studying genesGenome-wide association studiesOpportunitiesLinkage & Association same general principle, different time scalesCrossovers increase with distanceLinkageAssociatio

13、n20 generations1 Score genomic DNA from a very large sample of cases & controls for a very large number of single-nucleotide polymorphisms (SNPs) Compare the frequencies among cases & controls Sites that differ significantly between cases and controls are then validated in independent samplesGenomew

14、ide association studies are based on a very simple ideaLessons learned from Genome-Wide Association Studies (GWAS,基因组相关性研究)Genome-Wide Association Studies (GWAS) work Effect sizes are usually small, so big samples needed Rigorous quality control is paramount GWAS may fail to detect certain susceptib

15、ility genesImportant to look well beyond the top few hits Collaboration is important Phenotype/selection is important Validation is criticalEvery SNP counts “Low-hanging fruit” lead to more variants Effect sizes are usually small, so big samples are needed Theory predicts that alleles of small effec

16、t are more frequent than alleles of large effect Wellcome Trust Case Control Consortium (WTCCC) GWASs of seven common diseases found per-allele odds ratios of 1.21.5 Reasonable power to detect such loci requires 2000 cases and 2000 controls Failures to replicate findings in modestly sized samples do

17、 not constitute refutation Confidence attributable to a significance level is influenced by sample size Rate of true positives increases with sample size because power to detect true effects increases Rigorous quality control is paramount Enormous data sets (samples & SNPs) in GWASs provide large op

18、portunities for spurious associations Data must be cleaned thoroughly to remove low-quality DNA samples, genotype calls & individual samples Within WTCCC the best predictor of an SNP with poor QC was a highly significant difference in genotype distributions between cases and controls - validation is

19、 criticalCollaboration is important Benefits from collaborations that increase total sample sizes , test consistency & generalizability of findings Aggressive, very early, proactive data sharing key to identification of several susceptibility loci not evident in any single study aloneStandard phenot

20、yping, threshholds for genome calls, raw data sharing Diabetes Mellitus (Types 1 & 2), coronary artery disease, ankylosing spondylitis benefited from collaborationsGenomic /Genetic Considerations for CNS drugsGenes & the pharmaceuticals enterpriseMethods for studying genesAssociation studiesOpportun

21、ities Lessons for Experimental Neurotherapeutics Learn from rare Mendelian variants of genes encoding potential drug targets (OMIM) Schizophrenia, autism, restless legs syndrome, early onset depression, bipolar disease, multiple sclerosis, Alzheimer disease, ADHD, & dyslexia are heritable common dis

22、eases tractable for GWAS Do not succumb to the temptation of relaxing diagnostic criteria to boost sample size Five Phases of ResearchPhase 1Phase 2Phase 3Phase 4Phase 5Basic ResearchMethods DevelopmentEfficacy TrialsEffectiveness TrialsDissemination ResearchFive Phase ModelBasic researchMethods dev

23、elopmentDevelopment of outcome measures, pilot studiesEfficacy trialsevaluations of health status or behavior change under scientific conditionsEffectiveness trialsevaluations under real or usual conditionsDissemination trialsExamine and evaluate conditions that promote or impede widespread useFive

24、Phase ModelPhase models assume linear progression from basic research to clinical applicationEach of five phases could work in a feedback loopEx. Phase 2 (Methods development: Development of outcome measures, pilot studies) could relate to dissemination (phase 5) which could feedback to other method

25、s of development (Phase 2)Eight Phase ModelBasic researchHypothesis developmentPilot-applied researchPrototype evaluation studiesEfficacy trialsTreatment effectiveness trialsImplementation effectiveness trialsDemonstration evaluationsPersonnel RolesResearcher-practitioner teamDoctorate level researc

26、hersPersons trained for applied workResearch planning, implementation analysis, data management, outcome analysis, reportsHealth promotion practitionersRecruitment, scheduling, maintaining field relationshipsCommunication necessary to facilitate translationTranslational ModelsFive-Phase ModelEight-P

27、hase ModelNIH Type 1 &Type 21.Basic research1. Basic research2. Hypothesis developmentType 12. Methods development3. Pilot-Applied research4. Prototype evaluation studies3. Efficacy trials5. Efficacy trials5. Effectiveness trials6. Treatment effectiveness trials7. Implementation effectiveness trials

28、Type 25. Dissemination8. Demonstration evaluationsCosts of a Translational FocusRisks undermining basic scienceDe-emphasizes technique developmentRests on accurate predictions of needRisks the creation of conflicts of interestFrequently tied to proprietary advancesHuman-subjects concernsRisks devalu

29、ing the academic enterpriseKnowledge for the sake ofConfounds academic and financial/health missionsCf. Sugarman & McKenna (2003)Early Clinical Study Designs, Emphasizing Proof-of-Concept Trials An industry perspectiveA Good Proof-of-Concept (POC) Model ?Quick to recruit relatively healthy subjectsA

30、llow a supervised setting with intense monitoring for efficacy and safetySpecific to a subtype of pain, generalizable to the entire population with that painSpecific to clinical symptoms rather than disease typeSensitive to show dose response in efficacySensitive enough to pick up side effectsObject

31、ive enough to rule out placebo response Simple enough to allow for multiple different sites without unduly increasing variabilityInclude comparator for assay sensitivityHow to Customize?“a careful sequential plan involving only a few key studies can provide sufficient basis for embarking on phase 3.

32、” (Sheiner, Clin Pharmacolog Ther 1997)“Why Math Will Rock Your World” (S. Baker, Business Week, Jan 3, 2006 coverstory) describing new ways math will be used in all sectors, including researchRudin M., Weissleder R.；药物发现和研发的分子成像技术 Nat. Rev. Drug Discov.，2，123-131，2003 年成像技术在药物发现和研发中的应用转化医学研究的结构和范例美

33、国国立卫生研究院（National institute of Health, NIH）苏格兰与 Wyeth的国际合作NIH27 InstitutesIntramural vs Extramural researchAnnual Budget: $30 billionNational Center for Medical Rehabilitation Research (NCMRR) - $77-90 millionNIH Roadmap. In Sep 2003, NIH Director Elias A. Zerhouni, M.D., laid out a series of far-re

34、aching initiatives known collectively as the NIH Roadmap for Medical Research. Designed to transform the nations medical research capabilities and speed the movement of research discoveries from the bench to the bedside. Developed with input from more than 300 nationally recognized leaders in academ

35、ia, industry, government, and the public, it provides a framework of the priorities the NIH must address to optimize its entire research portfolio (投资组合). It lays out a vision for a more efficient and productive system of medical research and identifies the most compelling opportunities in three mai

36、n areas: new pathways to discovery, research teams of the future, and re-engineering the clinical research enterprise. NIH RoadmapApproach to accelerate fundamental discovery and translation of research knowledge into effective prevention strategies and new treatments Strategic initiatives will addr

37、ess critical roadblocks and knowledge gaps that currently constrain rapid progress in biomedical research.Synergize the work of many NIH Institutes and CentersNIH RoadmapAppx. 36% of budget clinical research80% budget for extramural research, 10% budget for Intramural including 1200+ investigators C

38、linical Center model facility for translational research and trainingResult of changing health care needs and costs require changes in biomedical researchShift from acute to chronic Aging of populationPublic health challengesNIH RoadmapPerceived loss of talent in translational medicine and clinical

39、sciencesDifficulty finding scientist collaborators who can translate and clinically apply from basic scienceResearchers interested have difficulty finding facilities to apply their interestsNIH RoadmapDevelop national system of interconnected clinical research networksNIH National Electronic Clinica

40、l Trials and Research Network (NECTAR)Possible National Clinical Research Associates ProgramPatient Reported Outcomes Measurement Information System (PROMIS)Facilitate comparison among research studiesEnhance measurement precisionDevelopment of the CRCThe clinical research center (CRC) reflects the

41、parallel priorities of patient care and clinical researchProximity of research labs and patient-care units facilitates interactions between scientists, clinicians, and patient volunteersPermits clinician-scientists to work both in the lab and with patientsHelps clinicians and basic scientists learn

42、from each other in gathering places, and encourages the development of young scientists interested in clinical research. NIH Clinical Research Center242 inpatient beds, 90 day hospital bedsEvidence to Practice GapMedical journals must facilitate access and understanding of new knowledge for it to be

43、 implementedHealth researchers must communicate to researchers and practitionersHealth profession teachers should emphasize transitional processesClinical ResearchIncludes:Clinical trialsOutcomesHealth deliveryEpidemiological and psychosocial researchTranslational clinical research requires:Physicia

44、n-investigator skilled in biomedical scienceRecognition of appropriate patients to investigateClinical Research2 types of translational clinical investigatorsDisease-oriented researcher primarily working in labs or with animals, not patientsPatient-oriented translational clinical investigators (POTC

45、I)Clinical ResearchNIH and Academic Health Centers (AHC) need to support Patient-oriented translational clinical investigators (POTCIs)National bird of academic medicine may be the craneAHCs must foster collaboration in clinical researchFocus on publications needs to be expanded to include all autho

46、rs contributionsClinical Research“Cs” of clinical research:Clinical focus - interest in a disease and pts with itCollaboration with basic scientists and full time physiciansCourage to learn new techniques and approachesCooperative spousesConflict of interestCaring mentorsClinical Research ContinuumS

47、ung, NS, et al, JAMA March 12, 2003 Vol 289, No. 10Wyeth ResearchManaging Innovative Industry-Research Partnerships惠氏制药公司(Wyeth)2006年5月：苏格兰卫生部部长宣布苏格兰将与 Wyeth进行一次特殊的国际合作，共同在苏格兰启动世界上第一个转化医学合作研究中心。转化医学（TranslationalMedicine）研究致力于弥补基础实验研发与临床应用间的鸿沟，它通过研究可诊断及监测人类疾病的新参数，为开发新药品及研究新的治疗方法开辟出一条具有革命性意义的新途径。据悉，该

48、项目的总投资额接近5000万英镑。此次合作将充分聚合苏格兰和惠氏公司的专业精英力量。惠氏制药公司(Wyeth)转化医学研究针对的新参数被称为生物标志物（biomarkers），它们是新近发现的蛋白质或指示剂，可通过患者的血液样本或X光片检测出来，进而能用于观察治疗的进展以及心脏病、癌症、抑郁症、骨质疏松症等患者对治疗的反应。生物标志物还有助于探索新的治疗方法。这次合作中，该项研究也被包括在苏格兰的专科临床试验方面。这些试验将缩短新的治疗方法从实验阶段到临床阶段的时间，还可提高医护和治疗工作的质量。此外，它还能有助于根据不同的个体需要来调整处方，便于医生发现哪些药物对哪类病人更为有效，从而增强治

49、疗的针对性，确保患者得到恰当的治疗。Wyeth maintains a strong commitment to R&DR&D Spend$ Millions040080012001600200019922005240028000246810121416198995012006# CompoundsCompounds intoDevelopmentWyeth is pursuing novel targets in many difficult to treat diseasesCV/MDThrombosis ThrombosisMetabolic SyndromeAtherosclerosi

50、sNSAlzheimers DiseaseSchizophreniaStrokeMuscular DystrophyOsteoarthritisUterine FibroidsWH/MSD A significant portion of these targets are unprecedented The clinical development path is long, difficult or uncertainINFMultiple SclerosisLupus PsoriasisONCKinase InhibitorsAntibody-toxins Source: 2005 Gl

51、obal R&D Performance Metrics Programme: Industry Success Rates Report, CMR International, May 2005, p. 7Phase 1Registration1994 - 961995 - 971996 - 981997 - 991998 - 001999 - 011994 - 96Phase 31995 - 971996 - 981997 - 991998 - 001999 - 011994 - 961995 - 971996 - 981997 - 991998 - 001999 - 01Phase 20

52、%10%20%30%40%50%60%70%80%90%100%1994 - 961995 - 971996 - 981997 - 991998 - 001999 - 01Year of Entry into PhaseSuccess RateInnovation has resulted in higher clinical attrition across the industryII期，也被称为治疗探索期,去证实用来治疗特定疾病的药物的有效性,也可以与作用肯定的标准药物组或安慰剂组进行比较，观察疾病的反应情况.Lack of efficacy and safety issues are

53、the major causes of Phase 2 attritionAdapted from: DiMasi, Clin Pharmacol Ther, 2001;69(5):297-307EconomicsEfficacySafetyOther33.837.619.69% failuresNow 55%Both the proportion & absolute number of compounds that prove safe & effective in humans is declining, despite an increasing number that are saf

54、e and effective in animal modelsTarget/DiseasePlatforms: “omics” Chemical biologyImmunoassaysImagingInformation Technologiesfor integrationAnimal Biomarker FingerprintHuman Biomarker FingerprintSo how can the most promising drug candidates be identified earlier in development? Translational Medicine

55、 Animal models do not accurately predict the effects of drugs in man Discover and develop biomarkers to measure the effects of a drug in humans Better predict drug safety and efficacy in manTranslational Medicine bridges the gap between pre-clinical and clinical studies A tool to bridge the gap betw

56、een preclinical and clinical studies Allows us to understand the likely behavior of experimental medicines in humans Enables cost-effective determination of efficacy through use of biomarkersEnables cost-effective determination of safety through the use of biomarkersClinical DevelopmentDiscovery Res

57、earchTranslational medicineTraditionally, academia and pharma differ on their views of Translational MedicineAcademic viewDiscovering new drug targetsDeveloping HTP capacityDeveloping drugs for orphan diseasesAny clinical academic research“Becoming more industrial”Pharma viewResearch instituteTechno

58、logy centers (genetics, genomics, imaging) Clinical chemistry and biomarker labsCross functional teams“Becoming more academic” At Wyeth, TMed is integrated into Drug Discovery and Clinical DevelopmentTMedClinicalDiscoveryR&DBiomarkerLabBiomarker OperationsTATABiotechClinicalOperationsOutsourcing & d

59、ata managementAssay validation & sample analysisBiomarker implementation strategy & researchSample procurement & exploratory studiesCandidate biomarker identification Biomarker discovery strategy & researchThe focus of TMed has moved from technology to strategic therapeutic areasTechnology focusOmic

60、sImagingImmunoassayCV/MDINFONCTherapeutic focusA “Biomarker Roadmap” guides the research needed for a drug target and disease indicationBiomarkers are the key to success, and serve a number of purposesA biomarker is a quantifiable biological measure that correlates with a physiological, pathological