Clinical ef

clinical fellowship programme临床研修计划：培养医学专业临床技能的关键步骤引言：在现代医学领域，持续的进修和专业培训在成为一名合格的临床医生中扮演着至关重要的角色。

临床研修计划是一项通过提供实践和理论培训，以进一步发展医学专业临床技能的系统化培训计划。

本文将一步一步回答有关临床研修计划的一些关键问题，如何选择一个合适的计划，以及它如何帮助医生在临床实践中取得成功。

一、什么是临床研修计划？临床研修计划是为医学专业人士提供的一种结构化培训计划，旨在通过提供实践和理论培训来增强其临床技能和知识。

这些计划通常由医学院、大学、医疗机构或专业协会提供，以确保医学专业人士能够在特定领域获得高质量的培训。

二、如何选择一个合适的临床研修计划？选择一个合适的临床研修计划是医学专业人士职业发展的重要决策。

以下是选择一个合适的临床研修计划的关键步骤：1. 确定专业发展目标：首先，医学专业人士应该确定他们希望在哪个领域深入研究和发展。

这可能是内科、外科、儿科等领域。

2. 研究可用的计划：一旦确定专业发展目标，医学专业人士应该研究可用的临床研修计划。

这可以通过搜索医学院、大学、医疗机构或专业协会的网站来进行。

3. 评估计划的质量：在选择计划之前，医学专业人士应该评估计划的质量。

这可以通过查看计划的课程设置、资格要求、教学团队的经验和计划的声誉等方面来完成。

4. 考虑可用资源：医学专业人士还应该考虑计划提供的资源，如实践机会、研究设备、实验室设施等。

这些资源将对他们在临床实践中的学习和发展产生重要影响。

5. 考虑时间和金钱投资：最后，医学专业人士还应该考虑投入计划所需的时间和金钱。

这包括计划的持续时间、培训费用和可能的个人成本，如住宿和生活费。

三、临床研修计划如何帮助医生在临床实践中取得成功？临床研修计划对医学专业人士在临床实践中取得成功起着重要的作用。

以下是它如何帮助医生提高临床技能和知识：1. 实践机会：临床研修计划为医学专业人士提供了丰富的实践机会，使他们能够在真实的临床场景中应用所学知识。

Clinical and Experimental Allergy,1996,Volume26,pages1228–1231 EDITORIALSublingual immunotherapyThe concept of treating allergic diseases by oral ingestion of allergens dates back to the beginning of this century[1],and may be classified into two categories:(a)oral immunother-apy,i.e.swallowing the extract(either in the form of aqueous extract or by ingesting powdered extracts in enter-osoluble capsules);and(b)sublingual immunotherapy,i.e. retaining the extract for a defined period of time in the mouth.Sublingual immunotherapy could be subdivided into either exclusively sublingual therapy,i.e.allowing absorp-tion of the extract from the oral mucous membranes and then spitting out the extracts,or a combined sublingual/oral therapy whereby the extract is subsequently swallowed.The scientific basis for oral immunotherapy is based on the high number of immunocompetent cells which are located in intestinal lymph nodes[2].The absolute prerequisite for sublingual immunotherapy is the penetration of sufficient amounts of allergens through the oral mucosa.Based on studies on exclusively sublingual immunotherapy like the study in this issue by Quirino et al.[3],one might question the absorption of allergen through the oral mucosa,as these studies were not able to demonstrate any increase in specific IgG.The role of specific IgG as being directly involved in reducing the release of allergic mediators from mast cells and thereby in the clinical efficacy of injection immuno-therapy is unlikely[4],but on the other hand,an increase in IgG indicates activation of immunocompetent cells and thereby a systemic administration of a significant amount of allergen.Experiments with radiolabelled allergen extracts(Canonica,personal communication)do not indi-cate any absorption in the oral cavity,thereby raising doubt about the rationale for this form of allergen administration. The degradation of aqueous allergen extract before reaching the small intestine results in reducing the allergenicity by 90%,as estimated by RAST-inhibition[5].The degradation into peptides and subsequent stimulation of immunocompe-tent cells with these peptides might,however,represent an advantage in the form of an unintended peptide treatment [6].Documentation about the clinical efficacy of sublingual (or sublingual/oral)immunotherapy includes nine pub-lished papers concerning placebo-controlled double-blind studies.The validation of the quality of the papers is hampered by a great variability in the amount of allergen extract administered,the duration of the treatment,and the criteria for concluding a clinical efficacy(Table1).Six of the nine studies evaluate the efficacy after less than1year of treatment in spite of the possibility that a longer duration of treatment might improve the clinical efficacy.The amount of allergen extract administered also differs over a wide range,from homeopathic doses used in the study by Scadding[7],to cumulative doses twice those used in injection immunotherapy[3].The greatest dilemma in elucidating the clinical value of sublingual immunotherapy is related to the criteria used for conclud-ing a clinical efficacy.It is my opinion that the only parameters indicating efficacy are a reduction in symp-toms and/or drug intake,that from a clinical point of view significantly reduce the morbidity of allergic disorders[8]. Changes in immunological parameters and challenge tests may be of interest in elucidating mechanisms,but cannot constitute clinical evaluation[9].The optimal study design for investigating clinical efficacy includes a pre-treatment monitoring of symptoms and drug score for a season[9].This gives the advantage of elucidating the clinical relevance of allergen exposure in eliciting symp-toms(critically important for the indication of immu-notherapy),and represents the only possible way of ensuring an equal balance of disease severity in the active and control groups.The study by Quirino et al.[3]is a carefully designed (double-blind,double-dummy)study,following inter-national guidelines for‘good clinical practice’by pre-treatment monitoring of disease severity and evaluating clinical efficacy by a reduction in symptoms and drug intake,comparing the efficacy of sublingual immuno-therapy with the traditional injection treatment.The con-clusions of the study would have been improved by including a placebo group(to investigate the variation in symptom and drug scores not caused by active treatment), but comparison with a well-documented treatment is acceptable in elucidating efficacy.The magnitude of the clinical improvement is also important.It is of course critical to document a statistically significant dif-ference between the active group and the placebo group, but‘P-values’do not per se guarantee the applicability of a specified treatment.A10%reduction in drug intake might be statistically significant but for the patient clinically irrelevant.When optimally performed,traditional injection immu-notherapy has a documented clinical capacity to reduce,in actively treated patients,symptoms and drug intake to about 20%of symptoms and drug score of the placebo-treated group[10].In the Quirino study[3],the average efficacy implies a reduction of50%in symptoms and drug score in the treatment grass pollen season as compared to the pre-treatment season(being exposed to identical allergen load?).The lack of difference between the injection group1228#1996Blackwell Science LtdSublingual immunotherapy1229#1996Blackwell Science Ltd,Clinical and Experimental Allergy ,26,1228–1231T a b l e 1.P u b l i s h e d p l a c e b o c o n t r o l l e d d o u b l e b l i n d s u b l i n g u a l i m m u n o t h e r a p y s t u d i e sN o .o f p a t i e n t s A l l e r g e n D u r a t i o n o f A l l e r g e n R e f e r e n c e D i s e a s eA c t i v e /P l a c e b o e x t r a c t t r e a t m e n t d o s e *C l i n i c a l e f fic a c y yS i d e e f f e c t sz S c a d d i n g 1986R h i n i t i s 20M i t e s 2w e e k s L o w d o s eS u b j e c t i v e N o V a n N i e k e r k 1987R h i n i t i s 19/2114g r a s s e s 2y e a r s §?#S y m p t o m s N o s e v e r e?D r u g s T a r i 1990R h i n i t i s /A s t h m a30/28M i t e s 18m o n t h s M D 3.75B U#S y m p t o m s 32e p i s o d e s $D r u g s 3s e v e r e a s t h m aN o v e m b r e 1991A s t h m a 13M i t e s 1y e a r M D 3750U N?S y m p t o m s #D r u g s 23%N e l s o n 1993R h i n i t i s /A s t h m a20/21C a t 105d a y sM D 100,000A U N oA P C D 4,500,000A U N o s e v e r e S a b b a h 1994R h i n i t i s29/295g r a s s e s 17w e e k s M D 100I R#S y m p t o m s A 34%#D r u g s P 24%C a s a n o v a s 1994R h i n i t i s9/6O l e a 2m o n t h s M D 0.5H E P#A s t h m a s y m p t o m sA 33%P 33%T r o i s e 1995R h i n i t i s15/16P a r i e t a r i a 10m o n t h sM D 1.25B U $S y m p t o m s A 7%C D 105B U #D r u g s c o r e P 6%F e l i z i a n i 1995R h i n i t i s /A s t h m a18/165g r a s s e s 3½m o n t h sM D 25B U#S y m p t o m s N o s e v e r e#D r u g s*A l l e r g e n d o s e s a r e s t a t e d a s m a x i m a l d o s e (M D )a n d i f p o s s i b l e a s c u m u l a t i v e d o s e (C D ).T h e d i f f e r e n t p o t e n c y u n i t s m a k e s c o m p a r i s o n i m p o s s i b l e .yC l i n i c a l e f fic a c y i s b a s e d o n a s t a t i s t i c a l l y s i g n i fic a n t r e d u c t i o n i n s y m p t o m s a n d /o r d r u g s .z S i d e e f f e c t s c a l c u l a t e d a s p e r c e n t a g e o f p a t i e n t s e x p e r i e n c i n g s y s t e m i c s i d e e f f e c t s (Aa c t i v e g r o u p ;P p l a c eb o g r o u p ),a n d t h e s e v e r i t y o f s i d e e f f ec t s .§1s t y e a r p l a c e b o -c o n t r o l l ed d o u b le -b l i n d ,2n d y e a r o p e n s t u d y .and the sublingual group might,by sceptics,be interpreted purely as a placebo effect,although a placebo effect of this magnitude is rare.The inclusion of a placebo group would have solved that problem!The major objection to injection immunotherapy is the frequency of systemic side effects[9].In sublingual immu-notherapy,the most frequently noted side effect is related to the exposure of the oral mucosa to the allergen extract,i.e. itching and irritation.Nasal and intestinal symptoms are rarely reported.Urticaria and asthma have been elicited,but no cases of anaphylaxis have been described.In contrast to most other injection immunotherapy studies,the parenteral administration of grass pollen in the study by Quirino et al.[3]did not induce systemic side effects,and only a few minor local side effects were reported.The complete lack of systemic side effects and the limited local reactions might, by chance,be caused by the limited number of patients,but the use of low-potency extracts could also be the explana-tion(the Abello`biological units do not give any information on the amount of major grass pollen allergen).A higher maximum administered single dose in injection immu-notherapy compared to sublingual immunotherapy(and vice versa for cumulative doses)might also explain the difference in systemic side effects.The actual data from the Quirino study[3]related to this issue are:injection20BU; sublingual 6BU.A study exposing patients to identical allergen doses would be of interest.In conclusion,as long as injection immunotherapy is still considered controversial in spite of the clinical documenta-tion for efficacy(and side effects),one has to be extremely cautious in recommending sublingual/oral immunotherapy for routine treatment of allergic diseases.Of the nine published studies,one[11]has not been able to document efficacy of cat sublingual immunotherapy.The Scadding study[7]could,due to the homeopathic dose of allergen and exceptional study design,be excluded from studies included in the evaluation of efficacy.Two studies(using mite and olea allergens)include too few patients to allow conclusions to be drawn[12,13].There is only one study which includes an acceptable number of patients using mite allergen [14]with some efficacy(reduced symptoms),and one Parietaria and three grass pollen studies showing efficacy [15,16,17,18].I agree with the conclusion of Quirino et al.[3]that‘the safety of an alternative therapy is a real advantage only if it is not counterbalanced by a loss of clinical efficacy’.In my opinion,sublingual immunotherapy is without doubt a safe treatment,but the clinical efficacy—especially in relation to injection immunotherapy—is only documented by a few studies and only for mite,Parietaria and grass allergens. Before recommending this alternative specific treatment for routine use,we need more documentation of efficacy(and the magnitude of the reduction in symptoms and drugs)both in comparison to placebo and in relation to injection immunotherapy.References1Black JH.The oral administration of pollen.J Lab Clin Med 1927;12:1156.2Mestecky J.The common mucosal immune system and current strategies for induction of immune responses in external secretions.J Clin Immunol1987;7:265–76.3Quirino T,Iemoli E,Siciliani E,Parmiani S,Milazzo F.Sublingual versus injective immunotherapy in grass pollen allergic patients:a double blind(double dummy)study.Clin Exp Allergy1996;x:y–y.4Malling H-J,Djurup R.Diagnosis and immunotherapy of mould allergy.VII.IgG subclass response and relation to the clinical efficacy of immunotherapy with Cladosporium.Allergy1987;43:60–70.5Igea JM,Cuevas M,Lazaro M,Quirce S,Cuesta J.Suscept-ibility of a grass-pollen oral immunotherapy extract to the saliva and gastricfluid digestive process.Allergol Immuno-pathol1994;22:55–9.6Wallner BP,Gefter ML.Immunotherapy with T-cell-reactive peptides derived from allergens.Allergy1994;49: 302-8.7Scadding K,Brostoff J.Low dose sublingual therapy in patients with allergic rhinitis due to dust mite.Clin Allergy 1986;16:483–91.8Malling H-J.New ideas in allergen-specific immunotherapy.Am J Rhinol1990;4:155–8.9Malling H-J,Weeke B.EAACI Position Paper:Immuno-therapy.Allergy1993;48:9–35.10Varney VA,Gaga M,Frew AJ et efulness of immuno-therapy in patients with severe summer hay fever uncontrolled by antiallergic drugs.Br Med J1991;302:265–9.11Nelson HS,Oppenheimer J,Vatsia GA,Bucheimer A.A double blind placebo controlled evaluation of sublingual immunotherapy with standardized cat extract.J Allergy Clin Immunol1993;92:229–36.12Novembre E,Marano E,Bernardini R et al.Studio controllato sull’immunoterapia sublinguale nel tratta-mento dell’asma allergico nel bambino.Riv It Ped1991,17:75–8.13Casanovas M,Guerra F,Moreno C et al.Double blind placebo controlled clinical trial of preseasonal treatment with allergenic extracts of olea europaea pollen administered sublingually.J Invest Allergol Clin Immunol1994;4:305–14.14Tari MG,Mancino M,Monti G.Efficacy of sublingual immu-notherapy in patients with rhinitis and asthma due to house dust mite.A double blind study.Allergol et Immunopathol1990;18;277–84.15Van Niekerk CH,De Wet JI.Efficacy of grass-maize pollen oral immunotherapy in patients with seasonal hay fever:a double blind study.Clin Allergy1987;17:507–13.16Sabbah A,Hassoun S,Le Sellin J,Andre C,Sicard H.A double blind placebo controlled trial by the sublingual route of immunotherapy with a standardized grass pollen extract.Allergy1994;49:309–13.1230H.-J.Malling#1996Blackwell Science Ltd,Clinical and Experimental Allergy,26,1228–123117Troise C,Voltolini S,Canessa A,Pecora S,Negrini AC.Sublingual immunotherapy in parietaria pollen induced rhini-tis:a double blind study.J Invest Allergol Clin Immunol1995;5:25–30.18Feliziani V,Lattuada G,Parmiani S,Dall’Aglio PP.Safety and efficacy of sublingual rush immunotherapy with grass allergen extracts.A double blind study.Allergol et Immunopathol 1995;23:224–30.D R H.-J.M ALLINGAllergy Unit7551Rigshospitalet20TagensvejDK-2200Copenhagen NDenmark Sublingual immunotherapy1231#1996Blackwell Science Ltd,Clinical and Experimental Allergy,26,1228–1231。

临床检验相关英文杂志1.Clinical Chemistry临床化学杂志, 2006年影响因子5.454. 2005年:7.717. 临床化学（检验）专业的王牌杂志.网址:/,该杂志由美国临床化学协会(American Association for Clinical Chemistry)主办，编委和主编都是检验界最顶级的专家，现任编委为Nader Rifai，是心血管疾病标志物的专家。

来自中国的编委只有一个，是香港中文大学的卢煜明教授，循环核酸检测领域的权威。

该杂志为月刊，主要刊登检验医学领域最激动人心的成果，包括：实验室指标的评价（主要是心血管，内分泌领域大样本的，前瞻性的研究），新的检测方法评价，临床病例学习（都有顶级专家点评），专家评论等。

我国平均每年在该杂志上发10-15篇论文，多数是中科院以及各医科大学从事分子生物学，生物化学的单位发的，纯由医院检验科发的文章较少.以下是杂志的英文介绍（摘自杂志主页）：Clinical Chemistry is the leading forum for peer-reviewed, original research on innovative practices in today s clinical laboratory. In addition to being the most cited journal in the field (over 18,000 citations in 2005), Clin Chem has the highest Impact Factor (7.717 in 2005) among journals of clinical chemistry, clinical (or anatomic) pathology, analytical chemistry, and the subspecialties, such as transfusion medicine, clinical microbiology. The journal issued monthly, publishes contributions, either experimental or theoretical, that concern basic materials or principles, analytical and molecular diagnostic techniques, instrumentation, data processing, statistical analyses of data, clinical investigations in which chemistry has played a major role, or laboratory animal studies of chemically oriented problems of human disease.2.Clinical Chemistry and Laboratory Medicine临床化学和实验室医学杂志http://www.degruyter.de/journals/cclm/2006年影响因子1.725. 是FESCC（欧洲临床化学和实验室医学学会论坛）和IFCC （国际临床化学和实验室医学学会论坛联合会）的官方出版物。

Chapter1Antibody–Drug Conjugate(ADC)Clinical Pipeline:A Review Ingrid Sassoon and Ve´ronique BlancAbstractBiological therapies play an increasing role in cancer treatment,although the number of naked antibodies showing clinical efficacy as single agent remains limited.One way to enhance therapeutic potential of antibodies is to conjugate them to small molecule drugs.This combination is expected to bring together the benefits of highly potent drugs on the one hand and selective binders of specific tumor antigens on the other hand.However,designing an ADC is more complex than a simple meccano game,requiring thoughtful combination of antibody,linker,and drugs in the context of a target and a defined cancer indication.Lessons learned from thefirst-generation antibody–drug conjugate(ADC)and improvement of the technology guided the design of improved compounds which are now in clinical trials.Brentuximab vedotin(Adcetris®),an anti-CD30antibody conjugated to a potent microtubule inhibitor for the treat-ment of Hodgkin’s lymphoma and anaplastic large cell lymphomas,is the only marketed ADC today.A total of27ADC are currently undergoing clinical trials in both hematological malignancies and solid tumor indications.Among them,T-DM1(trastuzumab emtansine),an ADC comprised of trastuzumab conjugated to DM1,via a non-cleavable linker,is showing very promising results in phase III for the treatment of HER2-positive refractory/relapsed metastatic breast cancer.Other compounds,such as CMC-544,SAR3419,CDX-011,PSMA-ADC,BT-062,and IMGN901currently in clinical trials,target-ing varied antigens and bearing different linker and drugs,contribute to the learning curve of ADC,as do the discontinued ADC.Current challenges include improvement of the therapeutic index,linked to a careful selection of the targets,a better understanding of ADC mechanism of action,the management and understanding of ADC off-target toxicities,as well as the selection of appropriate clinical settings(patient selection,dosing regimen)where these molecules can bring highest clinical benefit.Key words Antibody–drug conjugate,Cancer,Cytotoxic,Linker,Antibody,Maytansine,Auristatin, Calicheamicin,T-DM1,SGN-35,CMC-5441IntroductionDecades of intensive research in oncology have been devoted tofind drugs able tofight cancer and improve patient’s life.Nowa-days,cancer biologics(antibodies,peptides,and proteins)play anincreasing role in the arsenal of therapeutic molecules,usually incombination with radiotherapy or chemotherapy.Despite clear Laurent Ducry(ed.),Antibody-Drug Conjugates,Methods in Molecular Biology,vol.1045,DOI10.1007/978-1-62703-541-5_1,#Springer Science+Business Media,LLC201312Ingrid Sassoon and Ve´ronique Blancadvantages of antibodies compared to small molecules in termsof(a)exquisite selectivity towards antigen-positive cells,leadingto decreased off-target toxicity and(b)long half-life,only13thera-peutic antibodies are marketed today for the treatment of cancer[1],highlighting the difficulty to identify targets whose modulationwill impact tumor growth as well as the difficulty to identifyantibodies with clinical efficacy as single agent.Arming antibodiesor antibody fragments with toxins,cytotoxic drugs,and radionu-clides can be viewed as a means of enhancing tumor-cellkilling while sparing normal cells.Several of such armed moleculesare marketed,namely,denileukin diftitox(Ontak®),an engineeredprotein combining interleukin-2(which binds to IL2R)andDiphteria toxin,for the treatment of persistent or recurrent cuta-neous T cell lymphoma,ibritumomab tiuxetan(Zevalin®),and131I-tositumomab(Bexxar®),two murine anti-CD20antibodiesconjugated to90Y and131I,respectively,for the treatment ofrelapsed/refractory follicular lymphoma,as well as the antibody–drug conjugate(ADC)brentuximab vedotin(Adcetris®),an anti-CD30antibody conjugated to a potent microtubule inhibitorfor the treatment of Hodgkin’s lymphoma and anaplastic largecell lymphomas.The concept of arming antibodies is not recent,as the use ofADC in animal models was already described in the literature in the1970s,and clinical trials with murine IgG-based ADC were con-ducted in the1980s,although with limited success.This is only in2000that thefirst ADC,gemtuzumab ozogamicin(Mylotarg®),ananti-CD33antibody conjugated to calicheamicin(a very potentDNA binding drug),was approved in the USA for the treatmentof acute myelocytic leukemia(AML),based on clear evidence ofblast decrease in patient bone marrows[2,3].In2010,the productwas withdrawn from the market by the developer,Pfizer,followinginterim results from post-approval study(SWOG S0106),becauseof serious concerns about product’s safety and failure to demon-strate clinical benefit[4].This review will focus on ADC which are undergoing clinicaltrials(cf.Table1).Lessons learned fromfirst-generation ADC andimprovement of the technology,both described in thefirst section,guided the design of improved compounds which are currently atdifferent stages of clinical development.Adcetris®and the mostadvanced ADC in clinical trials will be described in a second section.The third section covers explored areas of improvement based on athorough understanding of key parameters for ADC safety andefficacy retrieved from preclinical and clinical trials.The growingnumber of ADC in the clinic reflects the interest and confidence ofclinicians and pharmaceutical companies that this approach canbring high benefit to cancer patients.T a b l e 1A D C i n c l i n i c a l t r i a l s a n d l a u n c h e d(c o n t i n u e d )Antibody–Drug Conjugate (ADC)Clinical Pipeline:A Review34Ingrid Sassoon and Ve´ronique BlancC u r r e n t h i g h e s t p h a s e f o r c a n c e r /fir s t d a t e /fir s t i n d i c a t i o n n d n o t d i s c l o s e dAntibody–Drug Conjugate (ADC)Clinical Pipeline:A Review52ADC Building Blocks2.1Definition of an ADC An ADC can be defined as a prodrug.The antibody connected to the cytotoxic warhead(drug)via a linker serves as targeted delivery system to the tumor expressing the antigen/target recognized by the antibody.Ideally,in blood,after systemic administration,this prodrug is nontoxic.Upon binding of the antibody to the targeted tumor antigen and internalization of the complex into the cancer cell,the drug is then released in its active form and in sufficient quantity to kill the cell.Designing an ideal ADC is more complex than a simple meccano game.On top of the careful choice of a target/antigen expressed in specific tumor indication,it requiresfinding the best combination between the antibody,the linker,and the drug,which, besides its own characteristics and constraints,are linked and impact each other.2.2Target/Antigen for ADC The target/antigen is the starting point to build an ADC.Itfirst determines which tumor indication will be targeted by the ADC and potentially impacts the choice of the conjugated drug. In addition,the target will also drive the criteria which will be defined for the selection of the targeted patient population within the tumor indication.Many targets have been evaluated for an ADC approach across the years(for a review,see ref.5),showing that a high variety of targets,either single or multiple transmembrane domains proteins or glycosylphosphatidylinositol(GPI)-anchored,can lead to ADC internalization and subsequent tumor growth delay and regression in preclinical mouse models.The basis for the selection of the antigen is a high expression level in tumor tissues and a restricted normal tissue distribution,in order to limit on-target toxicity of the future ADC.However, tumor-specific antigens with no expression in normal tissues are rare,and most of the time,the antigen is expressed at the surface of epithelial cells in a subset of normal tissues/organs.The type of organ expressing the antigen(vital organs vs.reproductive organs, for example),the cellular subtype and cell-cycle status(dividing cells vs.differentiated quiescent cells),and the differential of expression between normal antigen-positive cells and tumor cells are to be considered for selection of the target.It is important to notice that expression in normal organs may not always mean subsequent toxicity in clinical trials.Several ADC with normal tissue cross-reactivity have been well tolerated in patients,causing minimal or manageable and reversible toxicities, namely,cantuzumab mertansine/IMGN242(targeting CanAg antigen,a glycotope on Mucin-like protein[6,7]),BT-062(target-ing CD138;see below),or CDX-011(targeting gpNMB;6Ingrid Sassoon and Ve´ronique Blancsee below).Inversely it has clearly been demonstrated in the case of bivatuzumab mertansine (targeting CD44v6),whose trial was pre-maturely stopped in phase I (cf.Table 2),that the expression of the CD44v6target in skin keratinocytes [8]led to severe skin toxicity,including a fatal case of toxic epidermal necrolysis [9–11].While expression of the target should remain limited and at low level in normal tissues,on the contrary,the level of expression (antigen density)at the surface of cancer cells should be high and combined to the ability of the antigen/antibody complex to inter-nalize and be processed in the right subcellular compartments,in order to release enough quantity of the active drug in the cytosol.The use of tumor models mimicking the target expression pattern and level found in patient biopsies is a very critical element to translate preclinical data into clinical efficacy.AVE9633,an immu-noconjugate targeting CD33antigen,did not show clinical efficacy in phase I [12]in part because of too limited antigen expression on the malignant cell population,suggesting an insufficient delivery ofTable 2Discontinued ADCProduct name Target nameDrug/linkerReasons for discontinuationYear ReferencesBAY79-4620CAIX MMAE/vc Not disclosed2011Press releaseIMGN388Integrin αv β3DM4/SPDB Change in business strategy 2011Press release MEDI547EphA2MMAF/mc Safety issues:bleeding and coagulation events 2012[122]Mylotarg CD33Calicheamicin/hydrazone Failure to demonstrate clinical benefit 2010[4]BIIB015Crypto1DM4/SPDB Not disclosed 2010IMGN242CanAg DM4/SPDB Not disclosed 2009Press release AVE9633CD33DM4/SPDB Lack of clinical efficacy 2008[12]MLN2704PSMADM1/SPPNot disclosed 2006[94,123],Press release CMD-193Le Ycarbohydrate Calicheamicin/hydrazone Not disclosed2006ClinicalTrials.gov Bivatuzumab mertansine CD44v6DM1/SPPSafety issues:fatal case of toxic epidermal necrolysis2006[9,11]SGN-15Le Y carbohydrate Doxorubicin/hydrazone Change in business strategy 2005Press release CMB-401MUC1Calicheamicin/hydrazoneLack of clinical efficacy1999[124,125]Antibody–Drug Conjugate (ADC)Clinical Pipeline:A Review 7molecules in the cytoplasm to achieve cell death.In contrast, preclinical models showed good response to AVE9633[13]but displayed a much higher CD33antigen level than the one measured in patient biopsies(unpublished internal data,sanofi,2009).2.3Drugs and Linkers Many conventional therapeutic agents have been conjugated to antibodies,but it soon became clear that they were not potent enough,when conjugated,to achieve antitumor activity in the clinic[14–16].Efforts have then been turned towards natural small cytotoxic molecules with higher potency but which have been found too toxic as free drug in clinical trials.Currently,only few highly potent natural cytotoxics,derivatives,or synthetic ana-logues have been conjugated to antibodies and progressed to the clinic.They fall into the following two classes:microtubule desta-bilizing agents(auristatin derivatives,MMAE and MMAF and maytansinoid derivatives,DM1and DM4)and DNA minor groove binders(calicheamicin and duocarmycin derivatives).Both classes are extremely potent towards proliferating tumor cell lines[16]. IC50of proliferation/viability of tumor cell lines are in the range of 10À10–10À12M for DM1/DM4maytansinoid derivatives[17,18], 10À7–10À10M for MMAF/MMAE auristatin derivatives[19], around10À10M for N-acetyl-γcalicheamicin DMH[20],and 10À11–10À12M for DC1and CC-1065duocarmycin precursors [14,21].Importantly,the engineered linker connecting the cytotoxic molecule to the antibody has been deeply studied as it is considered to be an important parameter for preclinical,clinical efficacy and safety of ADC:linkers must be stable enough in circulation since release of the cytotoxic payload may be associated with undesired and untargeted toxicities,but they must also be able to efficiently release cytotoxics in their active form in the cytosol of the target cell following internalization and trafficking in specific subcellular com-partments[16,22,23].Indeed,upon binding of the ADC to its target,and subsequent internalization of the antigen/ADC com-plex by receptor-mediated endocytosis,the ADC is trafficked in acidifying endosomal and then in lysosomal vesicles,a compart-ment rich in proteolytic enzymes.Due to the chemical environment or to the metabolic properties of these intracellular compartments, the ADC is activated/metabolized.This metabolization depends on the type of linker connected to the drug:–The acid labile hydrazone linkers are relatively stable at neutral pH(pH7.3–7.5,pH of the bloodstream)but undergo hydroly-sis once the ADC is internalized into acidic endosomes(pH 5–6.5)and lysosomes(pH4.5–5).They have been conjugated to doxorubicin,calicheamicin,and auristatin.Their relative stability depends on the antibody part attached,but they have8Ingrid Sassoon and Ve´ronique Blancbeen associated with high nonspecific release of the drug in circulation in preclinical studies[24].–The disulfide-based linkers have been combined with DM1and DM4maytansinoids.The corresponding ADC is activated by lysosomal degradation of the antibody part,resulting in meta-bolites consisting of intact maytansinoid drug and linker attached to lysines[23,25].Linkers are subsequently reduced with more or less efficiency,depending on the level of steric hindrance at carbon atoms adjacent to the disulfide linkage, optimized linkers being the best compromise between high ADC plasma stability and efficient metabolization/release of the metabolites in tumor cells[26].–The peptide-based linkers,already used for a number of years with doxorubicin,mitomycin C,camptothecin,and talysomycin[16],have been designed for the auristatin and the duocarmycinderivatives.The type of linker which has been progressed to clinical stage is composed of a valine–citrulline dipeptide selec-tively hydrolized by cathepsin B and plasmin enzymes,a self immolative spacer that spatially separates the drug from the site of enzymatic cleavage,and the auristatin E microtubule disruptive agent or duocarmycin prodrug derivative.In the case of an auristatin E conjugate,the membrane-permeable monomethyl auristatin E accounts for the only detectable metabolite found in antigen-positive cells[27].–Contrary to the above linker types,which are considered as “cleavable,”thioether bond containing linkers are considered as“non-cleavable,”and the corresponding ADC have been clinically tested with DM1and MMAF cytotoxics.In this case, the degradation of the mAb component into the lysosomes releases the drug still attached to the linker via a Lys or Cys residue of the antibody.These charged entities are not able to cross membranes with high efficiency,by contrast to metabolites of maytansine and auristatin ADC conjugated to“cleavable”linkers.In this case,the diffusion of metabolites induces killing of surrounding cells,a property named“bystander effect”[27–29].2.4Antibody Selection All ADC currently in oncology clinical trials are canonical(i.e.,full length)IgG molecules,mostly of the IgG1isotype.They are either chimeric,humanized,or fully human antibodies(cf.Table1).The generation of an immune response to these ADC has remained very limited,highlighting the benefit of antibody engineering technol-ogies over the last decades,as well as the fact that small molecule cytotoxics,contrary to natural toxins,are not immunogenic.Attention has also been focused on drug conjugation technol-ogies on the selected antibodies.On top of the fact that drug Antibody–Drug Conjugate(ADC)Clinical Pipeline:A Review9conjugation should not disturb antigen/antibody interaction,thelocalization,the number,and the nature of the attachment betweenlinker and antibody have been shown to influence pharmacokinet-ics,tumor exposure,and ADC plasma stability[30,31].So far,thetwo conjugation technologies which progressed to clinical trials arebased on the following two principles:either conjugation throughLysine side chain amines(with drugs such as DM1,DM4,orcalicheamicin)or conjugation through cysteine sulfhydryl groupsactivated by reducing interchain disulfide bonds(with drugs such asMMAE,MMAF,or duocarmycin)of the antibody.Both processesgive more or less heterogeneous mixtures of ADC with variabledrug load per antibody and variable sites of conjugation to theprotein.This heterogeneous mixture is defined by an averagedrug–antibody ratio(DAR)and is challenging from a developmentpoint of view,although robust analytical technologies and processesare available to ensure constant quality control of thefinalproduct[32].3Current Clinical Results of Antibody–Drug ConjugatesA total of27ADC are currently in clinical trials,20in phase I,5inphase II,2in phase III,and1launched ADC(cf.Table1).A totalof12ADC have been stopped and are listed in Table2.3.1Brentuximab Vedotin(Adcetris®) Clinical Overview CD30,a type II transmembrane protein belonging to the TNF (tumor necrosis factor)superfamily,is abundantly and selectively expressed on the surface of Hodgkin’s lymphoma(HL),Reed–Sternberg(RS)cells,anaplastic large cell lymphomas(ALCL),and other lymphoid malignancies as well as on several nonlymphoid malignancies[33].RS cells and ALCL cells express high levels of CD30,but the downstream signalling of CD30may differ between both diseases[34,35].In non-pathological conditions,CD30 expression is highly regulated and restricted to activated B and T lymphocytes and NK cells,low expression being also noticed in monocytes and eosinophils(for review,see refs.34,36),making it a good candidate target for an ADC strategy.HL is considered as one of the most curable cancers,with a 5-year survival rate of above85%although up to20%of patients are refractory and advanced-stage patients often relapse[37]. In frontline systemic ALCL treatment,disease recurs in40–65% of patients[38].Clinical trials have been reported for unconjugated anti-CD30 antibodies[39].Acceptable safety profile but modest antitumor clinical activity precluded further development as naked but supported exploration and development of a conjugated version: SGN-35.SGN-35(Adcetris®,brentuximab vedotin)is an ADC comprised of a chimeric anti-CD30antibody(cAC10)conjugated10Ingrid Sassoon and Ve´ronique Blancthrough interchain disulfide bonds to monomethyl auristatin E(MMAE)via a valine–citrulline dipeptide cleavable linker,with an average DAR of4[40].Based on preclinical data showing good efficacy of SGN-35at low doses in lymphoma models[40],a phase I study was conducted in2006.Forty-five patients(42HL,3ALCL)were enrolled,in a dose escalation study ranging from0.2to3.6mg/kg with intrave-nous(IV)administration once every3weeks(q3w)[41].The maximum tolerated dose(MTD)was found to be1.8mg/kg, and drug-related dose-limiting toxicities(DLT)were febrile neu-tropenia and hyperglycemia.At the MTD,objective clinical responses were observed,with an objective response rate(ORR) of38%,including4complete responses(CR)and2partial responses(PR)out of12patients.In terms of pharmacokinetics (PK),terminal half-life of the ADC and MMAE,at1.8mg/kg,was estimated to be4–6and3–4days,respectively[41].In a second phase I study,enrolling44patients,a more frequent regimen was investigated,at doses ranging from0.4to1.4mg/kg administered weekly for3out of4weeks,for a total of four cycles.The MTD was 1.2mg/kg and the ORR was59%,with34%CR.Most common grade3adverse events(AE)were peripheral sensory neuropathy (14%),anemia(9%),neutropenia(7%),peripheral motor neurop-athy(7%),and hyperglycemia,diarrhea,and vomiting(5%each). Overall,32patients(73%)experienced one or more events of peripheral pared to the q3w schedule,there was a marked increase in neuropathy which led to the adoption of the q3w schedule for further clinical studies[42].In a phase II study,102heavily pretreated relapsed or refractory HL patients were treated at the dose of1.8mg/kg in a q3w schedule[43].The ORR was75%including34%CR and40% PR.The more severe AE were grade3neutropenia(14%),periph-eral sensory neuropathy(5%),fatigue and hyperglycemia(3% each),grade4hematological toxicities(neutropenia4%;thrombo-cytopenia1%),and pulmonary embolism and abdominal pain(1% each).In a second phase II trial,58patients with relapsed systemic ALCL were treated with1.8mg/kg of with a q3w schedule[38]. The ORR was86%with53%achieving CR.Grade3–4AE were similar to the previous studies.Based on these outstanding data,SGN-35has been granted accelerated approval by the FDA in August2011for the treatment of HL that had relapsed after autologous stem cell transplant (ASCT)and for the management of relapsed ALCL,making it thefirst approved drug over30years in HL.In July2012,a positive opinion was issued in the EU,recommending conditional market-ing authorization for treatment of adults with relapsed or refractory CD30-positive HL following ASCT or following at least two prior therapies when ASCT or multi-agent chemotherapy is not a treat-ment option as well as for the treatment of adults with relapsedor refractory systemic ALCL.SGN-35is currently evaluated in a phase III randomized,double-blind,placebo-controlled study (AETHERA)in HL patients following autologous stem cell trans-plant[35].Interim results show that75%of patients responded to the drug,including34and40%achieving CR and PR,respectively [44].Future results of the AETHERA trial expected to be com-pleted in June2013will form the basis for full FDA approval.Other trials are ongoing,including another phase III trial evaluating SGN-35versus methotrexate or bexarotene in patients with CD30-positive cutaneous T cell lymphomas[44].3.2Trastuzumab-DM1(T-DM1)Clinical Overview ErbB2/neu/HER2is a member of the ErbB receptor tyrosine kinase family which is involved in cell growth,survival,and differ-entiation[45].Breast cancer accounts for28%of all new cases of cancer in women,and15–25%of these new cases contain gene amplification or overexpression of HER2[46].The humanized anti-HER2monoclonal antibody trastuzumab(Herceptin®;Gen-entech),and the dual epidermal growth factor EGFR/HER2tyro-sine kinase inhibitor lapatinib(Tykerb®,GSK),in combination with chemotherapy,prolongs survival of HER2-positive breast can-cer patients in metastatic and adjuvant settings.However,a signifi-cant portion of these patients relapse andfinally die from their cancer,highlighting the need for new therapeutic approaches [47,48].T-DM1(trastuzumab emtansine)is an ADC comprised of tras-tuzumab conjugated through lysines to DM1,via a non-cleavable thioether linker(N-succinimidyl4-(N-maleimidomethyl)cyclohex-ane-1-carboxylate,SMCC),with an average DAR of3.5[49].Preclinical studies of T-DM1suggested that the ADC retained all activities of unconjugated trastuzumab,inhibition of PI3K/ AKT signalling,inhibition of HER2shedding,and Fcγreceptor engagement triggering ADCC[50].Moreover,T-DM1showed a strong growth inhibitory effect on trastuzumab-resistant breast cancer cell lines in vitro,as well as a significant inhibition of tumor growth when administered in trastuzumab and lapatinib resistant tumor-bearing mice[49,51].Four phase I/II studies evaluated T-DM1as single agent for the treatment of HER2-positive refractory/relapsed metastatic breast cancer.In2006,24patients were enrolled in a phase I dose escala-tion study,with doses ranging from0.3to4.8mg/kg,in a q3w schedule[52].T-DM1MTD was identified at3.6mg/kg without cardiotoxicity or neuropathy.Transient grade4thrombocytopenia was the most common adverse event and was defined as the DLT [52].Encouraging antitumor activity was observed:out of15 patients enrolled in the3.6mg/kg group,four had a confirmed objective partial response.One confirmed PR was also observed in the2.4mg/kg group[52].A phase I weekly dosing[53]reported MTD at2.4mg/kg,with thrombocytopenia being also the DLTand showing the same range of activity.Different phase II studies evaluated T-DM1at3.6mg/kg,q3w(for review,see refs.54,56). In one study[57]a median of seven doses was administered to112 patients with HER2-positive metastatic breast cancer previously treated with chemotherapy and progressed under trastuzumab ther-apy.The ORR evaluated by independent review was25.9%,all PR. Interestingly,in the group of tumors confirmed HER2-positive in a retrospective central testing by immunohistochemistry(IHC)or fluorescence in situ hybridization(FISH),the ORR was33.8% versus4.8%for the group of tumors with normal HER2expression. The most common grade3or4AE were hypokalemia(8.9%), thrombocytopenia(8.0%),and fatigue(4.5%).PK parameters showed a terminal half-life of T-DM1of around4days,which was found to be lower than the total trastuzumab half-life.No accumu-lation of T-DM1was reported[57].In a second study,T-DM1was administered in110patients with metastatic breast cancer previ-ously treated with an anthracycline,a taxane,and capecitabine,as well as lapatinib and trastuzumab[58].The ORR by independent review was34.5%without CR and again rose to41.3%for patients with tumors centrally confirmed for HER2-positivity(FISH and IHC)compared to20%in the patient group displaying HER2-normal expression levels.The most common grade3and4AE were thrombocytopenia(9.1%),fatigue(4.5%),and cellulitis(3.6%). In the different studies,thrombocytopenia was one of the most reported grade3or4abnormalities,but the decrease in platelets was generally reversible and not associated with serious hemorrhage [56–58].Increased serum concentrations of hepatic enzymes was observed[56].T-DM1exposure did not correlate with clinical responses,grade3thrombocytopenia or grade3increase in hepatic enzymes serum concentrations[59].The comparison of pharmaco-kinetics data from phase I and phase II studies,as single agent, demonstrated a positive correlation between DM1and T-DM1 exposure with neither accumulation of T-DM1nor DM1[59, 60].At the MTD,T-DM1showed a median terminal half-life of 4.5days which is shorter than the one from total trastuzumab (around9days)[59,60].The PK profile of T-DM1was not affected by circulating levels of HER2or residual trastuzumab[59,60].On a total of286patients,4.5%developed an antibody response to T-DM1but no impact on PK parameters,safety or efficacy profiles were observed[59].Interestingly a randomized phase II study was conducted to compare T-DM1versus trastuzumab plus docetaxel[55]in the first-line treatment of HER-2-positive locally advanced or meta-static breast cancer.A total of137patients,with no prior chemo-therapy for metastatic disease,were randomized to T-DM1 (3.6mg/kg,q3w)or trastuzumab(8mg/kgfirst cycle,then 6mg/kg)plus docetaxel(75or100mg/m2).Assessment by investigators showed equivalent ORR of47.8%with T-DM1and41.4%with docetaxel plus trastuzumab[61]but with improved therapeutic ratio in the case of T-DM1.Primary efficacy and update on safety results were presented at ESMO2011[62]with a signifi-cant improvement of progression-free survival(PFS)in the T-DM1 population(14.2months vs.9.2months)and a confirmed favor-able safety profile with grade3AE reported less frequently in the T-DM1arm(46.4%vs.89.4%).The most frequent AE were also different between the two arms,with increased level of liver enzymes,fatigue and thrombocytopenia in the T-DM1arm versus alopecia,neutropenia,fatigue,and diarrhea in the trastuzumab/ docetaxel arm.In addition,three phase III trials(EMILIA,MARIANNE and TH3RESA)are ongoing[55].EMILIA is a randomized trial designed to evaluate the safety and efficacy of T-DM1in compari-son to lapatinib plus capecitabine in patients with HER-2positive, unresectable,locally advanced breast cancer or metastatic breast cancer,following prior trastuzumab and taxane containing che-motherapies.Recent publication of thefirst and second interim analysis of the991patients enrolled indicates that T-DM1signifi-cantly improves PFS(9.6months vs.6.4months)and overall survival(OS)(30.9months vs.25.1months)as compared to lapatinib plus capecitabine treatment[63].In addition,as previ-ously shown in phase II,the safety profile of T-DM1was different and more favorable than lapatinib plus capecitabine,as shown by the reduced incidence of grade3and4AE(40.8%vs.57.0%). Thrombocytopenia(12.9%)and elevated AST(4.3%)were the most commonly reported AE for T-DM1,while diarrhea(20.7%), palmar–plantar erythrodysesthesia(16.4%),vomiting(4.5%),and neutropenia(4.3%)were the ones reported for lapatinib plus capecitabine[63].On the basis of this study,a Biologics License Application(BLA)wasfiled in August2012.MARIANNE is a randomized trial of T-DM1with or without pertuzumab compared with trastuzumab plus taxane forfirst-line treatment of HER2-positive,progressive,or recurrent locally advanced or metastatic breast cancer.TH3RESA is a randomized trial to evaluate the efficacy of T-DM1compared with treatment of physician’s choice in patients with HER2-positive metastatic breast cancer who have received at least two prior regimens of HER2-directed therapy.3.3CMC-544 (Inotuzumab Ozogamicin)Clinical Overview CD22is a glycoprotein belonging to the sialic-acid-binding immunoglobulin-like lectins(siglecs)expressed at the surface of normal immature and mature B cells but neither on hematopoietic stem cells nor on memory B cells.Its function is still unclear,but it is thought to be involved in cellular adhesion,B-cell homing, and B-cell activation[64].CD22has been shown to be rapidly internalized upon ligand binding,an attractive property supporting CD22as target for ADC[65].CD22is expressed in more than90%of diffuse large B-cell non-Hodgkin lymphomas。