The Role and Application of Biomarkers and Surrogate Endpoints for New Drug Development : Focused on Diabetes Mellitus and Osteoporosis

당뇨병 및 골다공증 치료제의 효율적인 신약개발을 위한 생체표지자 및 대리 결과 변수의 역할 및 활용

성수현·윤휘열·백인환·강원구*·장정윤**·서경원**·권광일^# 충남대학교 약학대학 임상약학 연구실, *대구 가톨릭대학교 약학대학 임상약학 연구실,

**식품의약품안전청 기관계용의약품팀

(Received April 2, 2008; Revised August 23, 2008)

The Role and Application of Biomarkers and Surrogate Endpoints for New Drug Development : Focused on Diabetes Mellitus and Osteoporosis

Soo-Hyeon Seong, Hwi-Yeol Yun, In-Hwan Baek, Wonku Kang*, Jung Yun Chang**, Kyung Won Seo** and Kwang-Il Kwon^#

College of Pharmacy, Chungnam National University, Daejeon 305-764, Korea

*College of Pharmacy, Catholic University of Daegu, Kyungbuk 712-702, Korea

**Gastrointestinal, Urinary and Metabolic Drug Team, Korea Food and Drug Administration, Seoul 122-704, Korea

Abstract

— Recently, the FDA (Food and Drug Administration) of the United States and many advanced countries remark biomarkers and surrogate endpoints as a critical path tool on model based drug development. Economic, technical and social profit on model based drug development like a reduction of the length of research and development have been achieved.

Therefore we summarize previous studies about biomarkers and surrogate endpoints and suggest a development direction of therapeutic agents. In diabetes mellitus (DM) and osteoporosis, there are remarkable increases in number of patients and most of patients take medicine during their whole lifetime. For this reason, many patients with DM and osteoporosis have a tolerance on their medicine. We expect that research and development on biomarkers and surrogate endpoints will con- tribute to new drug development on DM and osteoporosis. Biomarkers for DM are blood levels of glucose, insulin, HbA

1c

, CRP, alpha-glucosidase, adiponectin and DPP-4. Among these, validated surrogate endpoints for DM are blood levels of glu- cose, insulin and HbA

1c

. Biomarkers for osteoporosis are BMD, BMC, trabecular volume, ICTP, DPD, osteocalcin, the activ- ity of osteoclast and production of osteoblast. The validated surrogate endpoints for osteoporosis are BMD only. This review summarizes all suggested biomarkers and surrogate endpoints in DM and osteoporosis. The biomarkers are classified by drugs, and the method of validation for surrogate endpoints is suggested. This information would contribute to suggest a direction of DM and osteoporosis therapeutic agent development.

Keywords □

biomarker, surrogate endpoint, diabetes mellitus, osteoporosis, critical path

오늘날신약이개발되어서시장에나오기까지걸리는기간 이평균

15

년이소요되고연구

,

개발과정에서소요되는비용이

10

^{억달러에달하며비용의대부분이제약시장에채나오기도}

전에소실된다

.

^{많은비용으로전임상실험을진행하지만}

FDA (Food and Drug Administration)

의

IND(investigational new

drug)

^{승인에통과되는약물은}

10%

^{정도에불과하다}

.

^1)매년신

약개발을위한투자비용은증가하는반면신약의허가는감소 또는정체하는추세를보이고있다

.

임상시험진행을위해연구

목적으로허가를받은

IND

^의경우

50%

^{이상이임상}

3

^상에서시

험실패하여드롭아웃

(drop out)

^{되는실정이고이러한현상은}

신약개발사업이저효율

,

고비용산업으로되는결정적인역할 을하고있다

.

^{2)이러한문제점을해결하기위한방안으로연구}

,

개발

(research and development)

^{과정의새로운접근이요구되고}

있다

.

그러한노력의일환으로최근

FDA

에서는연구

,

개발과정

에

critical path

^{란개념을도입하여근거에기반한보다과학적}

이고효율적이고생산적인방법개발에주력하고있다

.

¹⁾

FDA

에

#본논문에관한문의는저자에게로

(

^전화

) 042-821-5937 (

^팩스

) 042-823-6781

(E-mail) [email protected]

서는보다구체적으로신약개발과정에효율성과생산성을동 시에증가시킬수있을만한

76

^{개의후보프로젝트를제시했다}

.

그중중요한비중을 차지하는프로젝트가생체표지자 개발

(biomarker development)

^이다

.

^{1)본종설에서다루고자하는생}

체표지자

(biomarker)

^{의개발은세계적인추세이고특히발리데}

이션

(validation)

이용이한생체표지자의개발은효과적인신약

개발에중추적인역할을할수있다

.

생체표지자는일반적인생물학적

,

^{병리학적과정또는치료시}

술에대한약리학적반응의지표로서객관적으로측정가능하고

평가될수있는특징이며대리결과변수

(surrogate endpoint)

^나

임상결과변수

(clinical endpoint)

와깊은연관성을가진다

(Fig. 1).

³⁾

대리결과변수는임상결과변수로대체할수있을만큼연관 성이큰생체표지자이고전염병학적

,

^치료학적

,

^병태학적

,

^또는

다른여러과학적증거에기반을둔임상적이로움

,

해로움을예 측할수있을만한생체표지자을의미한다

.

임상결과변수는환 자가어떻게느끼고반응하고살아있는가를반영해주는특징 또는변수를의미한다

.

^{3)대리결과변수가신약개발에응용하는}

데가장유용한생체표지자이다

.

그러나현재까지밝혀진생체 표지자중대리결과변수로인정받고있는생체표지자는극소 수이며

,

앞으로연구가계속적으로이루어져대리결과변수로 인정받을수있는생체표지자가많이개발되어야한다

.

당뇨병과골다공증은대중적인질병이고동시에한번진단을 받게되면평생약을필요로하는만성질환이다

.

그런만큼내성

(tolerance)

이생기는경우가많다

.

이로인해같은기전의약은

내성을가지게되어용량을늘여줘야하고결국은효능을얻지 못하는경우가빈번하다

.

따라서당뇨병과골다공증은현재있 는기전과는다른기전의신약의개발이필수적이다

.

^본종설에

서는이러한점에착안하여당뇨병과골다공증의생체표지자와 대리결과변수를조사하였다

.

본종설에서는위에서언급한생체표지자

,

^{대리결과변수의}

개념을대사성질환인당뇨병과골다공증에적용시켜현재까지 발견된생체표지자

,

대리결과변수를정리하였다

.

생체표지자와 대리결과변수를당뇨병과골다공증에직접적용시켜봄으로서

현재까지의연구

,

^{개발상황을평가하고앞으로의연구방향을}

설정하는데도움이되고자하였으며나아가서는당뇨병과골다 공증외질병에도생체표지자와대리결과변수의연구

,

개발이 진행되어야함을인지시키고자한다

.

생체표지자 (biomarker) ^및

대리 결과 변수 (surrogate endpoint)

생체표지자

(biomarker)

^{및 대리 결과 변수}

(surrogate end- point)

^의선택

Biomarkers Definition working group(BDWG)

에서는생체표

지자와대리결과변수의총체적인영향력평가

(global intervention

assessment)

^{를위한개념적인모델을제시함으로써생체표지자}

및대리결과변수를통한임상시험시고려해야할사항에대 한정보를주고있다

(Fig. 2).

⁴⁾

Fig. 2

에의하면임상결과변수 와역학적

,

^{병태생리학적}

,

^{치료학적으로연관을가진생체표지자}

는임상시험에서효능

(efficacy)

와독성

(toxicity)

에대한정보를 제공할수있고

,

^{이러한정보를바탕으로하여환자군에대한임}

상적호전또는악화에대한평가를할수있다

.

^{이렇게얻은데}

이터를바탕으로하여총체적인영향력평가를할수있다

.

⁴⁾ 임 상결과변수와역학적

,

^{병태생리학적}

,

^{치료학적으로연관을가}

진생체표지자

,

^{즉올바른대리결과변수를선택하는것은매우}

중요하다

.

대리결과변수로서생체표지자가임상결과변수와 의관계는아래

4

^{가지로분류할수있다}

(Table I).

⁵⁾

Table I

에있는

A type

은생체표지자와치료의정도가상호관

련이없는관계로서대리결과변수로사용할수없는생체표지 자를 의미한다

.

^{전립선암의 생체표지자 중}

prostate-specific

antigen

^{은전립선암을밝힐수있는유용한생체표지자이나치료}

의정도를표현할수없으므로이에해당된다

. B type

은생체표

Fig. 1 −

Relation of surrogate endpoints and biomarkers.

³⁾

Fig. 2 −

Relationship of biomarkers and surrogate endpoints and

conceptual model for therapeutic intervention (BDWG).

⁴⁾

지자를통하여치료의정도를완벽하게판단할수있는관계로 서가장이상적인생체표지자라고할수있으며대리결과변수 로사용할수있다

.

^{현재까지이러한생체표지자는아직발견되}

지않았다

. C type

^{은생체표지자가임상결과변수와는직접적}

인관련성이있지만질병의치료에는직접적으로관련되지않은 유형이다

.

치료의정도에독립적으로영향을주는관계로서치

료에전적으로영향을주지는못한다고볼수있다

. C type

^은대

리결과변수로서사용할수있으나치료학적효과에대한과정 을설명할수없다

.

대부분시험에사용중인대리결과변수가

이에속한다고할수있다

. D type

^{은생체표지자에게는유의한}

영향을주지만치료의정도에는유의한영향을주기힘든관계 로서대리결과변수로서생체표지자를사용할수는없지만실 험적인측면에서의생체표지자로서사용가능한

type

^이다

.

^심근

경색에따르는부정맥의생체표지자로서심실성기외수축이이 에해당된다

.

⁵⁾

위에서언급한데로임상시험및가교시험에사용될수있 는생체표지자의경우

B

타입과

C

타입으로한정할수있다

.

임상 적으로나타날수있는결과의다양성과임상결과변수끼리의 상호작용을고려할경우

B

타입에적합한대리결과변수를찾는 것은극히드물것으로예상된다

.

그러므로

C

타입의생체표지자 개발및선정에중점적인연구가이루어져야할것이다

.

⁵⁾

FDA

^{및선진국의최근신약개발의}

critical path and Model- based drug development

Critical path

^{− 매년신약개발을위한투자비용은증가하는}

반면신약의허가는감소또는정체하는추세이다

. 2000

^년을전

후로이러한현상은더욱가속화되었으며신약물후보군발굴 단계에비하여신약개발의속도를결정하는단계인전임상및임 상시험을위한비용및기간은더욱더늘어나고있다

.

^그러므로

FDA

는신약개발방법의효율성향상을위해기존의경험에의

존한신약개발방식을탈피하여근거에기반한과학적이고효 율적인신약의개발

(model-based drug development)

^을위한모

든방법및도구를

critical path

라명명하고이에대한정보등

을제공하고있다

. '

^{생체표지자및질병모델의개발을통한진}

보된유효성

,

^{안전성평가기술의개발및적용}

'

^{의발전및적용}

을위한

critical path

의도구로서

biomarker, PK/PD modeling

및임상시험설계등이명시되어있다

.

⁶⁾

Model-based drug development

^{− 앞으로의신약개발과정}

에서효율성확보를위해서는성공적인임상시험수행및각개 발단계에서의시험성공예측력확보가반드시필요하고

,

^이를

위해서는기존의신약개발방식과는다른새로운관점의신약 개발접근이필요하다

.

이러한새로운관점의신약개발과정중

중요한 부분이 모델 기반학적신약 개발

(model based drug

development)

^이다

.

^{모델기반학적신약개발은전임상및임상}

시험수행을위해수학적모델을설정하고설정된모델을바탕 으로시뮬레이션을통해예측력을확보함으로써신약개발의결 정과정을보다객관적으로만들어준다

.

⁷⁾

Fig. 3

은모델기반학 적신약개발의연구흐름도로서기존의신약개발의방식과는 다르게설정된모델을적극적으로활용하여예측력확보및시험 디자인의개발

,

^{시험결과의해석등에사용하고}

,

^{얻어진결과를}

사용하여보다견고한모델을확보함으로써재임상시험또는다 Table I −

Type of relationship between biomarker and clinical

endpoint

A type

B type

C type

D type

I : Affected by intervention X : Not affected by intervention U : Unintended effect of intervention

Fig. 3 −

Research sequence model-based drug development.

⁷⁾

른임상시험에보다많은사전정보를제공할수있다

(Fig. 3).

⁷⁾

생체표지자

(biomarker)

^{및 대리 결과 변수}

(surrogate end- point)

^{의적절한사용및모델링과시뮬레이션기술사용을통해얻을}

수있는효과

2002

년도미국제약협회

(PhRMA)

회원사의

R&D

비용은

321

억달러이었으며

, 2008

^{년까지매년}

8%

^{씩비용이증가한다고발}

표하였다

.

그리고

2004

년도신약개발프로젝트들의

10%

가생

체표지자에의해영향을받을것으로예측하였고

, 2008

년에는

50%

^{로예상하였다}

.

^{생체표지자로인해도움을받는프로젝트들}

의개발비용은

2004

년도에는

15%

로시작하여

2008

년에는

45%

까지증가할것으로예상하였다

.

^{이러한계산으로예측할경우}

생체표지자의적극적인활용을통해비용을

23%(321

^억달러기

준으로하여

115

억달러절감

)

이상절감할수있는경제적효

과가있다

.

⁸⁾

Fig. 4

은모델링

,

시뮬레이션기술이기존신약개

발의단계에서활용가능범위를나타내고있다

.

^모델링

,

^시뮬레

이션기술의적극적인활용은신약개발의연구기간의단축뿐 아니라임상시험성공률을높임으로써수천억원에달하는신

약개발연구비를절감할수있는경제학적효과가있다

(Fig. 4).

⁹⁾

본종설에서연구하고자하는당뇨병의경우에도당뇨병최신

치료제인

DPP-IV

^{저해제개발시적절한생체표지자와모델링}

기술사용을통해약물의초기임상시험단계의단축효과를나 타낸사례가있다

. DPP-IV

저해제인

sitagliptin

개발의경우

,

기 존임상

1

^상과

2

^{상에소요되는시간이약}

3.5

^{년정도걸리는것}

에비하여적절한생체표지자의사용과모델링기술을통해기존 기간보다

1.4

년정도단축한

2.1

년의개발소요기간이걸렸다

.

¹⁰⁾

이러한경제적측면뿐아니라임상가설의조기검증과조기에 임상용량범위설정이가능토록함으로써제

1

^상및제

2

^상임상

시험에서의안전성및유효성을과학적으로확보할수있는시험 기술적측면의긍정적인영향을줄수있으며

,

^{환자반응성을정}

밀하게예측함으로써피험자의수를줄일수있는효과가있어임 상시험에서가장큰문제로인식되고있는피험자윤리에대한문 제를부분적으로극복함으로서임상시험에활성화를도모할수있다

.

당뇨병과 골다공증의 생체표지자 (biomarker) ^및

대리 결과 변수 (surrogate endpoint)

당뇨병의 임상 결과 변수

(clinical endpoint)

^{와 생체표지자}

(biomarker)

^{및대리결과변수}

(surrogate endpoint)

당뇨병의임상결과변수

(clinical endpoint)

^{− 당뇨병의임상}

결과변수는이환률

(morbidity)

의감소

,

당뇨성신경병증

(diabetic neuropathy),

^사망

(death),

^시각장애

(visual impairment),

^신부전

(kidney failure)

^{으로설명할수있다}

.

약물군에따른당뇨병의생체표지자

(biomarker)

^{의분류 −}

생체표지자는약물군별로다양하게존재한다

.

약물군은크게인 슐린요법

(insulin therapy),

^{설포닐유리아계}

(sulfonylurea),

^비구

아나이드계

(biguanide),

알파 글루코시데이즈 저해제

(alpha- glucosidase inhibitor),

^{티아졸리딘계}

(thiazolidinedione),

^메글리

티나이드계

(meglitinide),

^{엑세나타이드계}

(exenatide),

^아밀린계

(amylin analogue), DPP-4

저해제

(DPP-IV proteinase inhibitor)

그리고유전적생체표지자로나눌수있다

. Table II

^{에서알수있}

듯이각약물군별로다양한생체표지자를가지고있으며특징적 인점은대부분의약물이혈중인슐린농도와혈중포도당농도 를생체표지자로가지고있다는점이다

.

^{그중대리결과변수는}

Table II

에서보듯이혈중포도당농도

,

당화헤모글로빈

(HbA

1c

),

혈중인슐린농도

, adiponectin

등으로소수이다

(Table II).

인슐린요법 − 당뇨병은인슐린의분비량이부족하거나정상 적인기능이이루어지지않아혈중포도당농도가높아져소변 에포도당을배출하는질환이다

.

따라서당뇨병이있는환자들

은혈중포도당농도가높고인슐린의분비량이부족하다

.

^11-13)

또한당뇨병이있는사람들은대부분당화헤모글로빈을가지고 있다

.

따라서포도당농도

,

인슐린농도그리고당화헤모글로빈 수치는당뇨병과의 깊은연관성을가지므로생체표지자이자

동시에대리결과변수라할수있다

.

^11-13)

2

형당뇨병의경우

인슐린의양의문제보다는인슐린저항성내재인자가중요한 원인으로작용하는데이를나타내주는지표가당뇨병의치료에 중요한역할을할것으로기대된다

.

인슐린저항성을나타내는 지표는

HOMA-R(homeostasis model assessment of insulin resistence), OGTT(oral glucose tolerance test)

^수치

, QUICKI (quantitative insulin sensitivity check index)

이있다

. OGTT

를 나타내는수치는

ISI-composite, Stumvoll index, OGIS index

^로

세분된다

.

^{13, 14)}

Sulfonylurea

계 약물 −

Glyburide, glipizide, glimepride

등의 성분을포함하는설포닐우레아계약물의주된기전은인슐린분 Fig. 4 −

Objective of drug development to steps and a role of

modeling, simulation.

⁹⁾

Table II −

Biomarker and surrogate endpoint of diabetes mellitus

Disease Drugs Biomarker Surrogate endpoint Reference

Diabetes Mellitus

Insulin therapeutics

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 48, 53 Insulin resistant intrinsic factor

(HOMA-IR, OGTT, QUICKI) 11, 13, 14, 53

HbA

1c

HbA

1c

53, 54, 55, 56, 57

Insulin concentration in plasma Insulin concentration

in plasma 53

C-reactive protein (CRP) 16, 58, 59

Sulfonylurea

Insulin resistant intrinsic factor

(HOMA-IR, OGTT, QUICKI) 11, 13, 14, 15, 53, 60

HbA

1c

HbA

1c

53, 54, 55, 56, 57, 61, 62, 63, 64

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 15, 16, 60, 61,62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75,

76, 77 Insulin concentration in plasma Insulin concentration

in plasma 15, 53, 60, 61, 63, 68, 69, 70, 71, 72, 73, 74, 77

C-reactive protein (CRP) 16, 58, 59

Biguanides

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 17, 18, 19, 48, 53, 61, 63, 64, 78

Insulin resistant intrinsic factor

(HOMA-IR, OGTT, QUICKI) 11, 13, 14, 19, 53

HbA

1c

HbA

1c

18, 19, 53, 54, 55, 56, 57, 61, 63, 64 Insulin concentration in plasma Insulin concentration

in plasma 18, 53, 61, 63

C-reactive protein (CRP) 16, 58, 59, 63

Alpha-glucosidase inhibitor

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 11, 12, 20, 21, 48, 53 Insulin concentration in plasma Insulin concentration

in plasma 20, 21, 53

HbA

1c

HbA

1c

20, 21, 53, 54, 55, 56, 57

Glucosetransporter;

GLUT-2, GLUT-4 21

Alpha-glucosidase 21

Thiazolidinediones

cDNA encoding the protein (Acrp30; specific PPAR-gamma

biomarker, Adiponectin) Adiponectin 19, 22, 61, 79, 80 Insulin resistant intrinsic factor

(HOMA-IR, OGTT, QUICKI) 11, 13, 14, 19, 53

HbA

1c

HbA

1c

19, 53, 54, 55, 56, 57, 61, 64

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 19, 48, 53, 61, 64 Insulin concentration in plasma Insulin concentration

in plasma 19, 53, 61

serum total cholesterol,

HDL, LDL, triglycerides 18, 81

Meglitinides (short acting insulin secretion stimulating

agents)

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 26, 48, 53, 64

HbA

1c

HbA

1c

53, 54, 55, 56, 57

Insulin concentration in plasma Insulin concentration

in plasma 53

비촉진이다

.

¹⁵⁾인슐린분비가촉진됨으로인해서포도당의농도 와당화헤모글로빈이모두영향을받으므로설포닐우레아계약 물은인슐린

,

^포도당

,

^{당화헤모글로빈을생체표지자로활용한약}

물이라할수있다

. Smirnakis

등

(2007)

은당뇨병이심해질수록

염증시나타나는

CRP(C-reactive protein)

도증가하는것을연

구하였다

.

^따라서

CRP(C-reactive protein)

^{도당뇨병에작용하는}

생체표지자이다

.

¹⁶⁾

Biguanides

계약물 − 간에서당생성을강력하게억제하여혈

중포도당의농도를조절하는약물로서

metformin

^{으로대표된}

다

. Biguanide

계약물군의생체표지자는인슐린

,

포도당

,

당화헤

모글로빈

, CRP(C-reactive protein)

가있다

.

^17-19)

Alpha-glucosidase inhibitor

⁻

Bischoff

^등

(1995)

^은

alpha- glucosidase

저해제의기전에대해연구하였다

. Alpha-glucosidase

는탄수화물의소화에관여하는효소로서탄수화물의분해에관 여하여혈중포도당을만드는데결정적인역할을하는효소이다

.

따라서당뇨병환자의혈당조절에응용될수있는중요한생체 표지자로서제시될수있다

.

^20,21)

Glucose transporter(GLUT)

^도

중요한생체표지자로서응용될수있다

.

Thiazolidinediones

계 − 인슐린저항성을개선시켜표적조직

(

골 격근과지방세포

)

^{에서인슐린작용성을증가시키는약물군이다}

.

주로지방세포에서발현되는

PPAR-

γ

(peroxisome proliferators-

activated receptor)

를활성화시켜인슐린저항성을개선시킨다

.

PPAR-

^{γ와관련된}

adiponectin

^{이당뇨병환자에게서정상인에비}

해 떨어진다는 연구결과가 있다

.

²²⁾ 위 내용을 종합해보면

adiponectin

과 인슐린저항성내인적인자

(HOMA-IR, OGTT,

QUICKI)

^{은당뇨병치료제개발시유용하게응용할수있는생}

체표지자라할수있다

.

DPP-IV Proteinase inhibitor

⁻

DPP-IV(dipeptidyl peptidase- 4)

^{는혈당조절물질인}

GLP-1(glucagons-like peptide-1)

^과

GIP (glucose-dependent insulinotropic peptide)

를급속하게감소시

키는물질이다

.

따라서

DPP-IV

를저해시킴으로서

GLP-1

과

GIP

의기능을정상화시켜혈당조절을원활히조절할수있다

. DPP- IV proteinase inhibitor

는

sitagliptin

으로대표될수있다

.

^23-25)이

약물군은

DPP-IV

의활성도와

GLP-1

을생체표지자로활용한경

우라할수있으며이를응용해더많은당뇨병치료제의개발 이가능할것이다

.

기타약물군 − 이외에도

meglitinide

^계

(

^{단기간인슐린분비촉}

진제

), exenatide

^계

(GLP-1),

^아밀린계

(amylin analogue)

^당뇨병

치료제가있다

.

^26-29)이들은특징적인생체표지자는없었고당뇨

병의보편적인생체표지자인포도당농도

,

^{인슐린농도그리고}

당화헤모글로빈수치를생체표지자로활용하였다

.

골다공증의 임상 결과 변수

(clinical endpoint)

^{와 생체표지자}

(biomarker)

^{및대리결과변수}

(surrogate endpoint)

골다공증의임상결과변수

(clinical endpoint)

^{− 골다공증의}

임상결과변수는골밀도

(bone mineral density, BMD)

^의증가

,

Table II −

Continued

Disease Drugs Biomarker Surrogate endpoint Reference

Diabetes Mellitus

Exenatide (Glucagons-like

peptide-1)

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 27, 28, 48, 53,

Insulin reaction 28

Amylin analogues Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 29, 48, 53 Genetic biomarkers cDNA encoding the protein

(Acrp30; specific PPAR-gamma

biomarker, Adiponectin) Adiponectin 22, 79, 80

DPP-IV Proteinase inhibitor

C-reactive protein (CRP) 16, 23, 58, 59

Insulin-like growth factor-1

(IGF-1) 23

Insulin like growth factor binding

protein-3 23

DPP-4 activation in plasma 23, 24, 25

Total Glucagon-like peptide-1 (GLP-1)

concentration in plasma 23, 24, 25

Glucose concentration in plasma Glucose concentration

in plasma 11, 12, 16, 23, 48, 53

Glucagon concentration in plasma 23

Insulin

concentration in plasma 23, 53

수질골구멍크기

(trabecular pore size)

^{의감소로설명할수있}

다

.

^{30-32)그리고중요한임상결과변수의하나로통증의정도}

(pain level)

와

QOL(quality of life)

를들수있다

. QOL

은

Visual Anlogue Scale(VAS), Modified Face Scale(MFS), Beck Depression Index(BDI), Nottingham Health Profile(NHP)

으로 측정할수있다

.

³¹⁾

검출방법에따른골다공증의생체표지자

(biomarker)

^{의분류 −}

검출방법에따라

imaging marker,

혈청표지자

(serum marker),

뇨중표지자

(urinary marker)

로나눌수있다

. Imaging marker

는

MRI(magnetic resonance imaging), XTM(X-ray tomographic microscopy), DXA(dual X-ray absorptiometry)

등으로 관찰될 수 있는 생체표지자를의미한다

. Imaging marker

^로는

bone mineral density(BMD), micro-architecture deterioration, tra-

becular pore size

를들수있다

.

혈청표지자는혈청에서얻어질

수 있는생체표지자를의미한다

.

혈청 표지자는

C-terminal telopeptide of collagen type I(ICTP), osteocalcin(

^효소

), total alkaline phosphatase activity(ALP), bone isoenzyme alkaline phosphatase activity(boneALP), C-terminal propeptide of procollagen type I(PICP)

^{이 포함된다}

.

^{뇨중 표지자}

(urinary

marker)

는뇨중에서얻을수있는생체표지자를의미한다

. N-

terminal telopeptide of collagen type I(NTx), N-terminal propeptide of procollagen type I(PINP), deoxypyridinoline, hydroxy proline, proline-hydroxy proline dipeptide

가이에포함 된다

.

³³⁾

기전에따른골다공증의생체표지자

(biomarker)

^{의분류 − 기}

전별로는 골재흡수와관련된생체표지자

(biomarker of bone resorption),

^{골형성과 관련된 생체표지자}

(biomarker of bone

formation),

^{골밀도와 관련된 생체표지자}

(biomarker of bone

densitometry)

로구분될수있다

.

골 재흡수와 관련된 생체표지자는

serum C-terminal telopeptide(ICTP), urinary N-terminal telopeptide(NTx) of collagen I

이다

.

골형성과관련된생체표지자는

serum C-terminal (PICP)

^과

N-terminal(PINP) propeptides of procollagen I, bone-specific alkaline phosphatase, osteocalcin

이다

.

그리고골 밀도와관련된생체표지자는

bone mineral density(BMD)

가해 당된다

.

³³⁾

약물군에따른골다공증의생체표지자

(biomarker)

^{의분류 − 생}

체표지자는약물군별로다양하게존재한다

.

약물군은칼시토닌

(calcitonin),

^{에스트로겐대체요법}

(estrogen replacement therapy, ERT),

비타민

K

요법

,

비타민

D

요법

, bisphosphonate

계약물

, benzothiophene

^{계 약물}

,

^스트론튬

(Sr ranelate)

^요법

,

^그리고

statin

^{계약물을이용한요법이있다}

(Table III).

Calcitonin

− 칼시토닌은혈액속의칼슘량을조절하는호르몬

으로서갑상선

C

세포에서분비된다

.

혈액속의칼슘의농도가과

다할경우칼슘의농도를저하시키는역할을한다

.

^{따라서칼시}

토닌을이용하여골소실을억제하는효과를기대할수있다

.

^이

러한원리를응용해실제적으로칼시토닌을골다공증에이용하

는요법이있다

. Ellerington

^등

(1996)

^{은폐경기골다공증환자를}

대상으로 연어칼시토닌의비강 내주입을 이용하여위약군

(placebo)

과유의한차이가있는지를연구한사례가있다

.

그결

과골밀도가위약군과비교하여증가함을확인할수있었다

.

^따

라서칼시토닌이골다공증의치료에중요한역할을할것으로기 대된다

.

³⁰⁾또한

Ofluoglu

등

(2007)

은최근에골다공증의주요임 상적증상이라할수있는허리통증과

QOL

^{에관한칼시토닌의}

작용을연구하였으며

,

칼시토닌과베타엔도르핀

(

β

-endorphin)

의 연관성을연구하였다

.

^{그결과칼시토닌이베타엔도르핀의형}

성을유도하여통증경감의효과가있는것을

QOL

^{를측정함으로}

서 증명하였다

. QOL

은

Visual Anlogue Scale(VAS), Modified Face Scale(MFS), Beck Depression Index(BDI), Nottingham

Health Profile(NHP)

^{으로측정한다}

.

^{31)칼시토닌을이용한골다}

공증의 효과를 확인하는방법으로

MRI(magnetic resonance

imaging)

^{를이용한방법도있다}

.

^{수질골구조}

(trabecular micro- architecture)

^{를직접확인하는방법으로}

Chesnut 3

^rd등

(2005)

^이

이를연구하였다

.

³²⁾이렇듯칼시토닌을이용한치료요법에사용 되는골밀도와수질골구조는골다공증의중요한생체표지자라 할수있다

.

ERT(estrogen replacement therapy)

− 폐경기이후여성들에 게서자주나타나는골다공증의경우에스트로겐을보충해줌으 로서골다공증을치료할수있다

. Lane

등

(1999)

은난소절제술

을한암쥐에군별로

17

β

-estradiol

을단계별로주입하여수질골

부피

(trabecular bone volume)

^{를비교함으로서}

17

^β

-estradiol

^의

골다공증에미치는영향을조사하였다

.

^{수질골크기는}

3

^차원적

X-ray tomographic microscopy(XTM)

으로측정하였다

.

그결과 에스트로겐결핍시수질골크기에결함이생긴다는것을알수 있었다

.

^{34)골다공증환자에겐수질골에결함이생기므로수질골}

이골다공증의생체표지자라할수있다

.

이외에도에스트로겐 대체요법으로확인할수있는생체표지자는혈청생체표지자로 서는

C-terminal telopeptide of type I collagen(ICTP)

이있으며

,

뇨생체표지자로서는

deoxypyridinoline(DPD)

이있다는것을

Okabe

^등

(2004)

^{의연구결과에서알수있다}

.

³⁵⁾

비타민

K, D

요법 − 비타민을통해서골다공증을치료할수있

다

.

비타민

K

는뼈의석회화에중요한역할을한다

.

오스테오칼

신

(osteocalcin)

^{은우리의뼈안에서찾을수있는주요한비콜라}

겐단백질

(noncollagen protein)

이다

.

비타민

K

는오스테오칼신 분자를칼슘과결합시키고

,

^{칼슘이뼈안에서제자리에있을수}

있도록만드는데필요하다

.

^비타민

D

^{는칼슘과인의흡수를촉}

진

,

조직중의인산을칼슘과결합시켜뼈에침착시키는작용을 한다

.

따라서비타민

K

와비타민

D

가골다공증치료에응용될

수있다

. Matsunaga

등

(1999)

은폐경기여성의골다공증치료에 비타민

K

와비타민

D

의영향을연구하기위해난소를절제한 쥐를이용해

5

^{군으로나뉘어연구를하였다}

. 1

^군

(

^{난소절제한쥐}

), 2

군

(

난소절제한쥐

+

비타민

K

주입

), 3

군

(

난소절제한쥐

+

비타 민

D), 4

^군

(

^{난소절제한쥐}

+

^비타민

K+

^비타민

D), 5

^군

(

^위약군

)

^으

로나뉘었다

.

^결과로

2

^군과

3

^{군은골소실이비교적나타나지않}

았고

4

군은골소실이현저히줄어들었다

.

나머지

1, 5

군은골소 실이나타났다

.

^{이로부터비타민}

K

^와

D

^{가함께작용할때효과}

가극대화된다는것을확인할수있었다

.

^{위실험으로부터비타}

민

K

와

D

가오스테오칼신에작용하여골소실을억제한다는결 론을도출할수있으므로오스테오칼신을생체표지자로활용한 경우라할수있다

.

^{36)이외에도골다공증과관련하여}

proline dipeptide, hydroxy proline, bone alkaline phosphatase, pro- collagen c-terminal propeptide

^{의변화가있으므로골다공증에}

응용될수있는생체표지자라할수있다

.

^37-40)

기타약물군 −

Adachi

등

(2001)

은

alendronate

를용량별로투약 하고골밀도를측정해봄으로서

alendronate

^{의효과를알아보았}

다

. Alendronate

로대표되는

bisphosphonate

계약물도골밀도를 생체표지자로활용했다

.

⁴¹⁾

Benzothiophen

^{계약물을통해서는오스테오블라스트}

(osteoblast)

와오스테오클라스트

(osteoclast)

의변화를확인할수있다

.

오스 테오블라스트는조골세포로서

raloxifene

^{을통해증가되고오스}

테오클라스트는파골세포로서

raloxifene

^{을통해감소되는양상}

을 보인다

. Benzothiophen

의유도체인

raloxifene

은

selective estrogen receptor modulator(SERM)

^{으로서선택적에스트로겐}

항진작용을하는약물이다

.

^{그중골조직에에스트로겐항진작}

용이선택적으로작용하고이외젖샘이나요도에는길항작용을 한다

.

⁴²⁾

비방사성스트론튬의

2

^{원자와라넬릭산}

(ranelic acid)

^의복합

체인

Sr ranelate

은골의재흡수과정을저해하여골소실을억제

하는 작용을 한다

.

^{42) 이외에도}

trabecular pore size, bone mineral content(BMC), trabecular number

도영향을미친다

.

⁴²⁾

3-Hydroxy-3-methylglutaryl coenzyme A(HMG CoA) reductase

inhibitor

^인

statin

^{계열의약물도골밀도를증가시키는작용을한}

Table III −

Biomarker and surrogate endpoint of osteoporosis

Disease Drugs Biomarker Surrogate endpoint Reference

Osteoporosis

Calcitonin Bone mineral density (BMD) Bone mineral

density (BMD) 30

Micro-architecture deterioration 31,32

Estrogen replacement therapy (ERT)

Trabecular pore size 34

C-terminal telopeptide of type I

collagen (ICTP) 35

Deoxypyridinoline (DPD) 35

Bone mineral density (BMD) Bone mineral

density (BMD) 35

Vit K therapy Osteocalcin 36

Vit D therapy

Proline dipeptide 37

Hydroxy proline 37, 38

Bone alkaline phosphatase 39

Procollagen c-terminal propeptide 40

Osteocalcin 36

Bisphosphonate

(alendronate sodium, etidronate) Bone mineral density (BMD) Bone mineral

density (BMD) 41

Benzothiophene {selective estrogen receptor modulators

(SERMs)} (Raloxifene)

Inhibiting production of osteoblasts 42

Inducing the activity of osteoclasts 42

Sr ranelate

Bone resorption 42

Trabecular pore size 42

Bone mineral content (BMC) 42

Trabecular number 42

Statin (fluvastatin, atorvastatin,

simvastatin, pravastatin, lovastatin) N-terminal telopeptide 43

Bone mineral density (BMD) Bone mineral density (BMD) 43

다

. Fluvastatin, atorvastatin, simvastatin, pravastatin, lovastatin

^으

로대표되는

statin

^{계열의약물은}

cholesterol

^{의생성억제작용을}

주효과로사용되고있지만최근에

HMG CoA reductase inhibitor

작용이골밀도를증가시키는작용이있는것으로밝혀졌다

.

⁴³⁾

당뇨병과 골다공증의 생체표지자 (biomarker) ^및

대리결과변수 (surrogate endpoint) ^의 validation

Validation

^의과정

Surrogate endpoint validity

^{− 임상시험에일반적으로사}

용되기위해서는대리결과변수에사용하기위한생체표지자의 데이터의정확성

(accuracy)

^및정밀성

(precision)

^{을확보해야한}

다

.

^{데이터의정확성과정밀성뿐아니라아래와같은}

validation

도필요하다

.

대리결과변수와임상결과변수사이에나타나는

현상이비슷한정도를의미하는

face validity,

임상결과에영향을

줄수있는변수들의안정적인상태에서와영향력

(intervention)

에따른변화도간의상관성정도를의미하는

criterion validity,

대리결과변수와임상적결과사이에는메커니즘적인공통점 있어야한다는

construct validity

^{이필요하다}

.

⁴⁴⁾

Fit-for-Purpose validation

^{− 연구또는실험목적에적합한}

생체표지자를선정하기위하여정성및정량법의표준화및평 가하는과정이다

(Fig. 5).

^45-48)

Fig. 5

^에서의

exploratory method

validation

은빠른시간에생체표지자를검색하기위해실험목적

에적합한최소한의기준에근거한발리데이션을 의미한다

.

Advanced Method validation

은추후약물개발과정에서결정적

인개발방향을제시하기위한발리데이션방법으로서

exploratory

method validation

^{에비하여엄격한기준에근거하여평가하는}

방법이다

.

Fit-for-purpose validation

확보를위한구성요소에는표준액

및시약에대한

validation(

^{안정성및시약교체에따른효과등}

),

생체표지자의 분석을 위한

target range

^에서의

validation, Sensitivity,

검량선

fitting

방법

(linear, non-linear method

등

),

희

석효과의 측정

,

^{분석법의 정확성및정밀성확보}

,

^분석법의

robustness

^와

reproducibility,

^{샘플의조작법과채취과정및방법}

,

저장법에대한

validation,

전과정의문서화과정이포함된다

.

Validation

^{의단계 − 기존의 생체표지자의단계를분석법의}

validation

정도와임상 결과변수와의연관성 등을고려하여

exploration, demonstration, chracterization, surrogacy

단계로 세분화하여설명할수있다

.

⁴⁹⁾

•

Exploration step :

연구및개발을위한생체표지자로서 in vitro

/pre-clinical

시험에정보를주지만임상적인연관성은부족한 경우를의미하며가설의생성및검증에이용할수있고당뇨병 의생체표지자중

gene expression

이이에해당한다할수있다

.

•

Demonstration step :

^충분한

preclinical

^{감도와특이성}

,

^임

상과의연계성이관련되어있으나임상시험을통한재현성을확 보하지못한생체표지자로서일차적인

clinical evidence

로약물 개발단계에서

decision-making

의수단으로이용될수있으며당 뇨병의생체표지자중

adiponectin

^{이이에해당한다할수있다}

.

•

Characterization step :

충분한

preclinical

감도와특이성

,

임상 과의연계성이관련되어있고

1

^{회이상의임상시험을통해재현성}

이확보된생체표지자로서약물의치료용량및부작용에대한판 정과예방효과검토에모두적용가능한단계로당뇨병의생체표 지자중

fasting plasma glucose(FPG)

^{이이에해당한다할수있다}

.

•

Surrogacy step :

^{얻어진데이터를통해임상결과변수와}

생체표지자또는대리결과변수와의관계를규명하여임상결 과변수대신치환하여사용할수있는생체표지자로서신약의 허가단계에서유용하게이용될수있으며당뇨병의생체표지자 중당화헤모글로빈

(HbA

1c

)

이이에해당된다할수있다

.

Biomarker

^및

surrogate endpoint

^{개발및선정의시험흐}

름 − 위에언급된선행적문제및개념적모델을종합적으로고 려할경우해당질환및해당약물군에대한생화학적표지자및

대리결과변수선정을위한연구방법은

Fig. 6

^{과같은흐름도를}

Fig. 5 −

Research sequence of fit-for-purpose validation.

⁴⁵⁾

Fig. 6 −

Research sequence of surrogate endpoint.

⁵⁰⁾

Table IV −

Validity, proximity, specificity of diabetes mellitus bio- marker

Validity Proximity Specificity Insulin concentration in plasma - +++ +++

Fasting plasma glucose level - ++++ ++++

HbA

1c

level ++++ +++ +++

통해진행하여야한다

(Fig. 6).

⁵⁰⁾

당뇨병의생체표지자

(biomarker)

^{및대리결과변수}

(surrogate endpoint)

^의

validation

생체표지자가임상적결과변수와의연관성

(proximity)

^를고려

할경우당뇨병에사용될수있는생체표지자및대리결과변수 는혈중인슐린의농도

,

^{공복시의혈중포도당농도}

,

^당화헤모

글로빈

(HbA

1c

)

과같은것이사용될수있으며각생체표지자를

validity, proximity, specificity

등에비추어평가시공복시혈중 포도당레벨이가장의미있으나다른생체표지자와의영향력

(intervention)

고려시다른생체표지자의측정도의미가있다

.

가

령혈중인슐린의농도와

specificity

면에서겹치지않는경우에

는

Validity

^{가뛰어난당화헤모글로빈을생체표지자로측정하는}

것도의미가있을수있다

(Table IV).

⁵¹⁾

골다공증의생체표지자

(biomarker)

^{및대리결과변수}

(surrogate endpoint)

^의

validation

골다공증약물의경우기전에근거한

PK/PD model(mech-

anism based PK/PD model)

^{까지제시된당뇨병치료제와는다}

르게임상결과변수와연관성이큰

(proximal)

생체표지자는아

직개발단계에있다

.

임상결과변수와가장연관성이큰골밀

도

(bone mineral density, BMD)

^{를측정하는방법은인체에직}

접적으로적용하기어렵고

validity

또한어려워다른생체표지

자개발에주력하고있는실정이다

(Table V).

⁵²⁾

결 론

신약의개발보다제네릭약물의개발에초점이맞추어져있던

국내제약산업의특성상모델기반학적신약개발

(model-based

drug development)

^{의수준은초보적인단계에불과하다}

.

^하지만

제네릭의약품이국내제약사간의과다경쟁및특허를통한거 대제약회사의자사품목방어등으로인해국내제약사들도제 네릭의약품개발위주의정책에서점차신약개발에초점을맞 추고있으며국내대기업에의한국산신약도활발하게개발되 고있는실정이다

.

^{생체표지자와대리결과변수연구}

,

^개발의

적극적인활용이필요한비임상및임상시험에대한기반확충 및산업화가의약품산업발전의

10

^{대과제로선정됨에따라위}

기술에대한필요성은폭발적으로늘어날전망이다

.

국내의의 약품산업특성상가교시험의숫자도해마다증가하고있는현 상황에서생체표지자와대리결과변수의연구

,

^{개발에대한요}

구가사회전반에걸쳐확산되고있는실정이다

.

본종설연구는아직확립되지않은생체표지자와대리결과

변수에대한개념및필요성을

FDA

^{및선진국에서적용하고있}

는

critical path

^{를통해서제시하고그로인해파생되는효과를}

설명하였다

.

그리고실제당뇨병과골다공증에적용시켜봄으로 서당뇨병과골다공증의생체표지자를약물군별로연구

,

^조사하

여앞으로의당뇨병과골다공증의치료제개발연구에도움이될 것으로사료된다

.

그리고실제생체표지자의

validation

에대해 구체적인사항을연구

,

^{조사함으로서앞으로의새로운생체표지}

자의연구

,

개발에도움이될것으로생각된다

.

당뇨병과골다공 증은많은종류의생체표지자가조사되었지만여러종류의생체 표지자가대리결과변수의후보물질로서임상결과를대변할수

있는

marker

가되기위해서는정상군과당뇨병골다공증과의차

이또는질병의중등도에따른변화에대한연구가더많이수 행되어야하며나아가서궁극적으로는신생생체표지자의연구

,

개발및선정이꾸준히이루어져야한다

.

감사의 말씀

이논문은

2007

^{년식품의약품안전청용역연구개발사업}

"07082

Table V −

Characteristic of osteoporosis biomarker

Marker Method Ease of use Bone specificity Validity

Serum marker of bone formation

Total alkaline phosphatase Colorimetric ++++ - ++

Skelectal alkaline phosphatase ELISA ++ +++ +

Procollagen-I extension peptide RIA ++ +++ ++

Osteoclacin RIA, ELISA +++ +++ +

Urine markers of bone resorption

Calcium AA +++ - +++

Hydroxyproline Colorimetric ++ + +++

Total pyridinolines HPLC + ++ ++

Free deoxypyridinoline ELISA +++ +++ ++

N-telopeptide ELISA +++ +++ +++

C-telopeptide ELISA ++ ++ ++

RIA : Radioimmunoassay, ELISA : Enzyme-Linked ImmunoSorbent Assay, AA : Atomic Absorption spectroscopy, HPLC : High

Performance Liquid Chromatography

의약안

231-

^{생체표지자및대리결과변수의}

PK/PD

^모델링적

용에 관한연구

(The study for evaluation of PK/PD modeling using biomarker and surrogate endpoint)"

재원으로수행된연 구결과입니다

.

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