Biomarkers in Osteoarthritis Ali Mobasheri - hstalks.com · • The Osteoarthritis Research Society International (OARSI) and the US Food and Drug Administration (FDA) have recently

Biomarkers in OsteoarthritisAli Mobasheri

1The screen versions of these slides have full details of copyright and acknowledgements

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Biomarkers in Osteoarthritis

Ali Mobasheri, D.Phil. (Oxon)Musculoskeletal Research Group

School of Veterinary Medicine and ScienceFaculty of Medicine and Health Sciences

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Aim and scope

• The aim of this presentation is to:Provide an overview of current research on osteoarthritis (OA) biomarkers

Highlight the lack of analytical tools and reagents in our toolbox

Discuss the limitations of currently available biomarkers

Explore future opportunities and identify key areas that are relevant to the pharmaceutical product pipeline

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Overview of presentation

• Summary of the definitions of OA and biomarkers of OA

• Need for a better “gold standard”:Radiography is inadequate

• Recent developments in biomarker definition and classification“Wet” and “dry” biomarkers

• Post-genomic approaches for identification of new OA biomarkers aimed at early (pre-radiographic) identification of disease

• The advent of “combination biomarkers”



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Background and context

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Osteoarthritis (OA)• Most common form of arthritis in humans

and companion animals Major cause of pain, inflammation and loss of mobility

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Osteoarthritis (OA) (2)

• Characterised by progressive deterioration and loss of articular cartilage

• Affects load-bearing synovial joints

• Associated with ageing and excessive or abnormal joint loading



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Osteoarthritis (OA) (3)

Other features:Synovial inflammation

Subchondral bone sclerosis

Osteophyte development (formation of bony outgrowths)

SynoviumSynovial fluid

Cartilage

Subchondral bone

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Risk factors for OA• Age

• Joint trauma

• Joint instability

• Genetics (breed in animals)

• Obesity

• Metabolic/endocrine disease

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Obesity and OA

• Strong evidence supports a link between obesity and OA

• Obesity is a complex metabolic and inflammatory syndrome Adipokines, (adipocytokines) play important rolesin the onset of disease

• Lifestyle changes for OA patients:Weight loss and calorie restriction

Gabay, Hall, Berenbaum, Henrotin and Sanchez (2008) Joint Bone Spine 75, 675-9Abramson and Attur (2009) Arthritis Res Ther 11, 227Iannone and Lapadula (2010) Curr Drug Targets 11, 586-98



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General features of OA

Synovial space (joint space narrowing) as assessed by radiography

Cartilage anabolism and impaired cartilage repair

Synovial inflammation and hyperplasia

Proteolytic activity (collagenases, gelatinases)

Cartilage degeneration

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Synthesis DegradationPhenotypic ModulationQuiescence Activation

Loss of homeostasis leads to osteoarthritis

TraumaInflammation

Genetic defectsAging

Articular cartilage

Calcified cartilage

Subchondral trabecular bone

Slide courtesy of Dr. Mary Goldring, Hospital for Special Surgery, New York

Articular cartilage

Subchondral cortical bone

Tidemark duplication

Vascular invasion

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The cytokine balance is perturbed in osteoarthritis

IL-1TNF-a

IL-17IL-18

LIFOSM

IL-6IL-8

IL-1rasTNFR

IL-4IL-10IL-13

IGF-IBMPsFGFsPGE2

Modified from MB Goldring, Kelley’s Textbook of Rheumatology, 8th Edition

Cartilage matrixdegradation

Cartilagematrix

synthesis

anti-TNF therapy for RA



13Goldring MB, Goldring SR. J Cell Physiol 2007; 213: 626-634

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Synovial, chondral and subchondral changes in OA

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Biomarker: definition

• A biomarker is a characteristic that is objectively measured and evaluated as an indicator of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention



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Rationale for the identification and development of osteoarthritis biomarkers

Why do we need new OA biomarkers?

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The gold standard (radiography) is inadequate

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A better “gold standard”

• OA is often diagnosed radiographically when the clinical signs of pain and loss of mobility have already appeared

Unfortunately by this stage the disease has progressed extensively and cartilage degradation is significant

We need better methods and assays to predict OA progression and responses to therapy



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Limitations of radiography

• Indirect measure of alterations in articular cartilage

• Fails to measure a dynamic process

• Changes overtime are small, and occur in only a subset (progressors) of patients

• Poor reproducibility

• Poor correlation with joint function and pain

• Numerous other confounders

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Rationale for identifying early osteoarthritis biomarkers

• Early detection will facilitate earlier diagnosis and treatment because OA which is characterised by a prolonged pre-clinical ‘molecular’ phase, a ‘pre-radiographic’ phase, and a ‘recalcitrant radiographic’ phase by which time there are extensive structural changes to joints along with pain and loss of function

• Biomarkers could provide an early warning of joint degenerationwhich could prompt earlier, more targeted treatment

Osteoarthritis and Cartilage 19 (2011) 515-542

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Classification of OA biomarkers: BIPEDs

Safety

Burden of Disease, Investigative, Prognostic,Efficacy of Intervention, Diagnostic, and Safety



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Osteoarthritis biomarkers network classification

(Bauer et al., 2006)BURDEN OF DISEASE MARKER

Biomarker associated with extent or severity of disease

INVESTIGATIVE MARKER

Biomarkers not yet meeting criteria for another category

PROGNOSTIC MARKER

Predict onset or progression

EFFICACY OF INTERVENTION MARKER

Indicative or predictive of treatment efficacy

DIAGNOSTIC MARKER

Differentiates diseased from non-diseased

SAFETY BIOMARKERS

Reflect tissue and/or organ toxicity of a agent or intervention

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Classification of OA biomarkers and the OA biomarkers working group

• The Osteoarthritis Research Society International (OARSI) and the US Food and Drug Administration (FDA) have recently established the OARSI FDA Osteoarthritis Biomarkers Working Group

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Classification of OA biomarkers

• The OARSI FDA Osteoarthritis Biomarkers Working Group has divided OA biomarkers into two major groups:

Soluble or ‘wet’ biomarkers

The ‘dry’ biomarkers

Biochemicals

RNA, DNA

MetabolitesProteins

Protein FragmentsPeptides

Soluble or « wet » biomarkers

Imaging, Questionnaire,

VAS

X-rayMRI Ultrasound

« Dry » biomarkers

WOMAC Lequesne

Slide courtesy of Prof. Yves Henrotin, Université de Liège



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The diagnostic and prognostic relevance of biomarkers for clinicians and patients

• Biomarkers have the capacity to detect early cartilage degradation in OA

• They can provide useful diagnostic information by:Reflecting disease relevant biological activity in the joint

Predicting the course of disease progression

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The relevance of biomarkers to the pharmaceutical product pipeline

Biomarkers can serve as surrogate endpoints in the drug discovery process

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The drug pipeline

Drug discovery is protracted, risky and costly



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Challenges facing the drug pipeline

• Convoluted – not linear

• “Leaky” – high levels of attrition

• Highly susceptible to the recession

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The OA drug pipeline

• Currently empty

• Nothing new to offer patients and the OA research community

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Surrogate OA biomarkers facilitate the drug discovery process

• Linking a biomarker to a clinical endpoint facilitates the drug discovery process

• Qualification is a process applied to a particular biomarker to support its use as a surrogate endpoint in:

Drug discovery and development

Post approval

Regulatory decision making



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• Quantifiable decision points – go/no-go decisions

• Use in translational medicine – bridging information

• Early identification of responders & non-responders

• Early quantification of first clinical efficacy

• Identification of those in need of treatment

• Selection of patients most likely to respond

• Dose determination – Phase II

• Safety and efficacy – cost/benefit ratio

• Differentiating compounds from competitors

• Drug repositioning

• Monitoring of patients – compliance

• Personalised health care (PHC)

• Pharmacovigilance

Applying the biochemical marker toolbox in drug discovery and development

Slide courtesy of Dr. Anne-Christine Bay-Jensen, Nordic Bioscience Company

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Biomarker Discovery

Verification §

Assay Development and Optimization

Validation ¶

Commercialization

Qualification *

§ Independent scientific and analytical verification of the biomarker – this process involves verification of the analytical performance characteristics and clinical correlation of a biomarker with a biological process or clinical outcome

* Linking a biomarker to a clinical endpoint –Qualification is a process applied to a particular biomarker to support its use as a surrogate endpoint in drug discovery, development or post approval and, where appropriate, in regulatory decision making

¶ Assessing all technical aspects of the biomarker assay

The biomarker pipeline

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Major classes of OA biomarkers

• Collagenous biomarkersFragments of collagens (particularly type II collagen)

• Non-collagenous biomarkers

Cartilage Oligomeric Matrix Protein (COMP)

• Hyaluronic acid (HA)

• Others:YKL-40 - chitinase 3-like 1 glycoprotein



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Soluble OA biomarkersBiomarker Process Tissues of origin BIPED Classification

uCTX‐II Catabolism of type II collagen and osteophyte burden

Mineralized and mineralized cartilage, growth plate cartilage, bone

Knee: B, P, E, DHip: B, P, D

s/u Coll2‐1 Type II collagen cleavage Cartilage Knee: D, B, PHip: D,

s/u Coll2‐1NO2 Type II collagen cleavage and nitration

Cartilage Knee: D, B, PHip: D

s/uC2C Type II collagen cleavage Cartilage Knee: E, DHip: B

s/uC1,2C Type I and II collagens cleavage

Cartilage, bone, synovium Knee: DHip: none

sCPII or PIICP Type II collagen synthesis Cartilage Knee: DHip: B

sPIIANP Type IIA collagen synthesis Cartilage Knee: B, P, D

sCOMP Cartilage metabolism and osteophyte burden

Cartilage, tendon, meniscus, synovium, osteoblasts, arterial wall

Knee: B, P, DHip: B, P, D

sHA Osteophyte burden, synovitis Cartilage, meniscus, synovium and ubiquitous in body

Knee: B, P, E, DHip: P

sKS Catabolic, aggrecan Cartilage Knee: B, P, E, DHip: none

sCS‐846 Anabolic, aggrecan Cartilage Knee: PsYKL‐40 Catabolic Macrophage, cartilage,

synovial, cells of epithelial origin.

Knee: B, EHip: D

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BIPED biomarkers classification

uCTX-IIsHA, sKS

sPIIANP,s/u Coll2-1NO2,

sCOMP, s/u Coll2-1

s/uC2C, uTIINE, sYKL-40,

uGlc-Gal-PYD

s/uC1,2C, sCPII, sCS-846, MMP-3, MMP-13

BPED

BPD

BP or BD or ED

sCOMP,

uCTX-II

sHA, s/uC1,2C, sCPII, s/u Coll2-1,

s/u Coll2-1NO2,s/uC2C, sYKL-40

KNEE HIP

B or P or E or D

The majority of biochemical markers has been investigated in knee OA

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Classification of cartilage biomarkers according to tissue of origin

The majority of OA biomarkers originate from cartilage but some biomarkers are found in other connective tissues

CartilageColl2-1, Coll2-1NO2, CPII, TIINE, PIIANP, C2C, C1, 2C, CTX-II, HA, KS, CS-846, COMP, YKL-40

Growth plate cartilage CTX-II, C1,2C

Bone CTX-II, COMP, C1,2C, NTX-I, CTX-I, PYD, DPD, OC

Meniscus COMP, HA, C1, 2C

Tendon COMP

Synovium COMP, HA, C1,2C, YKL-40, Glc-Gal-PYD



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Not all biomarkers are indicators of cartilage catabolism

The majority of OA biomarkers originate from cartilage but some biomarkers are found in other connective tissues

Cartilage catabolismColl2-1, Coll2-1NO2, CTX-II, COMP, C2C, C1,2C, TIINE, KS, CS-846, YKL-40

Cartilage anabolism CPII, PIIANP

Osteophyte burden CTX-II, COMP, HA

Synovitis/catabolism HA, Glc-Gal-PYD, PIIINP

Bone turnover NTX-1, CTX-I, PICP, PINP, PYD, DPD, OC, ICTP

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The matrisome

• The full complement of ECM proteinsThe “core matrisome” comprises ~ 300 proteins in addition to ECM modifying enzymes, ECM-binding growth factors, and other ECM-associated proteins

Cold SpringHarb Perspect Biol 2012; 4: a004903

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Biomarkers originate from different synovial tissues and cells



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Proteomic strategies to identify OA biomarkers

41J Proteomics 2012

ECM proteins

Proteins involved in inflammation and the immune response

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J Proteome Res 2011 Nov 4; 10(11): 5095-101

Complement proteins (alternative pathway)

COMP, Lumican, Tetranectin



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Complement proteinsas membrane biomarkers of OA

• The ‘membrane attack complex’ (MAC) component of complement has been implicated in the pathogenesis of OA

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Complement components are aberrantly expressed in OA

Nature Medicine 17, 1674–1679 (2011) doi:10.1038/nm.2543

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Current barriers to biomarkers achieving their full potential

• Lack of specificityTissue

Pathology

Affected joints

• Lack of disease modifying drugs that can impact disease progression

The drug and biomarker pipelines are mutually interdependent



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Challenges to OA biomarker discovery, validation and qualification

• Biomarker candidates frequently vary in the body with changes in:

Renal function (i.e., glomerular filtration rate)

Hepatic function

Food intake

Physical activity

Circadian rhythms

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Performance and measurement of markers are dependent on much more than the assay

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Summary

• Biomarker discovery and validation for OA have accelerated significantly over the past decade

• This information has contributed to our understanding of molecules from joint tissues, their complex interactions and how they end up in blood after being handled by the liver and kidneys

• The absence of new drugs for OA in the pharmaceutical discovery pipeline is, in part, due to a lack of biomarkers that can predict responses to candidate structure modifying drugs

• We need to expand our toolbox and develop new biomarker tools and reagents

• New OA biomarkers will relieve key bottlenecks in the drug discovery pipeline and facilitate drug development for this debilitating disease



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Conclusions

• There are currently no reliable biomarkers for early diagnosis of OA

• The existing biomarkers can only confirm what we know already (i.e., from radiography, the so-called “gold standard”)

• The challenge is to identify sensitive and reliable pre-radiographic markers that can be accurately and reproducibly measured in body fluids

• The assays should be robust and easy to establish in any laboratory

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Conclusions (2)

• Future research in OA biomarker discovery will need to focus on the identification and validation of panels of protein and/or metabolite biomarkers that correlate with a range of diagnostic imaging techniques such as:

Radiography

Ultrasound

Computed tomography (CT)

Magnetic resonance imaging (MRI)

• Ideally, such biomarkers will serve in non or minimally-invasive, reliable diagnostic and prognostic assays of disease severity and act as reliable monitors of the patient response to a range of different therapies

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Current progress and existing bottlenecks

• Proteomics is increasingly applied in cartilage biology and pathophysiology and the discovery of novel OA biomarkers

• Many existing biomarkers reflect catabolic and cartilage degradation in the later stages of OA

• Some biomarkers indicate normal cartilage turnover, tissue repair, or ECM remodelling

• We need to be able to discriminate between catabolic and maintenance events

• The definition of ‘biomarker’ will need to reflect these diverse processes and the validation and qualification processes will ultimately depend on the context and specific purpose of their intended applications



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Future priorities

• Development of new sophisticated analytical techniques for studying post-translational modifications in ECM molecules in OA

• Expanding the databases to allow detailed bioinformatic studies

Current databases are too small – size matters and small is not beautiful

• Refinement of bioinformatic tools and techniques to “mine” for information in databases

Machine learning

Clustering

Data visualisation

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Biomarker combinations

• Development of new “combination biomarkers” that include biochemical markers, and imaging markers(i.e., radiographs, MRI)

• OA may be diagnosed better and much more sensitively when two or more biomarkers are assayed and the data combined with one or more imaging modalities (i.e., plain radiograph and MRI)Williams, MK (2009) Biomarkers: in combination they may do better; Arthritis Research & Therapy, 11: 130 doi:10.1186/ar2839

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Biomarkers of joint overuse and injury

• Joint injuries sustained by athletes are a major risk factor for the development of OA

• Developing biomarkers for monitoring joint overuse and injury in athletes can help monitor responses to different therapies (i.e., corticosteroid, NSAIDs, surgery) and avoid further joint damage associated with overuse injuries



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The is in the

Take-home message

We need:• New biomarker targets

• Monoclonal antibodies

• Sensitive biomarker assays

• Affordable diagnostic kits

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Acknowledgements: funding and collaborators

Dr. Julia Smith

Dr. Susan Liddell

Dr. Jaume Bacardit

Professor Charlie Hodgman

Professor Yves Henrotin

University of Liège, Belgium

The D-BOARD Consortium

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Documents

Biomarkers in Osteoarthritis Ali Mobasheri - hstalks.com · • The Osteoarthritis Research Society International (OARSI) and the US Food and Drug Administration (FDA) have recently