Clinically Actionable Biomarkers in Rheumatoid Arthritis

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1 Clinically Actionable Biomarkers in Rheumatoid Arthritis PepTalk January 6, 2009 William Robinson, MD, PhD Stanford University School of Medicine VA Palo Alto Health Care System

2 T cell mediated Autoimmune Diseases

3 Rheumatoid Arthritis Autoimmune synovitis % of U.S. population Anti-citrulline antibodies precede arthritis by up to 0 yrs Current therapies: -Small molecules: methotrexate, hydroxycholoquine -Biologicals: anti-tnf, anti-cd20, CTLA4-Ig

4 RA Pathogenesis RA Pannus Tissue

5 Citrullination (deimination) Autoimmune trigger? PAD Peptidylarginine (+) peptidylcitrulline (neutral) PAD Anti-CCP Vossenaar et al, 2004

6 Transfer of anti citrulline fibrinogen Ab exacerbates CIA Kuhn et al, JCI, 2006

7 Smoking and RA CCP+ RA CCP- RA Anti-citrulline smoker non-smoker Klareskog, A&R, 2006

8 Identification of Actionable Biomarkers for RA Hypothesis: Within RA there are molecular subtypes with differential responses to anti TNF, CTLA4 Ig, and anti CD20 therapy Actionable Biomarkers in RA: (i) (i) Early diagnosis Selection of therapy

9 First Generation Protein Microarray

10 RA Protein Arrays Print peptides and proteins 2304 features 500+ antigens: Vimentin Fibrinogen Keratin Filaggrin/CCP hnrnp A2, B, D HSPs 60, 65, 70, 90 H2B, H2A Collagens GPI BiP COMP gp39

11 Differential autoantibodyresponsesinra in RA- RA-2

12 Anti citrullinated protein antibodies are associated with elevated bloodcytokines TNFα-hi TNFα-lo IL-6-hi IL-6-lo

13 Elevated serum cytokines are associated with anti CCP, RF and SE in the ARAMIS inception cohort

14 Diagnostic and Therapeutic Approach in RA in 2008 Physical exam If Dx with RA: More tests: Empiric trial PMD orders Referred to - RF, CCP of small molecule basic tests: RF Rheumatologist - X-rays and then biological therapeutics Patient with early arthritis At 3 years: -30% work disability -2% social security Early RA Diagnostic: Early intervention induced remission in 56% of patients Diagnostic to Guide RA Therapy: Identify patients likely to respond to anti-tnf, CTLA4-Ig, anti-cd20

15 83 RA Cases with Pre-Arthritis Samples Department of Defense Serum Repository Cases (N=83) Age at Diagnosis of RA, Mean 39.9 Male, N (%) 49 (59%) Race, N (%) White 57 (69%) Black 2 (25%) Other 5 (6%) RA Classification Erosions, N (%) Present Absent Unclassified 8 (98%) 4 of 7 ACR criteria 4 (49%) 35 (42%) 7 (8%) Serum Samples (N=243) Mean (std) Range Number of pre-clinical samples per case Years before diagnosis of first sample 2.9 (.2) 6.6 (3.7)

16 Median Times of Appearance of Cytokines and Antibodies in CCP Positive Subset of RA Cases* Median time of symptom onset TNFalpha** RF-IgG** IL-alpha** Flt-3 Ligand** IP-0** IL-2p40 MCP- IL-2p40** RF-IgA** IP-0 RF-IgM CCP Years prior to diagnosis

17 Proposed Model for the Development of RA: Phase Phase 2 Phase 3 Environmental Exposures Genetic Risk Pre Clinical l Clinical lra Autoimmunity HLA PTPN22 CTLA 4 STAT 4 TRAF C5 Smoking Hormones Infections Anti CCP Anti cit fibrin RF MCP, IP 0 IL 6, IL, TNF CCP RF Anti cit fibrin CRP Multiple cytokines

18 Overview Anti TNF new start cohorts TNF blocker start ACR response to therapy Responders: ACR >= 50% Non Responders: ACR < 20% 0 3 months Pre Rx blood sample Post Rx sample

19 Pre treatment blood antibody profiles predict response to anti TNF (etanercept) therapy Non Responders Responders sl086 G005 NR sl4 G023 NR sl098 G05 NR sl08 G083 NR sl092 G25 NR sl0 G02 NR sl090 G093 NR sl02 G3 NR sl096 G087 NR sl04 G007 NR sl09 G089 ACR40 sl094 G36 NR sl07 G047 ACR80 sl095 G098 ACR40 sl2 G27 NR sl3 G065 ACR60 sl097 G049 ACR70 sl03 G069 ACR40 sl G23 ACR90 sl099 G067 ACR60 sl087 G035 ACR80 sl089 G059 ACR60 sl05 G2 ACR50 False discovery rate < 3%

20 Pre treatment blood antibody profiles predict response to anti TNF therapy isclassification Erro or M Individual CV Plots 6 antigens Threshold ACR50+ NR

21 Pre treatment elevations in blood cytokines provide additional utility for identifying anti TNF responders Score) Respo onse to anti TNF thera apy (Diseas se Activity Responders Non Responders Cytokine level (pg/ml)

22 Identification of Blood Biomarkers to Guide Anti TNF Therapy in RA Screening: ABCoN cohort n = 29 SAM Antigen Microarray Multiplex Cytokine ELISA validation PAM Validation: Swedish cohort n = 43 Japanese cohort n = 3 Ag ELISA Multiplex Cytokine PAM Ag ELISA Multiplex Cytokine

23 Biomarkers for guiding therapy and early diagnosis in RA Early RA Diagnosis Multiple antibodies are elevated >5 years pre arthritis, and isotype switching is associated with progression to arthritis Multiple chemokines are elevated years prior to clinical RA Predicting response to anti TNF Pre treatment Ab and cytokine profiles predict response to anti TNF Validation in Proteomic Discovery Statistical Analysis Independent Cohorts Miscl assification Error Individual CV Plots Threshold ACR50+ NR U.S. Cohort European Cohort Asian Cohort Transfer to clinical grade platform

24 Proteomics for diagnosis and guiding gtherapy MS IDDM Autoantibody & Cytokines Profiles RA Selection of therapeutics