Adam Platt

Biochemical markers of ongoing joint damage in rheumatoid arthritis - current and future applications, limitations and opportunities

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease associated with potentially debilitating joint inflammation, as well as altered skeletal bone metabolism and co-morbid conditions. Early diagnosis and aggressive treatment to control disease activity offers the highest likelihood of preserving function and preventing disability. Joint inflammation is characterized by synovitis, osteitis, and/or peri-articular osteopenia, often accompanied by development of subchondral bone erosions, as well as progressive joint space narrowing. Biochemical markers of joint cartilage and bone degradation may enable timely detection and assessment of ongoing joint damage, and their use in facilitating treatment strategies is under investigation. Early detection of joint damage may be assisted by the characterization of biochemical markers that identify patients whose joint damage is progressing rapidly and who are thus most in need of aggressive treatment, and that, alone or in combination, identify those individuals who are likely to respond best to a potential treatment, both in terms of limiting joint damage and relieving symptoms. The aims of this review are to describe currently available biochemical markers of joint metabolism in relation to the pathobiology of joint damage and systemic bone loss in RA; to assess the limitations of, and need for additional, novel biochemical markers in RA and other rheumatic diseases, and the strategies used for assay development; and to examine the feasibility of advancement of personalized health care using biochemical markers to select therapeutic agents to which a patient is most likely to respond.

IL-6 Receptor Inhibition Positively Modulates Bone Balance in Rheumatoid Arthritis Patients with an Inadequate Response to Anti-Tumor Necrosis Factor Therapy: Biochemical Marker Analysis of Bone Metabolism in the Tocilizumab RADIATE Study (NCT00106522)

OBJECTIVE To evaluate changes in biochemical markers of bone metabolism in response to tocilizumab in patients with anti-tumor necrosis factor-refractory rheumatoid arthritis (RA). METHODS RADIATE was a randomized, double-blind, placebo-controlled, parallel-group phase 3 trial. C-reactive protein, osteocalcin (OC), C-terminal telopeptides of type-I collagen (C-terminal telopeptides of type-1 collagen (CTX-I) and type-I collagen degradation product), and matrix metalloproteinase-3 (MMP-3) serum levels were analyzed from 299 RA patients. Patients were randomly assigned to either tocilizumab (4 or 8 mg/kg) or placebo intravenously every 4 weeks, along with concomitant stable methotrexate (10 to 25 mg weekly) in all treatment arms. The change in biochemical markers CTX-I and OC in combination was evaluated as a measure of net bone balance, a reflection of the change in equilibrium between resorption and formation. RESULTS Both tocilizumab doses decreased C-reactive protein levels and significantly inhibited cathepsin K-mediated bone resorption in RADIATE subjects, as measured by a decrease in CTX-I. There was a significant overall improvement in net bone balance at week 16 as measured by a decrease in the CTX-I:OC ratio (-25%, P < 0.01). Furthermore, a significant reduction in MMP-3 (43%, P < 0.001) and type-I collagen degradation product levels (18%, P < 0.001) were observed following treatment, both consistent with decreased MMP-mediated type-I collagen catabolism in joint tissue. CONCLUSIONS In anti-tumor necrosis factor-refractory patients, tocilizumab significantly reduced the levels of biochemical markers of cathepsin K-mediated bone resorption and MMP-mediated tissue degradation and remodeling. These observations suggest that tocilizumab has a positive effect on bone balance, which could in part explain the retardation of progressive structural damage observed with tocilizumab. Clinical trial registry number: NCT00106522.

IL-6 pathway-driven investigation of response to IL-6 receptor inhibition in rheumatoid arthritis

Objectives To determine whether heterogeneity in interleukin-6 (IL-6), IL-6 receptor and other components of the IL-6 signalling pathway/network, at the gene, transcript and protein levels, correlate with disease activity in patients with rheumatoid arthritis (RA) and with clinical response to tocilizumab. Design Biomarker samples and clinical data for five phase 3 trials of tocilizumab were analysed using serum (3751 samples), genotype (927 samples) and transcript (217 samples) analyses. Linear regression was then used to assess the association between these markers and either baseline disease activity or treatment response. Results Higher baseline serum IL-6 levels were significantly associated (p<0.0001) with higher baseline DAS28, erythrocyte sedimentation rate, C reactive protein and Health Assessment Questionnaire in patients whose responses to disease-modifying antirheumatic drugs (DMARD-IR) and to antitumour necrosis factor (aTNF-IR) were inadequate and patients who were naive/responders to methotrexate (MTX). Higher baseline serum IL-6 levels were also significantly associated with better clinical response to tocilizumab (versus placebo) measured by cDAS28 in the pooled DMARD-IR (p<0.0001) and MTX-naive populations (p=0.04). However, the association with treatment response was weak. A threefold difference in baseline IL-6 level corresponded to only a 0.17-unit difference in DAS28 at week 16. IL-6 pathway single nucleotide polymorphisms and RNA levels also were not strongly associated with treatment response. Conclusions Our analyses illustrate that the biological activity of a disease-associated molecular pathway may impact the benefit of a therapy targeting that pathway. However, the variation in pathway activity, as measured in blood, may not be a strong predictor. These data suggest that the major contribution to variability in clinical responsiveness to therapeutics in RA remains unknown.

Genetic variation in UGT1A1 typical of Gilbert syndrome is associated with unconjugated hyperbilirubinemia in patients receiving tocilizumab.

Objective Tocilizumab, a monoclonal antibody to interleukin-6 receptor, was recently approved for the treatment of moderate-to-severe rheumatoid arthritis. Two patients during clinical development met laboratory, but not clinical, criteria for Hys law with bilirubin elevations suspected as a result of genetic variation in uridine diphosphoglucose glucuronosyltransferase (UGT1A1) typical of Gilbert syndrome. Methods Genotyping of the two cases potentially meeting with Hys law was performed using commercially available procedures. UGT1A1 single nucleotide polymorphism data were extracted from a genome-wide array database for 1187 patients from tocilizumab trials, and associations of UGT1A1 genotypes with bilirubin elevations were analyzed using logistic regression for associations with baseline and change from baseline in bilirubin levels as continuous variables. Results Bilirubin elevations were not associated with clinical adverse events. Both patients potentially meeting Hys law carry homozygous UGT1A1*28 alleles and UGT1A1*60 alleles. UGT1A1*28 and three additional single nucleotide polymorphisms showed odds ratios greater than 25 for associations with elevated bilirubin. The presence of rs6742078 accounted for 32% of the total variance in bilirubin (P=2.2×10−53). Conclusion Bilirubin increases occurring with tocilizumab appear to be related to anti-inflammatory effects extending to the liver. Thus, in the absence of other signs of hepatic dysfunction, bilirubin elevations after treatment with tocilizumab have a high probability of association with UGT1A1 polymorphism, which should alleviate concerns of serious hepatotoxicity. Our results underscore the value of genotyping in the clinical trial setting to avoid misinterpretations that could lead to terminating development of a promising new agent.

Serological biomarkers of joint tissue turnover predict tocilizumab response at baseline.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by polyarticular joint inflammation resulting in massive tissue turnover. The turnover is partly mediated by an up-regulation of proteolytic enzymes, such as matrix metalloproteinases (MMPs).1 Matrix metalloproteinase 3 is 1 of the MMPs responsible for the degradation of the extracellular matrix (ECM).2 The MMP-mediated degradation of the main joint ECM proteins (eg, types I and III collagen)3 results in the release of specific biomarkers such as the connective tissue biomarkers C1M and C3M,4,5 known as protein fingerprints. These biomarkers are direct measures of changes to the tissue affected by the disease, in contrast to measurement of acute reactants such as C-reactive protein (CRP) or interleukin 6 (IL-6), which are upstream of tissue changes.6 Thus, protein fingerprint biomarkers may be more sensitive tools for measuring disease changes or changes caused by intervention. Protein fingerprint biomarkers have been associated with disease progression and response to therapy.7,8 CRPM is a protein fingerprint formed through degradation of CRP. In response to IL-6, CRP is secreted by the liver as an acute phase reactant.9 C-reactive proteinaccumulates in inflamed tissue, where it is degraded by MMPs, resulting in the release of CRPM.10 The ratio of C3M to CRPM may depict MMP3 is 1 of the MMPs responsible for the degradation of the ECM; its expression is highly elevated in the affected joint and may therefore be a relevant marker of proteolytic activity.2 Tocilizumab (TCZ) is approved in 2 doses for intravenous infusion:4 and 8 mg/kg. Although both doses provide structural progression and symptomatic relief, 8 mg/kg generally affords a higher level of response.11 Composite quantifiable measures depending on CRP were more reduced in 8 mg/kg compared with 4 mg/kg.12,13 As there are more adverse events in the higher dose,14 identification of those patients who respond most optimally to 4 mg/kg would significantly improve the benefit-to-risk assessment. The aim of present study was to identify responders to 4 mg/kg TCZ by measuring protein fingerprints at baseline.

Rheumatoid Arthritis: A Case for Personalized Health Care?

Ethical, clinical, and economic considerations highlight the pressing need to advance the identification of optimal treatments for each individual patient. Personalized health care (PHC) may provide a significant benefit in the treatment of a number of clinical indications characterized by costly therapy, low response rates, and significant problems associated with trial and error prescription, including the risk of serious side effects. As an example, we focused on the promise of PHC for the field of rheumatology, in particular the use of diagnostic practice in guiding the treatment of rheumatoid arthritis (RA). While RA may seem to be a disease optimally suited for PHC, some stakeholders question the need, possibilities, and benefits of such a practice (1). In this review, we offered a deconstruction of the application of novel predictive diagnostics on the practice of medicine in RA. We outlined the opportunities and current success and lack thereof across the RA field and attempted to outline emerging opportunities that benefit patients, physicians, health care payors, and the pharmaceutical industry in ensuring the right patients are treated with the right drug. The key messages in this review are 1) identification of the right treatment for the right patients will benefit patients, physicians, and payors, 2) PHC may help shape the development of treatments by the pharmaceutical industry, 3) PHC is of particular relevance for indications with low response rates and significant adverse effects (AEs), and 4) novel biomarker technologies may help deliver PHC to RA. Most medicines are currently prescribed stochastically, through trial and error. Recent advances, however, in our understanding of the etiology of underlying disease, drug response, and adverse drug reactions tantalizingly suggest an opportunity to identify patients or groups of patients that are more likely to respond in a safe and effective manner to specific therapies. The well-recognized complexity of drug development is at least in part due to the heterogeneity of the underlying disease observed within any patient population. PHC has often been suggested as a solution to this complexity (2), but the majority of examples of successful PHC are currently drawn from the oncology field and, as such, reflect a relatively simplistic concept of therapeutic stratification based on the targeting of constitutively activated pathways in an oligogenic model of disease. Conversely, reportable successes for PHC in the field of polygenic disease are few and far between. This poses the question as to whether therapeutic areas (TAs) and specific diseases outside the field of oncology can ultimately benefit from a tailored approach to prescription that identifies patients who will receive the greatest benefit from any particular treatment. Most likely, selected TAs may be more suited for PHC than others. These areas would be characterized by highly heterogeneous patient populations, low response rates, and high burden of side effects originating from traditional trial and error prescription and finally a high cost of the given therapy. Several applied examples of the need for PHC are provided by osteoporosis and non–small cell lung carcinoma (NSCLC). With relatively benign side effects and high response rates from established therapies, the need for a stratification of patients in osteoporosis, beyond that offered by projected imaging of bone mineral density (3–5) in the initial assessment of fracture risk, is limited. As such, despite early reports linking the commonly preMorten A. Karsdal, MSc, PhD, mMBA, Anne-Christine Bay-Jensen, MSc, PhD, Kim Henriksen, PhD, Claus Christiansen, MSc, MD: Nordic Bioscience, Herlev, Denmark; Harry K. Genant, MD: CCBR/SYNARC, Newark, California; Chris Chamberlain, MABM, BMBCh, PhD: UCB, Slough, UK; Adam Platt, PhD: AstraZeneca UK Ltd., Cheshire, UK. Dr. Karsdal owns stock or stock options in Nordic Bioscience. Dr. Bay-Jensen has received consultancy fees, speaking fees, and/or honoraria (less than

OP0127 Identification of serological biomarker profiles associated with early response to tocilizumab in rheumatoid arthritis

10,0000) from Biogen and owns stock or stock options in Nordic Bioscience. Dr. Christiansen owns stock or stock options in Nordic Bioscience. Dr. Genant has received consultancy fees, speaking fees, and/or honoraria (less than

Translational Biomarkers and Ex Vivo Models of Joint Tissues as a Tool for Drug Development in Rheumatoid Arthritis

10,000 each) from Amgen, Novartis, and Lilly, and (more than

An analytical comparison between point-of-care uric acid testing meters

10,000) from SYNARC. Dr. Chamberlain owns stock or stock options in Roche, UCB, GlaxoSmithKline, and AstraZeneca, and holds a patent for pharmacogenetic prediction of bisphosphonate response in osteoporosis. Dr. Platt owns stock or stock options in AstraZeneca. Address correspondence to Morten A. Karsdal, MSc, PhD, mMBA, Nordic Bioscience A/S, Herlev Hovedgade 207, DK2730 Herlev, Denmark. E-mail: mk@nordicbioscience.com. Submitted for publication July 25, 2013; accepted in revised form January 14, 2014. Arthritis Care & Research Vol. 66, No. 9, September 2014, pp 1273–1280 DOI 10.1002/acr.22289

THU0232 Serological Biomarkers of Joint Turnover PREDICT Early Responders to TOCILIZUMAB Intervention

Background RA characterized by poly-articular and synovial inflammation, cartilage loss and erosion of subchondral bone. It is critical to diagnose and effectively treat the disease early to suppress inflammation and prevent destruction of the joint. Thus, identification of the patients most likely to respond to a given intervention may be pursued for optimal benefits for both patients and payers. Objectives To investigate early changes in biomarkers of bone, cartilage, synovium and inflammation as an effect of tocilizumab (TCZ) treatment, and to identify profiles associated with responders and non-responders. Methods The LITHE study (Roche WA17823) is a 2-year phase III, 3-arm randomized, double-blind, placebo-controlled, parallel group, with moderate/severe active RA, inadequate response to MTX. 1196 patients were randomized to the 3 treatment groups: TCZ8mg/kg (TCZ8), TCZ4mg/kg or placebo. Every 4 weeks, patients received an infusion of TCZ8 mg/kg or 4mg/kg placebo for a total of up to 13 infusions in 52 weeks. Escape patients was defined as those who experienced <20% improvement in both swollen (SJC) and tender joint counts (TJC) at week 16. These patients were designated non-responders in current sub-study. The sub-study only the TCZ8 group was investigate and fasted serum was analyzed baseline and week 4weeks. Following biomarkers were measured: C2M (cartilage degradation), C3M (synovial inflammation), MMP3, total CRP, CRPM (MMP-degraded CRP), VICM (Citrullinated and MMP degraded Vimentin), ICTP (MMP destroyed type I collagen), osteocalcin (bone formation) and CTX-I (Bone resorption). The sub-study consisted of 102 responders and 33 non-responders. Data is shown as percentage change from baseline (Mann-Whitney test). Results Cartilage degradation - C2M - was reduced to 90.4% of baseline levels upon treatment with TCZ8 in the responder group, whereas the level of C2M was increased to 111% of baseline level in the non-responder group (p=0.0031). Synovial tissue turnover, C3M, was decreased to 77.3% of baseline in the responder group, compared to 90.5% in the non-responder group (p=0.0034). MMP-3, ICTP and Citrullinated vimentin decreased to approx. 85% of baseline and there were no difference between the groups. The general inflammatory marker hsCRP was decreased in both responders and non-responders to approx. 35%, with no significant ability to separate these groups. In contrast, there was a significant difference between the level of MMP cleaved CRP, CRPM (p=0.031). The level of CRPM was decreased to 75.9% in the responder group and only to 85.9% in non-responder group. There were only minimal significant differences in the bone resorption and bone formation markers. Conclusions The novel biomarkers of cartilage and synovial turnover were able to discriminate between responders and non-responders to IL-6 intervention, in contrast to traditional CRP and bone markers. Whether the markers may reflect the same response and power for prediction to other biological interventions need to be investigated. TCZ strongly inhibited cartilage degradation and inflammation mediated tissue turnover which may explain the clinical benefits of this biological intervention. Disclosure of Interest None Declared