John T Sharp

University of Washington Seattle, Seattle, Washington, United States

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Publications (43)221.23 Total impact

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    ABSTRACT: Osteoclast-mediated bone loss in the hand predicts future bone erosions in patients with rheumatoid arthritis (RA). Osteoclast activity depends on RANKL, which is inhibited by denosumab, an investigational fully human monoclonal antibody against RANKL. We measured metacarpal shaft cortical bone thickness using a novel computer-based technique, digital x-ray radiogrammetry (DXR), to evaluate the effects of denosumab on cortical bone in RA. Patients (n = 227) with active, erosive RA were randomized to receive subcutaneous denosumab 60 mg or 180 mg or placebo every 6 months. All patients received stable doses of methotrexate and daily calcium and vitamin D. For this blinded post hoc analysis (n = 218), cortical bone loss was determined by DXR using computer-assisted measurement of cortical thickness and shaft width at 21 midshaft levels of the second through fourth metacarpal bones of both hands. At 12 months, patients receiving denosumab had significantly less metacarpal bone loss versus placebo (denosumab 60 mg: -0.0034, denosumab 180 mg: 0.0001 gain, placebo: -0.0108; P < or = 0.01 for both denosumab doses). Twelve-month decreases from baseline greater than the smallest detectable change occurred in 2 patients in the denosumab 180 mg group, 9 patients in the denosumab 60 mg group, and 12 patients in the placebo group. Negative correlation was significant between static cortical thickness ratios and static erosion scores (6 and 12 months), and for placebo, between changes in erosion scores and changes in cortical thickness ratio. Twice-yearly injections of denosumab with ongoing methotrexate treatment significantly reduced cortical bone loss in RA patients for up to 12 months. These results add to the growing evidence supporting the clinical utility of DXR.
    Arthritis care & research. 04/2010; 62(4):537-44.
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    ABSTRACT: To evaluate responses by time to initiation of nonbiologic disease-modifying antirheumatic drugs (DMARD) in a DMARD-naive cohort of patients with early seropositive rheumatoid arthritis (RA). Subjects were categorized by the time from symptom onset to the first DMARD use (median 5.7 months, range 0.6-15.9). Subjects who started their first DMARD within 5 months of symptom onset were compared to subjects who started after 5 months. Disease Activity Scores (DAS-44) and total Sharp Score (TSS) progression rates were analyzed using Wilcoxon rank-sum and chi-square tests; multiple linear regression analysis adjusted for potential covariates. The slope of the least-squares regression line was calculated to estimate the annualized TSS progression rates. Of 233 RA patients, 76% were female and mean age was 50 (SD 13) years. At DMARD start, DAS-44 was similar in all subsets within the 0.6 to 15 months' duration between symptom onset and DMARD initiation. Erosion scores tended to be higher in those who started DMARD later, but Health Assessment Questionnaire-Disability Index (HAQ-DI) scores were higher in those who started DMARD earlier. During the 2 years after DMARD initiation, improvements in HAQ-DI and DAS-44 were similar in the various duration subsets, with about 25% ever achieving DAS remission (DAS < 1.6). Radiographic progression tended to be numerically but not statistically more rapid in the earlier subsets. Following initiation of nonbiologic DMARD therapy at various times within 15 months of symptom onset, improvements of DAS-44, HAQ-DI, remission rate, and radiographic progression rate were similar, although higher baseline erosion scores were present in those with later initiation of DMARD.
    The Journal of Rheumatology 03/2010; 37(3):550-7. · 3.26 Impact Factor
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    ABSTRACT: Previously reported data on 5 computer-based programs for measurement of joint space width focusing on discriminating ability and reproducibility are updated, showing new data. Four of 5 different programs for measuring joint space width were more discriminating than observer scoring for change in narrowing in the 12 months interval. Three of 4 programs were more discriminating than observer scoring for the 0-18 month interval. The program that failed to discriminate in the 0-12 month interval was not the same program that failed in the 0-18 month interval. The committee agreed at an interim meeting in November 2007 that an important goal for computer-based measurement programs is a 90% success rate in making measurements of joint pairs in followup studies. This means that the same joint must be measured in images of both timepoints in order to assess change over time in serial radiographs. None of the programs met this 90% threshold, but 3 programs achieved 85%-90% success rate. Intraclass correlation coefficients for assessing change in joint space width in individual joints were 0.98 or 0.99 for 4 programs. The smallest detectable change was < 0.2 mm for 4 of the 5 programs, representing 29%-36% of the change within the 99th percentile of measurements.
    The Journal of Rheumatology 09/2009; 36(8):1825-8. · 3.26 Impact Factor
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    ABSTRACT: To determine the relationship between radiographic progression and clinical response for adalimumab plus methotrexate (MTX) versus either monotherapy in patients with early rheumatoid arthritis (RA) in the PREMIER study. Patients with early RA who received adalimumab plus MTX (n = 240), adalimumab (n = 222), or MTX (n = 216) were grouped by American College of Rheumatology (ACR) response, 28-joint Disease Activity Score (DAS28), or remission-like state [tender joint count (TJC) = 0; DAS28 < 2.6; swollen joint count = 0; ACR100] at 26 and 104 weeks. Radiographic progression was assessed by cumulative probability plots, mean changes in total Sharp score (DeltaTSS), and percentages of progressors (DeltaTSS > 0.5). Across the spectrum of clinical outcomes, including ACR20 nonresponses and remission-like responses, therapy with adalimumab plus MTX permitted less radiographic progression at Weeks 26 and 104 than MTX monotherapy. Adalimumab monotherapy was generally intermediate. A strong, proportional relationship was observed between clinical response and radiographic efficacy only for MTX monotherapy. The monotherapies approximated the radiographic efficacy of adalimumab plus MTX only among remission-like responders, although progression was significantly greater with MTX monotherapy versus adalimumab plus MTX for patients with TJC = 0. Concurrent clinical (DAS28 < 2.6) and radiographic (DeltaTSS <or= 0.5) remission was significantly more frequent at Week 104 with adalimumab plus MTX (45%) than with adalimumab (25%) or MTX (18%) monotherapy. In patients with early RA, adalimumab plus MTX resulted in less radiographic progression than MTX monotherapy across the spectrum of clinical response, including ACR20 non-responses and remission-like responses.
    The Journal of Rheumatology 04/2009; 36(7):1429-41. · 3.26 Impact Factor
  • John T Sharp
    The Journal of Rheumatology 12/2008; 35(11):2090-3. · 3.26 Impact Factor
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    ABSTRACT: To evaluate the long-term effectiveness and tolerability of adalimumab in the treatment of psoriatic arthritis (PsA). Patients with PsA who completed a 24-week, double-blind study of adalimumab versus placebo were eligible to enroll in an open-label extension study and receive adalimumab 40 mg subcutaneously every other week for up to an additional 120 weeks. At the time of this analysis, available efficacy evaluations throughout 2 years of treatment (n = 245) included American College of Rheumatology (ACR) 20%, 50% and 70% improvement scores, measures of joint disease and skin disease, disability and quality of life; modified total Sharp scores (mTSS) were available for 2.75 years of treatment for patients who received adalimumab in the 24-week study. After 24 weeks of double-blind treatment, the mean change in mTSS was -0.2 for the adalimumab group (N = 144) and 1.0 for the placebo group (N = 152; p<0.001), and outcomes for all individual ACR component variables were significantly improved in adalimumab compared with placebo-treated patients. Compared with 24-week responses, inhibition of radiographic progression and improvements in joint disease were maintained in most patients during long-term, open-label adalimumab treatment. Also, improvements in skin disease were maintained, with >20% of patients achieving the strict criterion of psoriasis area and severity index 100. The nature and frequency of adverse events during long-term adalimumab treatment were consistent with the safety profile during short-term treatment. The clinical and radiographic efficacy of adalimumab demonstrated during short-term treatment was sustained during long-term treatment. Adalimumab has a favourable risk-benefit profile in patients with PsA. Trial registration number: NCT00195689.
    Annals of the rheumatic diseases 08/2008; 68(5):702-9. · 8.11 Impact Factor
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    ABSTRACT: Comparison of performances of 5 (semi)automated methods in measuring joint space width (JSW) in rheumatoid arthritis. Change in JSW was determined by 5 measurement methods on 4 radiographs per patient from 107 patients included in the COBRA trial (comparing sulfasalazine alone or in combination with methotrexate and corticosteroids). For each method the number of patients with sufficient available results was assessed (efficiency). An independent repeated measurement was carried out on a random sample of 30 patients' baseline and 1-year radiographs, to evaluate within-method reliability of change scores. Discriminatory ability (DA) of the measurement methods (between the 2 treatment arms) was compared with the DA of the Sharp-van der Heijde score (SHS) and its 2 components (erosion and JSW scores). The overall success rate varied widely between methods. Applying the chosen threshold of a minimum of 50% available joints with a change score per patient resulted in a success rate > 92% in 4/5 methods. Repeatability of measurements was good for most methods (intraclass correlation coefficient > or = 0.80 in 4/5 methods). Almost all measurement methods in 3 followup periods (12/14) showed a lower mean loss of JSW in patients from the intensive treatment group, although this was rarely statistically significant, confirming the known difference in structural damage. JSW as measured by the (semi)automated systems often showed higher DA than the JSW score of the SHS, but was lower than the total SHS and erosion scores. Although efficiency of the methods should be improved further, results already show good reliability and encouraging DA of most methods. Optimal information may be obtained with a combination of scoring of erosions and (semi)automated measurement of JSW.
    The Journal of Rheumatology 07/2008; 35(7):1288-93. · 3.26 Impact Factor
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    ABSTRACT: RANKL is essential for osteoclast development, activation, and survival. Denosumab is a fully human monoclonal IgG2 antibody that binds RANKL, inhibiting its activity. The aim of this multicenter, randomized, double-blind, placebo-controlled, phase II study was to evaluate the effects of denosumab on structural damage in patients with rheumatoid arthritis (RA) receiving methotrexate treatment. RA patients received subcutaneous placebo (n = 75), denosumab 60 mg (n = 71), or denosumab 180 mg (n = 72) injections every 6 months for 12 months. The primary end point was the change from baseline in the magnetic resonance imaging (MRI) erosion score at 6 months. At 6 months, the increase in the MRI erosion score from baseline was lower in the 60-mg denosumab group (mean change 0.13; P = 0.118) and significantly lower in the 180-mg denosumab group (mean change 0.06; P = 0.007) than in the placebo group (mean change 1.75). A significant difference in the modified Sharp erosion score was observed as early as 6 months in the 180-mg denosumab group (P = 0.019) as compared with placebo, and at 12 months, both the 60-mg (P = 0.012) and the 180-mg (P = 0.007) denosumab groups were significantly different from the placebo group. Denosumab caused sustained suppression of markers of bone turnover. There was no evidence of an effect of denosumab on joint space narrowing or on measures of RA disease activity. Rates of adverse events were comparable between the denosumab and placebo groups. Addition of twice-yearly injections of denosumab to ongoing methotrexate treatment inhibited structural damage in patients with RA for up to 12 months, with no increase in the rates of adverse events as compared with placebo.
    Arthritis & Rheumatology 06/2008; 58(5):1299-309. · 7.48 Impact Factor
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    ABSTRACT: To evaluate concordance and agreement of the original DAS44/ESR-4 item composite disease activity status measure with nine simpler derivatives when classifying patient responses by European League of Associations for Rheumatology (EULAR) criteria, using an early rheumatoid factor positive (RF+) rheumatoid arthritis (RA) patient cohort. Disease-modifying anti-rheumatic drug-naïve RF+ patients (n = 223; mean duration of symptoms, 6 months) were categorised as ACR none/20/50/70 responders. One-way analysis of variance and two-sample t tests were used to investigate the relationship between the ACR response groups and each composite measure. EULAR reached/change cut-point scores were calculated for each composite measure. EULAR (good/moderate/none) responses for each composite measure and the degree of agreement with the DAS44/ESR-4 item were calculated for 203 patients. Patients were mostly female (78%) with moderate to high disease activity. A centile-based nomogram compared equivalent composite measure scores. Changes from baseline in the composite measures in patients with ACRnone were significantly less than those of ACR20/50/70 responders, and those for ACR50 were significantly different from those for ACR70. EULAR reached/change cut-point scores for our cohort were similar to published cut-points. When compared with the DAS44/ESR-4 item, EULAR (good/moderate/none) percentage agreements were 92 with the DAS44/ESR-3 item, 74 with the Clinical Disease Activity Index, and 80 with the DAS28/ESR-4 item, the DAS28/CRP-4 item and the Simplified Disease Activity Index. The relationships of nine different RA composite measures against the DAS44/ESR-4 item when applied to a cohort of seropositive patients with early RA are described. Each of these simplified status and response measures could be useful in assessing patients with RA, but the specific measure selected should be pre-specified and described for each study.
    Annals of the rheumatic diseases 01/2008; 66(12):1633-40. · 8.11 Impact Factor
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    ABSTRACT: In recent years, development of rheumatoid arthritis (RA) drug therapy has been more directly targeted to counteract specific mechanisms of inflammation, and it is now believed that early aggressive treatment with disease modifying drugs is important to inhibit future structural joint damage. The development of these new treatments has increased the need for methodologies to assess disease activity in RA and monitor the effectiveness of drug therapy. Unlike X-ray, which shows only structural bone damage, magnetic resonance imaging (MRI) can depict soft tissue damage and synovitis, the primary pathology of RA. Recent studies have also indicated that MRI is sensitive to pathophysiologic changes that may predate radiographic erosions and may predict future joint damage. In this study, we have developed a computer automated analysis technique for MR wrist images that provides an objective measure of RA synovitis. This method applies a two-compartment pharmacokinetic model to every voxel of a dynamic contrast-enhanced MRI (DCE-MRI) dataset and outputs resulting parametric images. The aim of this technique is to not only objectively quantify the severity of rheumatoid synovitis, but to also locally determine where areas of serious disease activity are situated through kinetic modeling of blood-tissue exchange. Preliminary results show good correlation to early enhancement rate, which has previously been shown to be a useful clinical marker of RA activity. However, the use of tracer kinetic modeling methods potentially provides more specific information regarding underlying RA physiology. This approach could provide a useful new tool in RA patient management and could substantially improve RA therapeutic studies by calculating objective biomarkers of the disease state.
    Annals of Biomedical Engineering 06/2007; 35(5):781-95.
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    ABSTRACT: Computer-based methods of measuring joint space width (JSW) could potentially have advantages over scoring joint space narrowing, with regard to increased standardization, sensitivity, and reproducibility. In an early exercise, 4 different methods showed good agreement on measured change in JSW over time in the small joints of the hands and feet. Despite differences in measurement values between methods, measurement of within-joint change over time showed no systematic differences. The within-method variation was small, with intra-operator variation being smaller than inter-operator variation. Although this initial study was limited in terms of the number of patients and timepoints (total 10), the number of joints was relatively high (340 joints), so the results were considered strong evidence supporting the validity of computer-based JSW measurements to continue the study of the potential value of JSW by comparison of measurements to manual scoring of joint space narrowing using the COBRA trial images.
    The Journal of Rheumatology 05/2007; 34(4):874-83. · 3.26 Impact Factor
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    ABSTRACT: Repair of structural damage in rheumatoid arthritis has drawn much attention with newly available effective treatments. A workshop was held at OMERACT 8 to update current knowledge on the validity of the concept of repair and on the assessment of repair. In preparation for the workshop several studies were performed and the results were presented. This was followed by a discussion and voting on statements on various aspects of repair. A majority of participants agreed that results of the new studies strengthen the validity of the concept of repair, and that repair can be assessed on radiographs. There was less agreement on the best means of measurement and there was a plea for more extensive reporting of data, i.e., not limited to sum scores of all joints together. The conclusions of the workshop mean a big step forward in the acceptance and assessment of repair.
    The Journal of Rheumatology 05/2007; 34(4):884-8. · 3.26 Impact Factor
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    ABSTRACT: To evaluate published proposed definitions of minimal disease activity (MDA) and remission in patients with early rheumatoid arthritis (RA). The cohort comprised disease-modifying antirheumatic drug (DMARD)-naive patients with early seropositive active RA (n = 200) treated with traditional DMARDs in the prebiologic era. MDA definitions included Disease Activity Score in 28 joints (DAS28) <or=2.85, or achieving 5 of 7 World Health Organization (WHO)/International League of Associations for Rheumatology (ILAR) core set measure thresholds as proposed by the Outcome Measures in Rheumatology Clinical Trials. Other MDA definitions included Simplified Disease Activity Index (SDAI) score <or=11 and Clinical Disease Activity Index (CDAI) score <or=10. Remission definitions included American College of Rheumatology (ACR) remission, DAS28 <2.6, DAS28 <2.4, achieving all 7 WHO/ILAR core set measure thresholds, SDAI <or=3.3, and CDAI <or=2.8. Physical function was assessed using the Health Assessment Questionnaire (HAQ) disability index (DI) and radiographic progression was assessed using the Sharp score. At baseline, no patients were in MDA or remission. Depending on the MDA definition, 20-32%, 27-32%, and 30-48% were in MDA at 6, 12, and 24 months, respectively. Depending on the remission definition, 0.7-15%, 0-24%, and 0-33% were in remission at 6, 12, and 24 months, respectively. For example, at 6 months, lowest (highest) responses for MDA were seen with DAS28 <or=2.85 (SDAI <or=11) and for remission with ACR remission criteria (DAS28 <2.6). Patients who achieved either MDA or remission had lower HAQ DI and radiographic scores compared with patients who achieved neither. Our study demonstrated that different proportions of patients were classified as MDA or remission depending on the definition used. This has implications in predefining MDA or remission for a clinical trial or to establish goals for optimum management of RA in clinical practice.
    Arthritis & Rheumatology 04/2007; 57(3):440-7. · 7.48 Impact Factor
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    ABSTRACT: The objective of the present study was to test the hypothesis that experts recognize repair of erosions and, if so, to determine which, if any, morphologic features permitted them to recognize the repair. We also tested whether scoring by a standard method detected repair. Seven experienced readers of radiographs in rheumatoid arthritis were presented with 64 sets of single joints-of-interest at two time points, randomized and blinded for the correct sequence. The readers assessed which joint was better, and recorded whether any of six specific features were seen. Two independent readers, experienced in scoring by the van der Heijde-modified Sharp method who were not on the expert panel, then scored the complete films that included the joint-of-interest. The panel agreed very well on which of two joints was better, and, even though they did not know the true sequence, the panel accurately assigned a sequence slightly better than chance alone (58%) but worse than their agreement on which image was 'better or worse' (78%). The readers therefore indirectly assigned repair by choosing the second film as the best. Putative repair features were seen in cases of both repair and progression, and were not discriminatory. Similar results were obtained when the experts were presented with the entire hand or foot containing the joint-of-interest. In the third repair exercise, two independent readers who scored whole hands and feet using a standard method found a mean negative score in 22/60 joints-of-interest. All 22 joints were also scored as repair by the panel. Repair was detected reliably by a majority of the panel on viewing paired images based on a better/worse decision and assigning sequence in a set of images that were blinded for sequence by an independent project manager. In this test set of images, repair was manifested by a reduction in the size of erosion in many cases. Size was one feature that aided the experts to detect repair but cannot be the only one; the experts had to find other features to determine whether a smaller erosion was the first in a sequence of radiographs in a patient with progressive damage or was the second film in a patient exhibiting repair. The change in size of erosion was also picked up by independent readers applying the van der Heijde-modified Sharp scoring method and was reflected in their scores.
    Arthritis research & therapy 02/2007; 9(4):R62. · 4.27 Impact Factor
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    ABSTRACT: To evaluate the efficacy and safety of treatment with adalimumab, a fully human anti-tumor necrosis factor (anti-TNF) monoclonal antibody, over 48 weeks in patients with moderate to severe psoriatic arthritis (PsA). Patients who completed the Adalimumab Effectiveness in Psoriatic Arthritis Trial (ADEPT), a 24-week, double-blind study of adalimumab versus placebo in PsA, could elect to receive open-label adalimumab, 40 mg subcutaneously every other week after week 24. Radiographs were obtained at week 48 and were read with radiographs obtained previously. Clinical and radiographic efficacy data were analyzed overall and in patient subsets. Safety data were collected over 48 weeks. At week 48, patients from the adalimumab arm of ADEPT (n = 151) had achieved American College of Rheumatology 20% improvement (ACR20), ACR50, and ACR70 response rates of 56%, 44%, and 30%, respectively. Among those evaluated with the Psoriasis Area and Severity Index (PASI) (n = 69), PASI50, PASI75, PASI90, and PASI100 response rates (> or =50%, > or =75%, > or =90%, and 100% reduction in PASI scores, respectively) were 67%, 58%, 46%, and 33%, respectively (ACR and PASI response rates were analyzed using nonresponder imputation). Improvements in disability, as measured by the Disability Index of the Health Assessment Questionnaire (mean change in score -0.4) were sustained from week 24 to week 48. At week 24 and week 48, the mean changes from baseline in the modified total Sharp score were -0.1 and 0.1, respectively, for patients who received adalimumab for 48 weeks (n = 133), and 0.9 and 1.0, respectively, for patients who received placebo for 24 weeks followed by adalimumab for 24 weeks (n = 141). Adalimumab demonstrated clinical and radiographic efficacy regardless of whether patients were receiving methotrexate (MTX) at baseline. Adalimumab was generally safe and well tolerated through week 48. Adalimumab improved joint and skin manifestations, reduced disability, and inhibited radiographic progression over 48 weeks in patients with PsA who were participants in ADEPT. MTX use at baseline was not required for clinical or radiographic efficacy. Adalimumab had a good safety profile through week 48.
    Arthritis & Rheumatology 02/2007; 56(2):476-88. · 7.48 Impact Factor
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    ABSTRACT: Various methods are used to measure radiographic joint damage in patients with rheumatoid arthritis (RA), but determining proportions of responsive patients is difficult. A key problem in observational studies when assessing damage outcomes is incorporating time to treatment initialization and adjusting for observed baseline differences. We examined five different definitions to select an appropriate index to classify radiographic damage in RA patients as progressive or nonprogressive. In addition, we compared different times from symptom onset to treatment and their effects on patient radiographic categorization. Propensity scores to adjust for baseline differences, including time since symptom onset, were used to match those treated early with those treated later using the stratification, radius, nearest neighbor and kernel methods. The mean effect of treatment on the treated was computed for each matching method. Observational data were analyzed for 185 early RA patients from the Western Consortium study followed six to sixty months (mean thirty-one months). For the selected index, 75 patients were categorized as nonprogressors; they had significantly lower disease activity, more clinical improvement and were treated earlier than the progressors. Of those treated within three months of symptom onset, 57% were classified as radiographically progressive versus 35% of those treated later (P = 0.0058). However, after propensity score adjustment for baseline differences, we noticed nonsignificant (P > 0.05) nonprogression in patients given earlier treatment. We conclude that propensity score analysis reduced but did not remove all bias.
    Statistical Methods in Medical Research 02/2007; 16(1):13-29. · 2.36 Impact Factor
  • John T Sharp
    The Journal of Rheumatology 11/2006; 33(10):1925-7. · 3.26 Impact Factor
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    ABSTRACT: Clinical and radiographic responses were evaluated in patients with psoriatic arthritis (PsA) treated for up to 2 years with etanercept. Patients were previously randomized to receive placebo or etanercept in a double-blind study and chose to participate in the current open-label extension phase. All patients received etanercept 25 mg twice weekly. Radiographic progression was determined at baseline, 1 year, and 2 years using the Sharp method modified to include joints frequently affected in PsA. Arthritis and psoriasis responses were determined using American College of Rheumatology 20% (ACR20) improvement criteria, PsA response criteria (PsARC), and the psoriasis area severity index (PASI). Of 205 patients randomized, 169 entered open-label, and 141 [71 randomized to receive placebo (placebo/etanercept) and 70 randomized to receive etanercept (etanercept/etanercept)] had radiographic data available for analysis at 2 years. ACR20 criteria, PsARC, and PASI 50 criteria were met by 64%, 84%, and 62%, respectively, of etanercept/etanercept patients at the end of the 48-week open-label period. Placebo/etanercept patients achieved comparable results within 12 weeks that were sustained at 48 weeks (63%, 80%, and 73%). Radiographic progression was inhibited in the etanercept/ etanercept patients (mean adjusted change in total Sharp score of -0.38 from baseline to 2 yrs). In placebo/etanercept patients, disease progression was inhibited once patients began receiving etanercept (mean adjusted change of -0.22 from 1 year to 2 years). Adverse event rates were similar to those observed during randomized phase, with only one serious adverse event deemed possibly related to etanercept. These data demonstrate a sustained benefit of etanercept treatment, including inhibition of radiographic progression, in patients with PsA.
    The Journal of Rheumatology 05/2006; 33(4):712-21. · 3.26 Impact Factor
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    ABSTRACT: To determine whether the tumor necrosis factor alpha (TNFA) -308 guanine-to-adenosine polymorphism and/or the shared epitope (SE) is associated with radiographic damage in patients with early rheumatoid arthritis (RA). The cohort consisted of 189 patients with early seropositive RA (median 5.6 months since symptom onset) who had active disease, no previous disease-modifying antirheumatic drug treatment, and >or=2 sets of scored radiographs of the hands/wrists and forefeet. TNFA -308 polymorphism was analyzed by polymerase chain reaction pyrosequencing. The SE was defined as presence of any 1 of the following HLA-DRB1 alleles: *0101, *0102, *0401, *0404, *0405, *0408, *0410, *1001, *1402, or *1406. Radiographic progression was assessed by the total Sharp score. Using a weighted least-squares regression analysis, patients with the -308 TNFA AA plus AG genotypes (n=49) had significantly higher rates of progression in erosion scores (median 0.84 versus 0.48 units/year), joint space narrowing (JSN) scores (0.42 versus 0.04), and total Sharp scores (1.70 versus 0.61) compared with patients with the TNFA GG genotype (n=140). Presence of the SE (n=137) was associated with significantly lower progression rates (per year) for total Sharp scores (median 0.9 versus 1.25 units/year) and JSN scores (0.04 versus 0.41), but not for erosion scores (0.50 versus 0.61) compared with patients without the SE (n=52). In a least-squares multiple linear regression model, the presence of the AA plus AG genotypes was associated with a significantly higher progression rate after adjusting for the presence of the SE, interaction between the SE and the AA plus AG genotypes, baseline log C-reactive protein level, Health Assessment Questionnaire Disability Index, total Sharp score, swollen joint count, and presence of osteophytes (osteoarthritis). There was a strong linkage disequilibrium between DRB1*0301 and TNFA polymorphism (D'=0.84, r2=0.45, P<0.001). This study showed an association between the TNFA -308 polymorphism and progression of radiographic damage in patients with early seropositive RA. This association appeared to be independent of the SE, but might be dependent on other genetic variants in linkage disequilibrium with the -308 TNFA A allele and DRB1*0301. Further studies should be conducted to validate these results in both longitudinal observational cohorts and randomized clinical trials.
    Arthritis & Rheumatology 05/2006; 54(4):1105-16. · 7.48 Impact Factor
  • John T Sharp
    Nature Clinical Practice Rheumatology 01/2006; 1(2):64-5. · 5.85 Impact Factor

Publication Stats

3k Citations
221.23 Total Impact Points

Institutions

  • 2001–2010
    • University of Washington Seattle
      • • Division of Rheumatology
      • • Department of Medicine
      Seattle, Washington, United States
  • 2003–2009
    • Maastricht University
      • Interne Geneeskunde
      Maastricht, Provincie Limburg, Netherlands
    • Stanford University
      Palo Alto, California, United States
  • 2005–2008
    • University of California, Los Angeles
      • • Department of Medicine
      • • Department of Biostatistics
      • • Division of Rheumatology
      Los Angeles, CA, United States
  • 2007
    • Leiden University Medical Centre
      • Department of Rheumatology
      Leiden, South Holland, Netherlands
    • University of Cincinnati
      Cincinnati, Ohio, United States