Clinical And Experimental Study Of Recombinant Human Tumor Necosis Factor-Fc Fusion Protein (etanercept) In The Treatment Of Ankylosing Spondylitis

Objective:1. To evaluate the efficacy and safety of a recombinant human tumor necrosis factor receptor: Fc fusion protein (etanercept) in ankylosing spondylitis ( AS ) and to investigate the potential parameters which may predict clinical response.2. To investigate the predictors of relapsing after discontinuing the treatment of etanercept in AS.3. To understand the influence of a single dosage etanercept on the disease activity of AS and the duration of efficacy of single dose etanercept.Methods:1. This was a randomized, double-blind, placebo-controlled trial. 52 patients with active AS were randomly assigned to receive twice-weekly subcutaneous injections of etanercept (25 mg) or placebo for 6 weeks. Then both groups were treated with etanercept for another 6 weeks. The primary end point was proportion of ASAS20 (Assessments in Ankylosing Spondylitis 20%) responders. The efficacy and safety were assessed. And the parameters predicting the clinical response to etanercept in AS were analysed with Logistic regression liklihood ratio tests.2. After the trial, the patients who attained an ASAS20 response at week 12 were randomly assigned to receive SSZ (Sulfasalazine), thalidomide or without drugs and they were followed up until disease relapsed. The statistical tools used were the Cox's Proportionate Hazard Model and the logrank method. The data were also used to test if there were any parameters predicting the relapse.3. Twenty patients of active AS were randomly assigned to receive singlesubcutaneous injections of etanercept (25 mg or 50 mg) and were followed up for 20 days. The changes of BASDAI (Bath AS Disease Activity Index) and BASFI (Bath AS Functional Index) were observed and the duration of efficacy were analyzed.Rusults:1. At week 6, 80% of patients in the etanercept group reached the primary end point of ASAS20, compared with 31% of patients receiving placebo (p<0.0\). The percent of patients achieving the secondary end points of ASAS50, ASAS70 and BASDAI50 were 58% (p<0.01), 31% (p<0.01) and 62% (p< 0.01) in the etanercept group and 4%, 0% and 15% in the placebo group respectively. Improvements over base-line values for various measures, including BASDAI, BASFI, PGA (Patient's Global Assessment), spine pain, moring stiffness, score for peripheral-joint tenderness, swollen-joint score, El (Enthesis Index) and ESR/CRP, were significantly greater in the etanercept group. BASMI was an exception.2. There were no serious adverse reactions observed. The most frequently treatment related adverse event was injection site reaction (34.6%). Six patients (23.1%) in the etanercept group developed transient reduction of neutrophil during the double-blined period. There were no significant differences in infection and other adverse reactions between both groups.3. Logistic regression analysis showed shorter disease duration, high BASDAI score and swollen-joint score at baseline predicted ASAS50 response and younger, high spine inflammation score or CRP levels and low swollen-joint score predicted ASAS70 response in patients with AS treated with etanercept.4. Those patients who attained an improvement of ASAS20 at week 12 were followed up. The percent of patients who relapsed in the SSZ group, thalidomide group and no treatment group were 76.9%, 43.8% and 75% respectively. There were no significant differences compared with each other (p >0.05). Twenty-nine patients (64.4%) relapsed and the mean time was 3.2±2.2months. High PGA and spine inflammation score, high CRP level and low swollen-joint score at baseline were the predictors of relapse.5. Twenty patients received a single subcutaneous injections of etanercept (25 mg or 50 mg). Only after one day the BASDAI scores were less 36% in the 25 mg etanercept group and 45% in the 50mg etanercept group compared with basline (p<0.0\), and there was no significant difference between both groups(/? =0.83). Four patients of the 25 mg group and 7 patients of the 50 mg group achieved BASDAI50 response (p=0.3687). To those patients who achieved response, the mean time maintenance with BASDAI < 4 was (14.5±6.1) days in 25 mg group and (13.8±6.3) days in 50 mg group.Conclusion:1. Treatment with etanercept resulted in rapid, significant and sustained improvement in patients with AS.2. Etanercept was safe and well tolerated. It was not associated with an increase the rate of infection. The most frequently adverse event was injection site reaction.3. Younger age, shorter disease duration and higher disease activity was related to a higher likelihood to response.4. There seems to be a trend that thalidomide was helpful to prevent the relapse after discontinued the treatment of etanercept. High PGA and spine inflammation score or CRP level and low swollen-joint score at baseline seem to be the predictors of disease relapse.5. A single dosage etanercept treatment resulted in rapid improvement in some patients with AS. The therapeutic effect could last about 2 weeks.Objective:To assess the changes in the cytokine secreting ability of CD4~+and CD8~+T cells and in the serum level of matrix metalloproteinase 3 during etanercept treatment in AS.Methods:1. Peripheral blood from 15 patients with AS treated with 25 mg etanercept and 15 patients with AS treated with placebo were investigated at week 0, week 6 and week 12 during a randomized, double-blind, placebo-controlled trial. Intracellular cytokine staining and three-color flow cytometric analysis were used to investigate intracellular cytokines (TNF-a, IFN-γand IL-4) and surface antigens (CD3, CD8) of T cell in the peripheral blood of AS patients.2. MMP-3 in serum samples of 26 patients with AS were measured by ELISA at week 0, 1, 2,4, 8, 12 during etanercept treatment (25 mg, twice a week). The change of MMP-3 between before and after treatment and the correlation with the clinical parameters including ESR, CRP, BASDAI and BASFI was analyzed.Rusults:1 .The positive rates of IFN-γ-producing cells among either CD4~+ or CD8~+ T cells were significantly higher than those of IL-4-producing cells in the peripheral blood of patients with AS(p<0.01). Twelve weeks of etanercept treatment induced a significant increase in the number of IFN-γ and TNF-a positive CD4~+ T cell (p<0.001) and CD8~+ T cell(p<0.05). At week 6, there was no change in the placebo. But at week 12, a significant increase in the number of IFN-γpositiveCD8+ T celK P<0.05 )was observed. In both the etanercept and the placebo group, no significant changes of IL-4 secretion were seen during treatment.2.. Significant correlations were observed between serum levels of MMP-3 and ESR (r=0.74, p <0.0001) and CRP (r=0.72,p O.0001) in patients with active AS at week 0. There was significant reduction in MMP-3 after 1 week of etanercept treatment (p<0.0001) and to the minimum at week 12. The trend was coincidence with those of ESR, CRP, BASDAI and BASFI. The serum level of MMP-3 had significant correlation with ESR (r=0.43, p=0.029) at week 12. Conclusion:1. The treatment with etanercept in AS induced an up-regulation of the ability of T cells to produce TNF-a and IFN-y.2. The treatment with etanercept in active AS induced a reduction of the serum level of MMP-3, and it could be used to monitor the response to etanercept.