Efficacy and safety of bucillamine,a d-penicillamine analogue,in patients with active rheumatoid arthritis

Abstract

Japanese rheumatologists consider bucillamine (Buc) to be a useful disease-modifying antirheumatic drug (DMARD) and often give Buc to patients with rheumatoid arthritis (RA) prior to administering methotrexate (MTX). However, no large studies on the efficacy and safety of Buc in RA patients have been published in English to date. We therefore investigated the clinical course of RA patients treated with Buc and compared the results with those for patients treated with MTX to evaluate and confirm the place of Buc in therapeutic strategies for RA in Japan. Our results suggested that Buc should be given to patients with moderately active RA either before or after the administration of MTX because its efficacy can be judged within 3 months and because serious adverse events are rare. Issues like the ability of Buc to prevent joint destruction and its efficacy and safety when combined with agents like etanercept require future study.     

A comparative study of the effects of bucillamine and salazosulfapyridine in the treatment of rheumatoid arthritis

Bucillamine (Buc), developed in Japan, is a disease-modifying antirheumatic drug (DMARD) which has been used to treat numerous patients with rheumatoid arthritis (RA) in Japan and Korea with favorable results. However, it has not been used globally. In the present study, we compared the timing of onset of efficacy and the usefulness of this drug with that of the globally accepted agent salazosulfapyridine (SASP). There were 26 patients in the Buc group and 23 in the SASP group. We compared changes in the number of swollen joints, number of painful joints, duration of morning stiffness, grip strength, levels of inflammatory marker [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)], rheumatoid factor (RF), physician’s rating by visual analogue scale (VAS), patient’s rating of pain, patient’s overall rating (VAS), and improvement according to European League against Rheumatism (EULAR) criteria (DAS28-CRP, DAS28-ESR) in these two groups of patients. Both Buc and SASP were shown to be efficacious within 3 months after the start of treatment. Both drugs were found to be suitable as first-line treatment of early RA. Signs of efficacy tended to occur earlier with Buc than with SASP, and Buc also tended to have higher efficacy than SASP.     

A comparative study of the effects of bucillamine and salazosulfapyridine in the treatment of rheumatoid arthritis

Abstract

Bucillamine (Buc), developed in Japan, is a disease-modifying antirheumatic drug (DMARD) which has been used to treat numerous patients with rheumatoid arthritis (RA) in Japan and Korea with favorable results. However, it has not been used globally. In the present study, we compared the timing of onset of efficacy and the usefulness of this drug with that of the globally accepted agent salazosulfapyridine (SASP). There were 26 patients in the Buc group and 23 in the SASP group. We compared changes in the number of swollen joints, number of painful joints, duration of morning stiffness, grip strength, levels of inflammatory marker [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)], rheumatoid factor (RF), physician’s rating by visual analogue scale (VAS), patient’s rating of pain, patient’s overall rating (VAS), and improvement according to European League against Rheumatism (EULAR) criteria (DAS28-CRP, DAS28-ESR) in these two groups of patients. Both Buc and SASP were shown to be efficacious within 3 months after the start of treatment. Both drugs were found to be suitable as first-line treatment of early RA. Signs of efficacy tended to occur earlier with Buc than with SASP, and Buc also tended to have higher efficacy than SASP.     

Efficacy profile of bucillamine in rheumatoid arthritis patients in a large observational cohort study, IORRA

Bucillamine (Buc) is a disease-modifying antirheumatic drug (DMARD) developed in Japan, which has been used as one of the first-line DMARDs for the treatment of rheumatoid arthritis (RA) in Japan. However, direct comparison of this drug with standard DMARDs including sulfasalazine (SASP) and methotrexate (MTX) has been scarcely reported. We therefore tried to evaluate the clinical efficacy of Buc by analyzing the database from the long-term observational cohort study IORRA (previously known as J-ARAMIS). The cross-sectional analysis revealed that responses to Buc treatment were better in males, patients with shorter duration of illness, and those who were rheumatoid factor-negative. In the longitudinal analysis, although there was no marked difference among the baseline variables of patients with Buc, SASP, and MTX, the percentage of patients exhibiting moderate or good response to treatment, as rated using the European League Against Rheumatism improvement criteria, was higher in the Buc group (41.0%) than in the MTX (32.6%) and SASP groups (25.6%). These data support Buc as a candidate for being a first-line drug for the treatment of patients with RA.     

Efficacy profile of bucillamine in rheumatoid arthritis patients in a large observational cohort study,IORRA

Abstract

Bucillamine (Buc) is a disease-modifying antirheumatic drug (DMARD) developed in Japan, which has been used as one of the first-line DMARDs for the treatment of rheumatoid arthritis (RA) in Japan. However, direct comparison of this drug with standard DMARDs including sulfasalazine (SASP) and methotrexate (MTX) has been scarcely reported. We therefore tried to evaluate the clinical efficacy of Buc by analyzing the database from the long-term observational cohort study IORRA (previously known as J-ARAMIS). The cross-sectional analysis revealed that responses to Buc treatment were better in males, patients with shorter duration of illness, and those who were rheumatoid factor-negative. In the longitudinal analysis, although there was no marked difference among the baseline variables of patients with Buc, SASP, and MTX, the percentage of patients exhibiting moderate or good response to treatment, as rated using the European League Against Rheumatism improvement criteria, was higher in the Buc group (41.0%) than in the MTX (32.6%) and SASP groups (25.6%). These data support Buc as a candidate for being a first-line drug for the treatment of patients with RA.     

Factors predicting the response to low-dose methotrexate therapy in patients with rheumatoid arthritis: a better response in male patients

Abstract

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug (DMARD) throughout the world. In Japan, MTX is recommended by the Japanese Ministry of Health, Labour, and Welfare to be given as the second or third DMARD and at a dosage of no more than 8?mg/week. We analyzed the efficacy of MTX in Japanese patients with RA in order to determine whether it is comparable to that in Western countries, where 15–20?mg/week of MTX is used, as well as to elucidate the factors associated with the favorable response to MTX. Around 8?mg/week of MTX was effective in half of the RA patients in the current study, and male sex was the only factor associated with a good response to MTX from a multivariate regression model analysis. Some of the patients who had a poor response to MTX showed an improvement with the addition of bucillamine or prednisolone. For the remaining patients, an increase in the MTX dosage to more than 8?mg/week or the use of biologics such as the anti-tumor necrosis factor (TNF)-α monoclonal antibody may be required.     

Factors predicting the response to low-dose methotrexate therapy in patients with rheumatoid arthritis: a better response in male patients

Methotrexate (MTX) is the most commonly used disease-modifying antirheumatic drug (DMARD) throughout the world. In Japan, MTX is recommended by the Japanese Ministry of Health, Labour, and Welfare to be given as the second or third DMARD and at a dosage of no more than 8 mg/week. We analyzed the efficacy of MTX in Japanese patients with RA in order to determine whether it is comparable to that in Western countries, where 15–20 mg/week of MTX is used, as well as to elucidate the factors associated with the favorable response to MTX. Around 8 mg/week of MTX was effective in half of the RA patients in the current study, and male sex was the only factor associated with a good response to MTX from a multivariate regression model analysis. Some of the patients who had a poor response to MTX showed an improvement with the addition of bucillamine or prednisolone. For the remaining patients, an increase in the MTX dosage to more than 8 mg/week or the use of biologics such as the anti-tumor necrosis factor (TNF)-α monoclonal antibody may be required.     

Acceptability and usefulness of mizoribine in the management of rheumatoid arthritis in methotrexate-refractory patients and elderly patients, based on analysis of data from a large-scale observational cohort study

This report documents the results of a study performed to examine clinical use of mizoribine (MZR), using data from a large-scale prospective cohort study, IORRA (Institute of Rheumatology Rheumatoid Arthritis). The number of patients with RA entered in this study from October 2000 through October 2003 was 6238. Three hundred and six patients (4.9%) received MZR therapy. Mizoribine users who were taking methotrexate (MTX) (MTX–MZR group, n = 94) and over 70 years of age (elderly group, n = 45) were collected. Cumulative retention rates of MZR were calculated by Kaplan–Meier analysis. Median drug survival of MZR was 28 months for the poor responders to MTX and 43 months for the poor responders to MZR, with no significant difference between these groups. Cumulative retention rate of MZR in the elderly group did not show a significant difference compared to that in patients aged under 70 years. Ten patients (10.6%) in the MTX–MZR group and 10 patients (22.2%) in the elderly group experienced adverse effects of MZR. None of these adverse effects was serious. This study indicated that, although MZR has not been frequently prescribed for RA patients, it may be useful and relatively safe for patients who are poor responders to MTX as an additional regimen to MTX therapy as well as for elderly patients.     

Acceptability and usefulness of mizoribine in the management of rheumatoid arthritis in methotrexate-refractory patients and elderly patients,based on analysis of data from a large-scale observational cohort study

Abstract

This report documents the results of a study performed to examine clinical use of mizoribine (MZR), using data from a large-scale prospective cohort study, IORRA (Institute of Rheumatology Rheumatoid Arthritis). The number of patients with RA entered in this study from October 2000 through October 2003 was 6238. Three hundred and six patients (4.9%) received MZR therapy. Mizoribine users who were taking methotrexate (MTX) (MTX–MZR group, n = 94) and over 70 years of age (elderly group, n = 45) were collected. Cumulative retention rates of MZR were calculated by Kaplan–Meier analysis. Median drug survival of MZR was 28 months for the poor responders to MTX and 43 months for the poor responders to MZR, with no significant difference between these groups. Cumulative retention rate of MZR in the elderly group did not show a significant difference compared to that in patients aged under 70 years. Ten patients (10.6%) in the MTX–MZR group and 10 patients (22.2%) in the elderly group experienced adverse effects of MZR. None of these adverse effects was serious. This study indicated that, although MZR has not been frequently prescribed for RA patients, it may be useful and relatively safe for patients who are poor responders to MTX as an additional regimen to MTX therapy as well as for elderly patients.     

Ten years results of bucillamine in the treatment of rheumatoid arthritis

A 10-year cohort study was performed, involving all of the 118 patients treated with bucillamine in our hospital between 1988 and 1990. Evaluation was made on the basis of erythrocyte sedimentation rate, grip strength, joint score, duration of morning stiffness, and Lansbury index consisting of the above four parameters. Eleven patients were male and 107 were female, with a mean age of 53 years (range: 20-79 years) and a mean duration of illness of 8.2 years (range: 2-31 years). Lansbury index remained significantly suppressed throughout the 10-year period of treatment. Continuous treatment was possible for 10 years in 18 patients (15%: 2 men and 16 women). Stage of disease did not advance in 14 patients. Six patients met the criteria for remission. Of all patients, 50% dropped out of treatment at 2.4 years after the start of treatment and 75% at 5 years. The 100 patients who dropped out could be roughly divided into three groups. One third of them dropped out because of lack of or attenuation of response. Another third dropped out because of referral to other medical facilities or discontinuation of visits to our hospital, and the remaining third dropped out because of adverse reactions to treatment. There was no particular trend in terms of sex, age, duration of sickness, drugs used before bucillamine, or level of activity of rheumatoid arthritis. There were no significant difference in the stage and class of the disease, and other backgrounds between 10-year treatment group and dropout group.     

Long-term safety study of iguratimod in patients with rheumatoid arthritis

We conducted a 52-week clinical study of iguratimod in 394 Japanese patients with rheumatoid arthritis to evaluate the long-term safety of the drug. Iguratimod was administered orally at a daily dose of 25 mg for the first 4 weeks and 50 mg for the subsequent 48 weeks. Some of the patients continued the treatment for 100 weeks for their benefit. The cumulative incidence of adverse events for 100 weeks was 97.6%. The cumulative incidence of adverse reactions was 65.3%; unfavorable symptoms and signs (excluding abnormal laboratory data changes) accounted for 33.2% of the reactions, and abnormal laboratory data changes accounted for 50.4%. The continued treatment rate was 66.8% at week 28 and 53.6% at week 52. For reference, the American College of Rheumatology (ACR) 20 response rate was calculated for the patients who had assessable disease activity, who did not violate the study protocol, and who continued the study treatment at weeks 28 and 52. The rate was 46.9% at week 28 and 41.0% at week 52. To use iguratimod safely for a long time, patients should be observed closely for adverse reactions such as increased hepatic enzymes.     

Long-term safety study of iguratimod in patients with rheumatoid arthritis

Abstract

We conducted a 52-week clinical study of iguratimod in 394 Japanese patients with rheumatoid arthritis to evaluate the long-term safety of the drug. Iguratimod was administered orally at a daily dose of 25?mg for the first 4 weeks and 50?mg for the subsequent 48 weeks. Some of the patients continued the treatment for 100 weeks for their benefit. The cumulative incidence of adverse events for 100 weeks was 97.6%. The cumulative incidence of adverse reactions was 65.3%; unfavorable symptoms and signs (excluding abnormal laboratory data changes) accounted for 33.2% of the reactions, and abnormal laboratory data changes accounted for 50.4%. The continued treatment rate was 66.8% at week 28 and 53.6% at week 52. For reference, the American College of Rheumatology (ACR) 20 response rate was calculated for the patients who had assessable disease activity, who did not violate the study protocol, and who continued the study treatment at weeks 28 and 52. The rate was 46.9% at week 28 and 41.0% at week 52. To use iguratimod safely for a long time, patients should be observed closely for adverse reactions such as increased hepatic enzymes.     

Pharmacokinetics and efficacy of low-dose methotrexate in patients with rheumatoid arthritis

This article evaluates the relationship between the pharmacokinetics of methotrexate (MTX), its efficacy in the treatment of rheumatoid arthritis (RA), and serum folic acid (FA) levels. The pharmacokinetics of MTX was studied in 29 patients with RA treated with low-dose MTX. The weekly dose of MTX was given orally at 2–4mg every 12h over a period of 24–36h. Blood samples were taken 4h after the first administration in any given week. A Bayesian method was used to estimate individual MTX pharmacokinetic variables. We then investigated the efficacy of MTX and the serum FA levels in these patients. We examined C-reactive protein levels (CRP) and the erythrocyte sedimentation rate (ESR), and analyzed the values obtained before and after MTX treatment in order to evaluate the efficacy of the MTX treatment. The degree of improvement in CRP and ESR was significantly correlated with the length of time the MTX concentration–time curve remained above 0.02µM in one week. Furthermore, the degree of improvement in CRP was also significantly correlated with the area under the concentration–time curve (AUC) for MTX. These results suggest that serum MTX measurements could be useful in determining individual patient regimens.     

The efficacy and safety of bucillamine as a second-line DMARD in the treatment of rheumatoid arthritis: a retrospective cohort study

Abstract

We investigated the efficacy and safety of bucillamine administered as a second-line DMARD compared to administration as a first-line DMARD in the treatment of rheumatoid arthritis (RA). We conducted a retrospective cohort study and reviewed medical records of 86 patients with active RA who began to receive bucillamine at Yokohama Minami Kyosai Hospital between January 1998 and July 2004. The efficacy of treatments was compared based on rates of achievement of 20, 50, and 70% improvement in ACR core set 6 months after initiation of the therapy. In the group administered bucillamine as a first-line DMARD (18 patients), 44.4, 22.2, and 11.1% of patients achieved ACR 20, 50, 70, respectively, while 56.5, 34.1, and 19.5% achieved ACR 20, 50, 70, respectively, in the group administered bucillamine following switching from MTX (46 patients), and 53.3, 33.3, and 13.3% achieved ACR 20, 50, and 70, respectively, in the group administered bucillamine following switching from Sulfasalazine (SSZ) (15 patients). The rates of achievements of ACR 20, 50, 70 did not differ statistically between the three groups and there was no increase in risk of serious adverse effects related to previous DMARDs. The usefulness of bucillamine as a second-line DMARD was demonstrated.     

The efficacy and safety of bucillamine as a second-line DMARD in the treatment of rheumatoid arthritis: a retrospective cohort study

We investigated the efficacy and safety of bucillamine administered as a second-line DMARD compared to administration as a first-line DMARD in the treatment of rheumatoid arthritis (RA). We conducted a retrospective cohort study and reviewed medical records of 86 patients with active RA who began to receive bucillamine at Yokohama Minami Kyosai Hospital between January 1998 and July 2004. The efficacy of treatments was compared based on rates of achievement of 20, 50, and 70% improvement in ACR core set 6 months after initiation of the therapy. In the group administered bucillamine as a first-line DMARD (18 patients), 44.4, 22.2, and 11.1% of patients achieved ACR 20, 50, 70, respectively, while 56.5, 34.1, and 19.5% achieved ACR 20, 50, 70, respectively, in the group administered bucillamine following switching from MTX (46 patients), and 53.3, 33.3, and 13.3% achieved ACR 20, 50, and 70, respectively, in the group administered bucillamine following switching from Sulfasalazine (SSZ) (15 patients). The rates of achievements of ACR 20, 50, 70 did not differ statistically between the three groups and there was no increase in risk of serious adverse effects related to previous DMARDs. The usefulness of bucillamine as a second-line DMARD was demonstrated.     

A comparison between bucillamine and d-penicillamine in the treatment of rheumatoid arthritis

In order to compare the clinical effect and the frequency of side effects of d-penicillamine and bucillamine, we conducted a randomized, controlled clinical trial. Twenty-two and 24 patients were allocated to each section of the study, respectively. Bucillamine was at least as effective ad d-penicillamine in terms of improvement in the swollen joint count, tenderness score, morning stiffness, modified health assessment questionnaire, and Westergren erythrocyte sedimentation rate (ESR), and more effective in terms of improvement in the tender joint count, grip strength, C-reactive protein (CRP), and rheumatoid factor (RF) titer. In all, 27% of the bucillamine group and 33% of the d-peni-cillamine group responded; the response rate did not differ significantly between the two groups. The frequency of side effects tended to be lower in the bucillamine group. In conclusion, bucillamine was as effective as d-penicillamine in the treatment of rheumatoid arthritis, and with the former the frequency of side effects tended to be lower. Received: 30 April 1996 / Accepted: 2 December 1996     

Chronological changes in baseline disease activity of patients with rheumatoid arthritis who received biologic DMARDs between 2003 and 2012

Abstract

Background/Purpose. The use of biologic disease-modifying anti-rheumatic drugs (DMARDs) for rheumatoid arthritis (RA) has been increasing since 2003. In this study, we evaluated changes in the characteristics of patients receiving biologic DMARDs daily, in Japan.

Methods. The characteristics of all RA patients who received any biologic DMARD at the Institute of Rheumatology, Tokyo Women's Medical University, within 1 year after its approval in Japan, were retrospectively evaluated. The periods of patient enrollment for each biologic agent were: infliximab (IFX), 2003–2004; etanercept (ETN), 2005–2006; tocilizumab (TCZ), 2008–2009; adalimumab (ADA), 2008–2009; abatacept (ABT), 2010–2011; and golimumab (GLM), 2011–2012. We retrospectively collected individual patient characteristics, concomitant medication usage, and disease activity assessed by disease activity score 28 (DAS28) at the time of administration, from the medical records. The retention rate for each agent at 6 months after treatment initiation was also assessed.

Results. The numbers of patients who received each biologic DMARD at our institute within 1 year after its approval were: IFX, 49; ETN, 50; TCZ, 62; ADA, 52; ABT, 40; and GLM, 77. From 2003 to 2012, the proportion of patients with prior use of any biologic DMARD increased, as did concomitant use and dose of methotrexate (MTX); however, corticosteroid use and doses decreased. DAS28, at the time of treatment initiation, gradually decreased. At the time of IFX administration, 75% and 25% of patients had high and moderate disease activity respectively, compared to 25% and 58% respectively, of patients who received GLM. No significant difference was observed in the retention rate of biologic DMARDs at 6 months (range, 75.0% to 89.6%).

Conclusion. Baseline disease activity of RA patients who received biologic DMARDs between 2003 and 2012 has changed from high to moderate in daily practice in Japan.     

Modeling and cost-effectiveness analysis of etanercept in adults with rheumatoid arthritis in Japan: a preliminary analysis

Abstract

The tumor necrosis factor (TNF) antagonist etanercept is an antirheumatic agent which was approved by Japanese regulatory authorities in January 2005. In Japan, the cost-effectiveness of this therapy for patients with rheumatoid arthritis (RA) has not previously been evaluated. This study models the cost-utility of etanercept in comparison with standard therapy with disease-modifying antirheumatic drugs (DMARDs) among adult Japanese RA patients who have failed a previous course of the DMARD bucillamine. A Markov model with 6-month cycles was constructed to compare two therapeutic strategies: etanercept versus standard therapy. For each cycle, one of three options was possible: a patient could (i) remain on current therapy if American College of Rheumatology criteria for 20% clinical improvement (ACR20) were achieved, (ii) switch to another drug in the therapeutic pathway if ACR20 was not achieved or if side effects severe enough to cause treatment discontinuation occurred, or (iii) they could die. The therapeutic pathway for the etanercept strategy was etanercept, methotrexate (MTX), sulfasalazine (SSZ), combination therapy (MTX + SSZ) and, finally, no DMARD. The pathway for standard therapy was identical except the initial therapy was MTX (etanercept was excluded). Results from clinical trials in U.S. and European patient populations were used to derive model probabilities for disease progression, response to drug therapy, and relationships between ACR20 response and functional improvement as measured by the Health Assessment Questionnaire (HAQ) disability index. An equation was developed to predict utility from HAQ scores of Japanese patients. Costs for drugs and medical services in Japan were obtained for April 2003. Analysis was conducted from a societal perspective, including lost productivity costs due to RA disability and premature mortality. Costs were discounted at 6% annually, and quality-adjusted life years (QALYs) at 1.5% annually. Model parameters were varied by 20% above and below base-case values in sensitivity analyses. Compared to standard therapy, the etanercept strategy was ¥6.39 million more costly per patient but yielded an additional 2.56 QALYs. The incremental cost-utility ratio was ¥2.50 million/QALY. Sensitivity analyses revealed that cost-utility was most strongly influenced by the acquisition cost of etanercept and the percentage of etanercept recipients who achieved ACR20. Using commonly applied thresholds for acceptable cost-effectiveness in the United States ($50000 = ¥5.5 million/QALY) and the United Kingdom (£30000 = ¥5.7 million/QALY), etanercept therapy in Japan can be considered cost-effective. Cost-utility ratios did not exceed these thresholds in any sensitivity analysis. Further analyses should be conducted once clinical and epidemiologic data for Japanese patients become available.     

Safety and efficacy of combination therapy of iguratimod with methotrexate for patients with active rheumatoid arthritis with an inadequate response to methotrexate: An open-label extension of a randomized,double-blind,placebo-controlled trial

Abstract

Objective. To obtain safety and efficacy data on combination treatment with iguratimod and methotrexate (MTX) in an open-label extension study in patients with active rheumatoid arthritis (RA).

Methods. Following a 28-week, randomized, double-blind trial of adding iguratimod or placebo to stable MTX therapy, patients entered a 24-week extension. Patients randomized to the iguratimod + MTX group continued treatment. Patients treated with placebo + MTX switched to iguratimod + MTX [the (placebo/iguratimod) + MTX group].

Results. In the iguratimod + MTX group, the rate of 20% improvement in American College of Rheumatology criteria (ACR20) at week 52 (71.3%) was similar to that at week 24 (69.5%). ACR50, ACR70 and Health Assessment Questionnaire Disability Index at week 52 significantly improved compared with the values at week 24. In the (placebo/iguratimod + MTX) group, the switch to iguratimod treatment significantly improved ACR20 from 30.7% at week 24 to 72.1% at week 52. Frequent adverse events for 52 weeks in the iguratimod + MTX group were nasopharyngitis, upper respiratory tract inflammation, stomatitis, lymphocyte decrease, AST increase, ALT increase and blood iron decrease. These adverse events were predominantly mild or moderate in severity. No deaths occurred.

Conclusion. Efficacy and tolerance of iguratimod + MTX therapy was maintained to 52 weeks in patients with active RA with inadequate response to MTX.     

Modeling and cost-effectiveness analysis of etanercept in adults with rheumatoid arthritis in Japan: a preliminary analysis

The tumor necrosis factor (TNF) antagonist etanercept is an antirheumatic agent which was approved by Japanese regulatory authorities in January 2005. In Japan, the cost-effectiveness of this therapy for patients with rheumatoid arthritis (RA) has not previously been evaluated. This study models the cost-utility of etanercept in comparison with standard therapy with disease-modifying antirheumatic drugs (DMARDs) among adult Japanese RA patients who have failed a previous course of the DMARD bucillamine. A Markov model with 6-month cycles was constructed to compare two therapeutic strategies: etanercept versus standard therapy. For each cycle, one of three options was possible: a patient could (i) remain on current therapy if American College of Rheumatology criteria for 20% clinical improvement (ACR20) were achieved, (ii) switch to another drug in the therapeutic pathway if ACR20 was not achieved or if side effects severe enough to cause treatment discontinuation occurred, or (iii) they could die. The therapeutic pathway for the etanercept strategy was etanercept, methotrexate (MTX), sulfasalazine (SSZ), combination therapy (MTX + SSZ) and, finally, no DMARD. The pathway for standard therapy was identical except the initial therapy was MTX (etanercept was excluded). Results from clinical trials in U.S. and European patient populations were used to derive model probabilities for disease progression, response to drug therapy, and relationships between ACR20 response and functional improvement as measured by the Health Assessment Questionnaire (HAQ) disability index. An equation was developed to predict utility from HAQ scores of Japanese patients. Costs for drugs and medical services in Japan were obtained for April 2003. Analysis was conducted from a societal perspective, including lost productivity costs due to RA disability and premature mortality. Costs were discounted at 6% annually, and quality-adjusted life years (QALYs) at 1.5% annually. Model parameters were varied by 20% above and below base-case values in sensitivity analyses. Compared to standard therapy, the etanercept strategy was ￥6.39 million more costly per patient but yielded an additional 2.56 QALYs. The incremental cost-utility ratio was ￥2.50 million/QALY. Sensitivity analyses revealed that cost-utility was most strongly influenced by the acquisition cost of etanercept and the percentage of etanercept recipients who achieved ACR20. Using commonly applied thresholds for acceptable cost-effectiveness in the United States ($50 000 = ￥5.5 million/QALY) and the United Kingdom (￡30 000 = ￥5.7 million/QALY), etanercept therapy in Japan can be considered cost-effective. Cost-utility ratios did not exceed these thresholds in any sensitivity analysis. Further analyses should be conducted once clinical and epidemiologic data for Japanese patients become available.