To investigate the efficacy and safety of adalimumab plus methotrexate (MTX) for the treatment of rheumatoid arthritis (RA).
This is a multi-center, randomized, double-blind, parallel-group, and placebo-controlled clinical study, included a total of 302 cases of active rheumatoid arthritis, randomized into three groups of observation: 40 mg adalimumab (121 cases), 80 mg adalimumab (121 cases), or placebo (60 cases). Upon enrollment, all subjects had been previously treated with MTX for at least 3 months, and their doses of drug had remained stable for at least 28 days. The double-blind phase lasted for 12 weeks, during which the subjects were administered with adalimumab or placebo subcutaneously every other week. Then the subjects entered into another 12 weeks of open-label study, which included subcutaneous injection of 40 mg adalimumab every other week. In both the double-blind and the open-label periods, all subjects were maintained concomitantly with MTX that had already been used before this study. The primary efficacy variables were evaluated on basis of American College of Rheumatology (ACR)20 response rate at week 12. The secondary efficacy variables included: ACR20 response rate at week 24; ACR50 and ACR70 response rates at weeks 12 and 24; and changes at weeks 12 and 24 compared with baseline observations for tender and swollen joint counts, as well as the assessment of pain with visual analog scale (VAS), the physician's and the patient's global assessment of disease activity (VAS), and the analysis on health assessment questionnaire (HAQ) and health related quality of life (HRQL) measured by Short Form-36 (SF-36); The safety variables mainly included adverse events (AE).
During the double-blind period, subjects treated with 40 mg of adalimumab, 57.0% achieved ACR20 response at week 12 (P = 0.004 versus placebo), and subjects treated with 80 mg of adalimumab, 51.2% achieved ACR20 response at week 12 (P = 0.026 versus placebo), and only 35.0% of subjects treated with placebo achieved ACR20 response at week 12. On the other hand, 32.2% of subjects receiving 40 mg of adalimumab achieved ACR50 response (P = 0.009 versus placebo), and 15.7% achieved ACR70 response (P = 0.007 versus placebo) at week 12. Subjects treated with 40 mg of adalimumab got a better result versus placebo at week 12 for tender joint count, swollen joint count, and improvement in C-reactive protein; and subjects treated with 80 mg of adalimumab were also seen an amelioration versus placebo at week 12 for swollen joint count, and improvement in C-reactive protein; all of these findings were statistically significant in differences. During the open-label period all subjects received 40 mg of adalimumab, and response rates for ACR20, ACR50, and ACR70 in the two treatment groups of 40 mg and 80 mg adalimumab were maintained or improved from week 12 to week 24 (being 73.1%, 40.3% and 17.6% respectively for 40 mg group; 71.1%, 39.5% and 17.5% respectively for 80 mg group); while response in the original placebo group (being 67.8%, 44.1% and 18.6%) increased during the 12-week open-label period to match that of the original adalimumab treatment groups. While for changes in tender and swollen joint counts, VAS, HAQ, SF-36, a significant improvement was seen at week 24 when compared with baseline and week 12 values. Throughout the double-blind and open-label period, adverse events reported in >/= 5% of subjects at least possibly associated with the study drug were upper respiratory tract infection, nasopharyngitis, and injection site itching, mostly being mild to moderate in severity. There were 3 cases of tuberculosis reported during this study. And 3 cases of serious adverse event (SAE) were reported among the adalimumab subjects during the double-blind period, which were determined as unrelated or probably unrelated to the study drug. And 8 cases (2.7%) of SAE were seen among the adalimumab subjects during the open-label period, 3 of which were at least possibly unrelated with the study drug. All SAEs reported were consistent to those seen in other adalimumab trials. No other unexpected safety signals were reported.
Adalimumab plus MTX is better than single MTX in efficacy for the treatment of RA. Being generally safe and well tolerated, adalimumab plus MTX can significantly increase the response rate, continuously reduce the arthritic signs, symptoms and the inflammatory factors in patients, and also be helpful for reducing disabilities and improving the global quality of life for the patients.