抄録
The methotrexate scored tablet, Metolate® tablet 2 mg (MTL), was developed for use by patients with rheumatoid arthritis (RA) in Japan as a generic version of the methotrexate capsule, Rheumatrex® capsule 2 mg (brand-name drug). Therefore, MTL had no clinical evidence for use with RA patients until we conducted a post-marketing observational study to collect clinical data concerning the safety and efficacy of the drug. On the other hand, we conducted another post-marketing observational study of switchover to MTL in stable RA patients previously on long term brand-name drug therapy to confirm the therapeutic equivalence of the two formulations and the patient satisfaction with the MTL substitution. As a result, no significant differences were seen in the duration of morning stiffness, CRP and ESR levels, grip strength, tender and joint counts, DAS28(3)-CRP, or DAS28(3)-ESR three months before and after MTL substitution. For safety, the incidence of adverse drug reactions (ADR) was 6.2% (22/357) after MTL substitution and most ADR were common in brand-name drug therapy as well. Patient satisfaction with the MTL substitution was assessed by investigators asking the patient to compare it with the brand-name drug. Most patients were satisfied that the MTL substitution had caused “no change” and more patients believed their situation had “improved” than “worsened”. In conclusion, MTL was considered to be the therapeutically equivalent to the brandname drug.
