Japan College of Rheumatology guidance for the use of methotrexate in patients with rheumatoid arthritis: Secondary publication.

Methotrexate (MTX), the anchor drug in the current treatment strategy for rheumatoid arthritis (RA), was first approved for the treatment of RA in Japan in 1999 at a recommended dose of 6-8 mg/week. The approved maximum dose of MTX has been 16 mg/week since February 2011 when MTX was approved as a first-line drug in the treatment of RA. Recent evidence of MTX-polyglutamate concentration in the red blood cells of Japanese patients with RA justifies the current daily use of MTX in Japan. Additionally, after a nationwide clinical trial, a subcutaneous MTX injection formula (7.5-15 mg/week) was approved for RA treatment in September 2022. Therefore, in March 2023, a subcommittee of the Japan College of Rheumatology updated the guidance (formerly 'guidelines') for the use of MTX in Japanese patients with RA. This article, an abridged English translation summarizing the 2023 update of the Japan College of Rheumatology guidance for the use of MTX and management of patients with RA, will be helpful to both Japanese and global rheumatology communities.