Landmark papers on the discovery of methotrexate for the treatment of rheumatoid arthritis and other systemic inflammatory rheumatic diseases: a fascinating story.

This review highlights the story of how methotrexate (MTX), a drug discovered for the treatment of childhood leukemia, became the mainstay of treatment and the standard-of-care for rheumatoid arthritis (RA) and was also found useful for several additional related rheumatological diseases. As against several synthetic disease-modifying antirheumatic drugs (csDMARDs) for treating RA that were discovered serendipitously, the use of low-dose MTX (LD-MTX) was based on sound reasoning and astute observations made in the 1940s and 1950s. The difference between high-dose MTX (HD-MTX) used in the treatment of childhood leukaemia and other malignancies as against LD-MTX used in rheumatology is emphasized.