Comment on "cannabidiol synergizes with methotrexate to attenuate rheumatoid arthritis via STAT3/NF-κB...

Xu et al. reported that cannabidiol (CBD) enhanced the therapeutic effect of methotrexate (MTX) in experimental rheumatoid arthritis and attributed this benefit mainly to suppression of STAT3/NF-κB-driven M1 macrophage polarization. While the study is of interest and raises a potentially relevant MTX-sparing concept, we believe that several conclusions are stronger than the data currently support. In particular, superiority of a single combination regimen over selected monotherapy groups does not, by itself, establish true pharmacological synergy, which generally requires a formal interaction analysis across a dose matrix. In addition, the absence of pharmacokinetic assessment leaves an important translational gap, as CBD may not be pharmacologically neutral when co-administered with MTX, and short-term histology alone cannot exclude altered drug handling or cumulative toxicity. We also question whether the mechanistic interpretation is sufficiently resolved, given that the binary M1/M2 framework does not fully reflect the current understanding of macrophage heterogeneity in rheumatoid synovium. We therefore consider this study hypothesis-generating rather than mechanistically or pharmacologically definitive, and we suggest that a more restrained interpretation would better reflect the level of evidence provided.