Efficacy and safety of combination therapy for preventing bone damage in rheumatoid arthritis

The main outcomes of the therapies for rheumatoid arthritis (RA) must be preventing, or at least lessening, the development of structural damage. Biological disease-modifying anti-rheumatic drugs (bDMARDs), targeting tumour necrosis factor-α (TNF-α) or other key steps (IL-1, IL-6, T cells, B cells) in the pathogenesis of RA, have given clues to be effective and safe as treatments for RA, being capable of improving disease activity, ameliorating functional ability and halting joint damage. A large body of evidence, stemming from randomized clinical trials, observational studies, and registries, has shown that the beneficial effects of the bDMARDs become optimal when combined with synthetic (s)-DMARDs, mainly methotrexate (MTX). Despite combination therapy is advocated by the international guidelines for the management of RA, data from the daily standard of care indicate that almost one third of RA patients are treated with bDMARDs as monotherapy. Many reasons may be taken into account to explain this gap from official recommendations, among which the fact that in real-life settings, the assessment of clinical outcomes is exclusively based on clinical indices, disregarding the evolution of bone damage. Furthermore, some bDMARDs have been launched in the market with the official approval to be used as monotherapy. But even for the latter, there is no conclusive proof that monotherapy regimen is comparable to co-therapy with MTX in preventing articular damage. In conclusion, the most recent published data show that combination therapy with bDMARDs and MTX represents the best therapeutic option for the treatment of RA since it can stop or at least slow the progression of disabling structural damage.