[Small molecules treatment in rheumatoid arthritis]

If treatment target is not reached with a conventional disease-modifying antirheumatic drug (csDMARD) such as methotrexate in rheumatoid arthritis, it is recommended to use a biologic (bDMARD) or a Janus kinase (JAK) inhibitor, small synthetic molecules recently developed. Oral administration and short half-life can favour the choice of JAK inhibitors, as well as the opportunity to use it in monotherapy, even though co-treatment with csDMARD is recommended. As yet long-term studies are lacking, little is known about adverse effects although risk of herpes virus infections is clearly higher with JAK inhibitors than bDMARD treatments.