How would you approach the treatment of erosive inflammatory arthritis (RA or SpA) in a patient with multiple sclerosis on ocrelizumab who has failed csDMARD therapy?

This is a challenging situation to confront, however, as more non- rheumatological illnesses are being managed with biologics, we will be facing this issue with greater frequency.

Regarding multiple sclerosis (MS), one should be aware that the major metabolite of leflunomide, teriflunomide, is a brand-name product for MS. (Aubagio). Interestingly, the standard dose of 20 mg leflunomide metabolizes to 14 mg teriflunomide, which is the exact dose of the branded product. Therefore it is worth revie...

I agree with Dr. @Dr. First Last’s comments, particularly with respect to the idea of adding teriflunomide. I would also consider adding methotrexate. Ocrelizumab, like rituximab, targets CD20, and in the earliest clinical trials with rituximab, the drug was significantly more effective when used in combination with methotrexate. So, even if this patient had previously failed methotrexate, there may be benefit to adding it in this situation.

Finally, I agree that some of the newer biologics for...