What is your next step in patients with polymyositis without interstitial lung disease who are refractory to methotrexate?

In general, first-line treatment for myositis patients includes methotrexate, azathioprine or CellCept. The exact choice of agent depends on concomitant manifestations of the disease, like lung disease or arthritis, and can move on to the next one if they fail one of them. At the same time though, we see that specific autoantibodies respond favorably to specific agents and can change the order of drugs. For example, anti-HMGCR immune-mediated necrotizing myopathy responds to IVIG, so might choose that in favor of others.

Another issue with treating "polymyositis" is to verify the diagnosis and differentiate from other myopathies not amenable to immunosuppression, like inclusion body myositis.