When a patient with a preexisting rheumatic disease and on immunotherapy begins to flare, how do you decide if this is an underlying rheumatic disease activity versus an immunotherapy related adverse event?

If the symptoms/signs are similar to their prior flares of their rheumatic disease, then it is likely a flare. Over 50% of patients with autoimmune diseases flare on immune checkpoint inhibitor therapy if you look at systematic literature reviews of the limited published data.

If symptoms are unrela...