Mepolizumab works in much the same way by targeting interleukin (IL) 5, which Dr. Seo called “Miracle-Gro for eosinophils.” Weeding out eosinophils can knock back EGPA.
Giant cell arteritis (GCA), associated with blindness and stroke, may respond to anti-IL-6 inhibition. Tocilizumab (Actemra) gets rid of IL-6, and a phase 3 clinical trial (GiACTA) concluded that GCA patients on the drug were much less likely to flare as they tapered prednisone use, compared to patients on prednisone and a placebo.1 In response, the FDA approved tocilizumab for GCA in 2017. Not everyone has benefited: clinical trial data suggest that tocilizumab has been less effective in treating Takayasu’s arteritis, a large vessel vasculitis seen more often in younger women.
The third treatment category relies on inhibition of immune targeting, such as blocking or eliminating the antibodies used by the immune system to tag and attack blood vessels. “They can’t hurt you if they can’t find you,” Dr. Seo said. Recent reports from a large multinational study, PEXIVAS, suggest that plasmapheresis, or removing antibodies via plasma exchange, wasn’t effective in significantly reducing mortality or the risk of end-stage renal disease among ANCA-associated vasculitis patients, although the investigators stress the analysis is not yet complete.