P1027: RESPONSES TO AVAPRITINIB IN PATIENTS WITH ADVANCED SYSTEMIC MASTOCYTOSIS: HISTOPATHOLOGIC ANALYSES FROM EXPLORER AND PATHFINDER CLINICAL STUDIES oleh T. George, K. H. Karner, K. A. Moser, A. Rets, A. Reiter, D. H. Radia, M. Deininger, H.-M. Lin, S. Dimitrijević, D. J. DeAngelo