Long‐term results of a phase 1/1b study of ibrutinib plus umbralisib for relapsed/refractory chronic lymphocytic leukemia - Christine E. Ryan; Yue Ren; Svitlana Tyekucheva; Jon E. Arnason; Adam M. Boruchov; Caron A. Jacobson; David C. Fisher; Hari Miskin; Peter Sportelli; Jennifer R. Brown; Matthew S. Davids (HemaSphere)