Phase 3 randomized, double-blind, placebo-controlled, study to evaluate the efficacy and safety of acalabrutinib plus rituximab,cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) as compared with placebo plus R-CHOP in subjects ≤75 years of age with previously untreated non-germinal center diffuse large B-cell lymphoma (activated B-cell (ABC) and unclassified).