LAUSR

7547Background: Acalabrutinib, a highly selective, potent, covalent BTK inhibitor, was assessed as monotherapy in pts with R/R de novo DLBCL. Methods: Eligible pts aged ≥18 y, with ECOG PS ≤2 and confirmed R/R non-germinal center (GCB) type DLBCL assessed by local IHC received oral acalabrutinib 100 mg bid until progressive disease (PD) or unacceptable toxicity. The primary endpoint was safety. Secondary endpoints included pharmacokinetics (PK), pharmacodynamics and investigator-assessed overall response rate (ORR; per Lugano criteria), duration of response (DOR) and progression-free survival (PFS). Results: 21 pts enrolled. To most recent prior therapy, 11 were relapsed (rel; partial response or better [≥PR], then PD), 10 were refractory (ref; no response/stable disease). Median age was 64 y (range 32-84); 86% had ECOG PS ≤1; 57% had extranodal disease; 81% had Ann Arbor stage III/IV; median no. of prior therapies was 3 (range 1-5). Median time on study was 3.9 mo (range 0.8-22.5); 1 pt continues therapy...