Safety of acalabrutinib (Acala) monotherapy in hematologic malignancies: Pooled analysis from clinical trials

8064 Background: Acala is a next-generation, highly selective, covalent Bruton tyrosine kinase inhibitor approved in the US for patients (pts) with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and previously treated mantle cell lymphoma (MCL). We evaluated the safety profile of acala monotherapy (monotx) in multiple B cell malignancies. Methods: Data from pts with activated B-cell diffuse large B-cell lymphoma, CLL, follicular lymphoma, MCL, multiple myeloma, prolymphocytic leukemia, Richter syndrome, SLL, or Waldenström macroglobulinemia treated with ≥1 dose of acala monotx in 9 studies were pooled. Acala was administered at 100 mg BID in most pts (100–400 mg total dose daily). Adverse events (AE) were assessed. Results: A total of 1040 pts were included (median age: 67 y [range: 32–90]; ECOG status ≤1: 93%; median exposure duration: 24.6 mo [range: 0–58.5]). A total of 360 (34%) pts discontinued acala, most commonly due to progressive disease (PD; 17%). AEs led to acala discontinuation in 97 (9%) pts; those in > 2 pts were pneumonia (n = 5) and thrombocytopenia (n = 4). Incidence of AEs, including the most common (any grade and grade ≥3), are shown in the Table. Events of clinical interest (ECIs) included atrial fibrillation (afib) of any grade in 46 (4%) pts and grade ≥3 in 13 (1%) pts; major hemorrhage (any grade) in 37 (4%) pts; grade ≥3 infection in 183 (18%) pts; hypertension (any grade) in 79 (8%) pts and grade ≥3 in 36 (4%) pts; and second primary malignancies (SPM) excluding non-melanoma skin cancer (NMSC; any grade) in 68 (7%) pts. Median (range) time to first onset in days for each ECI (any grade) was: afib, 522 (8–1280); major hemorrhage, 293 (4–1327); infections, 92 (1–1317); hypertension, 157 (2–1345); SPM excluding NMSC, 339 (7–1499). Death was reported in 139 (13%) pts, most commonly due to PD (6%) and AEs (5%). Conclusions: Acala monotx has a favorable tolerability profile with increased exposure across multiple mature B cell malignancies. Additional analyses will further explore the longitudinal characteristics of AEs. [Table: see text]