Zanubrutinib in patients with treatment‐naïve or relapsed/refractory Waldenström macroglobulinemia: An expanded‐access study of 50 patients in the United States

TABLE 1 Best overall response by investigator assessment in efficacy evaluable population Patients Dose Best overall assessment, n (%) TN (n = 11) R/R (n = 30) 160 mg BID (n = 33) 320 mg QD (n = 8) Overall * (N = 41) Very good partial response 3 (27) 13 (43) 13 (39) 3 (38) 16 (39) Partial response 4 (36) 10 (33) 12 (36) 2 (25) 14 (34) Minor response 1 (9) 4 (13) 4 (12) 1 (13) 5 (12) Stable disease 2 (18) 0 (0) 1 (3) 1 (13) 2 (5) Progressive disease 1 (9) 3 (10) 3 (9) 1 (13) 4 (10) Very good partial response or complete response 3 (27) 13 (43) 13 (39) 3 (38) 16 (39) Major response rate † 7 (64) 23 (77) 25 (76) 5 (63) 30 (73) Overall response rate ‡ 8 (73) 27 (90) 29 (88) 6 (75) 35 (85) * Nine patients were excluded from the efficacy evaluable population, as they discontinued prior to the first response assessment without clinical PD or death; 41 patients, who had ≥1 response evaluation while in the study, were included in the efficacy evaluable population. † Partial response or better. ‡ Very good partial response, partial or minor response. TABLE 2 Adverse events of special interest and dose modifications due to adverse event Adverse events, n (%) (safety population) Zanubrutinib 160 mg BID (n = 41) Zanubrutinib 320 mg QD (n = 9) Overall (N = 50) ≥1 TEAE of special interest * (category) 31 (76) 5 (56) 36 (72) Anaemia 2 (5) 0 (0) 2 (4) Atrial fibrillation and flutter 1 (2) 0 (0) 1 (2) Haemorrhage 16 (39) 3 (33) 19 (38) Hypertension 5 (12) 0 (0) 5 (10) Infections 15 (37) 2 (22) 17 (34) Neutropenia 2 (5) 0 (0) 2 (4) Second primary malignancies 4 (10) 0 (0) 4 (8) Thrombocytopenia 1 (2) 1 (11) 2 (4) Tumour lysis syndrome 0 (0) 0 (0) 0 (0) Grade ≥3 TEAEs of special interest 7 (17) 1 (11) 8 (16) Hypertension 4 (10) 0 (0) 4(8) Hypertension 4 (10) 0 (0) 4 (8) Procedural hypertension 1 (2) 0 (0) 1 (2) Infection 3 (7) 1 (11) 4 (8) Pneumonia 1 (2) 1 (11) 2 (4) COVID-19 pneumonia 1 (2) 0 (0) 1 (2) Cellulitis 1 (2) 0 (0) 1 (2) Staphylococcal bacteraemia 1 (2) 0 (0) 1 (2) Atrial fibrillation and flutter 1 (2) 0 (0) 1 (2) Neutropenia 1 (2) 0 (0) 1 (2) Second primary malignancy 1 (2) 0 (0) 1 (2) Soft tissue sarcoma 1 (2) 0 (0) 1 (2) TEAEs leading to treatment discontinuation † 1 (2) 2 (22) 3 (6) TEAEs leading to dose reduction 3 (7) 1 (11) 4 (8) *TEAE of special interest categories were defined as haemorrhage, atrial fibrillation/flutter, hypertension, second primary malignancies, tumour lysis syndrome, infections, neutropenia, thrombocytopenia, and anaemia. Patients’ char