BACKGROUND AND AIMS: The safety and tolerability of bulevirtide (BLV), a novel entry inhibitor of hepatitis delta virus, were evaluated in an integrated analysis of clinical trial results from patients with chronic hepatitis delta (CHD). METHODS: Week 48 on-treatment clinical and laboratory results from two Phase 2 trials (MYR203 [NCT02888106] and MYR204 [NCT03852433]) and one Phase 3 trial (MYR301 [NCT03852719]) were pooled (N = 269). Patients were grouped as follows: BLV 2 mg (n = 64), BLV 10 mg (n = 115), pegylated interferon-alfa (n = 39) and control (n = 51). The control group consisted of patients assigned to the delayed treatment group in Study MYR301. RESULTS: Adverse events (AEs) that occurred more frequently with BLV 2 mg and BLV 10 mg versus control included increased total bile acid levels (20% and 17% vs. 0%), injection-site reactions (16% and 20% vs. 0%), headache (16% and 17% vs. 0%), pruritus (11% and 10% vs. 0%) and eosinophilia (9% and 4% vs. 0%). Increases in total bile acid levels were observed with BLV without clear correlation with AEs, such as pruritus, eosinophilia or vitamin D deficiency. Grade 3 or 4 study drug-related AEs occurred in a higher proportion of patients receiving pegylated interferon-alfa (51%) than with BLV 2 or 10 mg (3% and 4%, respectively). There were no serious AEs related to BLV, and no patients discontinued BLV due to an AE. Neither hepatic decompensation nor death occurred. CONCLUSIONS: BLV monotherapy was safe and well tolerated through 48 weeks of treatment in patients with CHD. TRIAL REGISTRATION: NCT02888106, NCT03852433 and NCT03852719.