A Phase 2 Trial of Tobevibart plus Elebsiran in Hepatitis D
Tarik Asselah, Michael A. Chattergoon, Alina Jucov, Anca Streinu-Cercel, Pietro Lampertico, Heiner Wedemeyer, Patrick T. Kennedy, Edward Gane, Brianna L. Bullard, Sophia Chow, Desiree Santos, Grégory Camus, Yimeng Lu, Cara Pilowa, Carey Hwang, Todd Correll, Kosh Agarwal
Abstract
BACKGROUND: Both tobevibart (a monoclonal antibody) and elebsiran (a small interfering RNA) target hepatitis B virus surface antigen (HBsAg). Their efficacy and safety in the treatment of chronic hepatitis D virus (HDV) infection are unknown. METHODS: IU per milliliter from baseline (virologic response) and normalization of the alanine aminotransferase (ALT) level, at week 24. RESULTS: At week 24, a combined response was observed in 47% of participants (15 of 32) who received tobevibart plus elebsiran and in 70% of participants (23 of 33) who received tobevibart, with a virologic response in 100% (32 of 32) and 82% (27 of 33), respectively, and normalization of the ALT level in 47% (15 of 32) and 76% (25 of 33). At week 48, a combined response was observed in 56% of participants (18 of 32) with tobevibart plus elebsiran and 61% of participants (20 of 33) with tobevibart; undetectable HDV RNA (also known as target not detected, or TND; no amplification during reverse-transcriptase-polymerase-chain-reaction assay) in 66% (21 of 32) and 48% (16 of 33), respectively; normalization of the ALT level in 56% (18 of 32) and 61% (20 of 33); and an HBsAg level below 10 IU per milliliter in 91% (29 of 32) and 21% (7 of 33). No ALT flares were observed in participants starting tobevibart and elebsiran simultaneously or receiving tobevibart monotherapy. Through week 48, a total of 81% of participants who received tobevibart plus elebsiran and 94% of those who received tobevibart had at least one adverse event, primarily influenza-like illness and chills. CONCLUSIONS: In this phase 2 trial, tobevibart plus elebsiran as well as tobevibart monotherapy decreased HDV RNA and ALT levels through week 48. Treatment with tobevibart plus elebsiran was associated with a high incidence of undetectable HDV RNA and of a decrease in the HBsAg level. (Funded by Vir Biotechnology; ClinicalTrials.gov number, NCT05461170.).