Pevifoscorvir Shows Strong HBV Activity, Durable Antigen Suppression

Why It Matters

The therapy could deliver a functional cure for chronic hepatitis B by targeting cccDNA, a key barrier that current nucleos(t)ide analogues cannot eliminate, reshaping treatment duration and outcomes.

Key Takeaways

• ALG‑001075 EC₅₀ 0.64 nM, far outperforms canocapavir and neracorvir
• 96‑week pevy monotherapy cut HBsAg by >1 log, sustained off‑treatment
• Resistance mutation T33N reduced activity, but not observed in treated patients
• LHBs decline suggests cccDNA‑derived antigen reduction, hinting at finite therapy
• FDA granted Fast Track, phase 2 B‑SUPREME results expected 2027

Pulse Analysis

The chronic hepatitis B market has long relied on nucleos(t)ide analogues that suppress viral replication but seldom eliminate hepatitis B surface antigen (HBsAg). Persistence of covalently closed circular DNA (cccDNA) and integrated viral sequences fuels ongoing antigen production. Capsid assembly modulators (CAMs) address this gap by disrupting core protein functions, blocking pre‑genomic RNA encapsidation, and in some cases reducing antigen secretion. Among CAMs, pevifoscorvir (ALG‑001075) stands out with nanomolar EC₅₀ values that markedly outperform canocapavir and neracorvir. These pharmacologic advantages translate into lower dosing requirements and a broader therapeutic window.

Phase 1 results presented at EASL 2026 show that 96 weeks of pevifoscorvir 300 mg daily lowered HBsAg by more than one log10 unit, a reduction that held steady during a 24‑week entecavir follow‑up. The pronounced drop in large‑surface HBsAg isoforms—primarily cccDNA‑derived—implies a genuine shrinkage of the active viral reservoir. Although the T33N resistance mutation reduced in‑vitro potency, it was not detected in any treated participant, indicating a reassuring resistance profile. Moreover, the modest rebound in HBV DNA during entecavir transition underscores the complementary role of nucleos(t)ide analogues. These data move the field closer to a finite functional cure.

The FDA’s Fast Track designation reflects confidence that pevifoscorvir could address an unmet need in HBV therapy. The ongoing phase 2 B‑SUPREME trial, expected to read out in 2027, will test whether the antigen‑suppressive signal translates into higher HBsAg‑loss rates in a larger population. Success would enable shorter, off‑drug treatment courses, reshaping clinical guidelines and payer reimbursement models. If confirmed, pevifoscorvir could also reduce long‑term liver disease complications, enhancing its value proposition. As other late‑stage CAMs and RNA‑targeted agents advance, pevifoscorvir’s potency and durability position it as a potential market leader in functional‑cure strategies.