Hep B cure failure hits the Assembly line

Achieving a functional cure is the ultimate goal in hepatitis B, but Assembly has widely missed the mark with its first attempt. Study 211 was testing whether sustained virological response (SVR) could be achieved after withdrawing vebicorvir, its lead core inhibitor, from virally suppressed patients. An SVR rate of at least 15% at 24 weeks was the aim, but data released yesterday showed that 39 of 41 patients had relapsed within 16 weeks. Shares in the company plummeted 68% in early trading, and the failure also raises big question marks over the rest of company’s pipeline of core inhibitors. With its approach Assembly was trying to achieve more complete suppression of viral turnover, which it hoped would result in decay of residual virus, and a functional cure. The next-generation assets ABI-H2158 and ABI-H3733 are said to be more potent, but this setback will make it hard to justify pursuit of this theory. Further studies of vebicorvir are planned, however, under collaborations with Beigene and Arbutus; progress of a combination with Arbutus’s RNAi-based project will now take on greater importance.

Assembly's plans for its hep B assets
Status Project 2026e sales ($m) Note
Phase II Vebicorvir
1,582* Ph2 OLE study 211 (nuc combo), meaningful SVR rates not achieved
Ph3 registrational trial to start H1 2021 for chronic suppressive therapy in partially virologically suppressed population (Beigene collab)
Ph2 triple combo with AB-729 (RNAi from Arbutus) to start H1, Ph2 triple combo with interferon also to start H1
  ABI-H2158 - Ph2 data due 2021, '2158 plus Baraclude (nuc) in treatment-naive patients with HBeAg +ve chronic HBV (NCT04398134)
Phase I ABI-H3733 - Ongoing study following single ascending dose and multiple ascending doses in healthy subjects (NCT04271592)
*Consensus prior to Study 211 data, sources: EvaluatePharma, clinicaltrials.gov & company releases.

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