In a significant setback, Vivek Ramaswamy-backed Arbutus Biopharma is ceasing the development of its experimental hepatitis B therapy, after two healthy volunteers contracted serious liver infection in an early-stage trial.

The therapy, AB-506, is an oral hepatitis B virus (HBV) capsid inhibitor designed to thwart viral reproduction, versus existing standard therapies primarily nucleoside analogues that are designed to diminish viral replication.

The two subjects are experiencing resolution of their acute hepatitis. We will continue to follow them and the other study participants said Arbutus chief development officer Gaston Picchio said in a statement on Thursday afternoon.

The companys shares $ABUS sank about 30% to $1 in Friday premarket trading.

The Phase Ia/Ib trial was testing AB-506 in healthy subjects as well as patients with chronic HBV. and HBV-DNA positive subjects with chronic HBV infection. The tranche of healthy volunteers were given AB-506 doses ranging from 30-1000 mg while chronic HBV patients were given different doses of AB-506, with or without a nucleoside analogue.

In July, Arbutus provided a positive update on the trial, reporting that no serious adverse events or clinically significant safety findings were observed in the 33 healthy subjects, adding that ALT levels and other liver function tests were normal throughout the ten days of dosing. Although there were no serious side-effects observed in the group of 24 chronic hep B patients, there were four cases of ALT flares.

On Thursday, the Canadian company provided an update after 28 days of dosing and said the full dataset would be unveiled at a scientific conference later this year.

Terminating the AB-506 program also means Arbutus $ABUS will not initiate a combination study of AB-506 and its experimental RNAi therapy, AB-729, in the second half of 2020, it added.

AB-506 is Arbutus latest casualty. Last October in an announcement unveiling the appointment of Picchio the company said its experimental HBV RNA de-stabilizer, AB-452, will be delayed entering Phase I studies, after some long-term toxicity issues in animal studies emerged.

(T)his latest setback, raises questions about the companys small molecule design capabilities, Chardan analysts wrote in a note on Friday.

Arbutus, formerly known as Tekmira, pivoted from its Ebola effort to hep B after the acquisition of OnCore from a group of Pharmasset vets in 2015. In 2017, crushed by the failure of his Alzheimers bet, Roivants Vivek Ramaswamy who was already an investor invested a further $116.4 million at a premium rate to acquire preferred shares in Arbutus. Last year, Ramaswamy and Arbutus joined forces to spawn Genevant Sciences to develop a slate of RNA-based therapeutics backed by Arbutus proprietary lipid nanoparticle and ligand conjugate delivery technologies.

Arbutus Lipid Nanoparticle technology, which enables RNAi drugs to be encapsulated in tiny particles made of lipids that travel through the bloodstream to target tissues, was used by Alnylam $ALNY to develop its pioneering RNAi therapy, Onpattro, securing a stream of royalty revenue for Arbutus.

See more here:
Two acute cases of liver disease in healthy subjects kill Arbutus' hep B program - Endpoints News

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