Arbutus Halts COVID-19 RNA Destabilization Projects After Reviewing Early Preclinical Data

Arbutus Biopharma has undertaken a substantial shift in its strategic direction, opting to withdraw from its involvement in COVID-19 research and discontinue its RNA destabilization projects. Instead, the company is redirecting its attention towards hepatitis B, a decision rooted in a combination of factors, including unfavorable outcomes observed in preclinical studies.

Among the notable endeavors within Arbutus’ portfolio was AB-343, an oral therapy designed specifically to combat the SARS-CoV-2 main protease, which is a critical target in the treatment of COVID-19. The biotech had also been exploring a combination therapy, seeking to harness the potential synergy between AB-343 and a promising nsp12 polymerase inhibitor. Unfortunately, the outcome of preclinical investigations revealed a discouraging “unfavorable” pharmacokinetic profile, prompting Arbutus to make the difficult decision to terminate its COVID-19 initiatives.

Similarly, Arbutus had been diligently working on AB-161, a project focused on RNA destabilization. However, the company recently disclosed that it would be discontinuing AB-161 due to a preclinical toxicology finding that was unrelated to peripheral neuropathy. It is noteworthy that AB-161 had already advanced to the phase 1 trial stage for hepatitis B virus, and it’s important to emphasize that no safety concerns had arisen during this phase among the healthy participants.

These strategic decisions are expected to significantly extend Arbutus’ financial runway, providing financial stability until at least the third quarter of 2025. This move aligns with the company’s anticipation of several critical milestones. Firstly, there is the eagerly awaited preliminary data from a phase 2a trial evaluating the RNAi therapeutic, imdusiran, in combination with Vaccitech’s antigen-specific immunotherapy VTP-300 for chronic hepatitis B virus, scheduled for release in the fourth quarter of the current year.

Subsequently, there is the impending release of preliminary data from a phase 1 trial involving the oral PD-L1 inhibitor, AB-101. Despite encountering an FDA clinical hold in April, Arbutus has gained approval to proceed with this trial in New Zealand, with data anticipated to emerge in the first half of the upcoming year. CEO William Collier has expressed his enthusiasm for AB-101, characterizing it as “highly potent” and highlighting its demonstrated efficacy against PD-L1 in cells derived from individuals with chronic HBV. Collier has also put forward the notion that checkpoint inhibitors may have a role to play in the context of antiviral immune tolerance in chronic HBV.

However, it’s worth underscoring that Arbutus faces challenges that transcend its strategic adjustments. The company is currently embroiled in legal disputes with industry giants Moderna and Pfizer-BioNTech, alleging patent infringement related to its lipid nanoparticle delivery system. These legal proceedings are ongoing, with a pivotal claim construction hearing set for February 7, 2024, in the case against Moderna.

It’s important to recognize that these recent decisions to exit the COVID-19 research arena and halt RNA destabilization projects are not the first instances of pipeline modifications for Arbutus. In 2019, the company made the difficult choice to terminate a phase 1 medication following the occurrence of acute hepatitis in two healthy participants. Less than six months later, another setback occurred when a preclinical candidate for hepatitis B was abandoned due to safety concerns arising from animal studies. In November 2022, Arbutus also decided to discontinue an oral capsid inhibitor.

The post Arbutus Halts COVID-19 RNA Destabilization Projects After Reviewing Early Preclinical Data appeared first on LifeSci Voice.