Arbutus Biopharma presented promising data at the EASL Congress 2025 for its chronic hepatitis B (cHBV) treatments, imdusiran and AB-101. Phase 2a clinical trial data showed that imdusiran, combined with VTP-300 and low-dose nivolumab, achieved functional cure in some patients, particularly those with baseline HBsAg levels below 1000 IU/mL. Furthermore, Arbutus presented data on AB-101, an oral PD-L1 inhibitor, demonstrating its safety and tolerability in cHBV patients.
The positive results from the IM-PROVE II trial are particularly encouraging for the cHBV treatment landscape. Achieving functional cure, defined as HBsAg loss and seroconversion, remains a significant challenge. The data suggest that combining imdusiran, which reduces HBV viral proteins, with therapies that stimulate the immune system, like VTP-300 and low-dose nivolumab, offers a viable pathway towards functional cure. This approach is especially relevant for a substantial portion of the cHBV population with HBsAg levels below 1000 IU/mL, who appear to respond more favorably to this combination therapy. The safety profile observed in the trial, with no serious adverse events or immune-related complications, further strengthens the potential of this treatment regimen.
In the IM-PROVE II trial, three patients in the combination therapy group (imdusiran, VTP-300, and nivolumab) achieved functional cure. Specifically, 25% of patients with baseline HBsAg < 1000 IU/mL who received the triple combination achieved functional cure. Even in patients who didn’t achieve functional cure, the combination of imdusiran and VTP-300 allowed more patients to remain off nucleoside analogue therapy compared to placebo. Data on AB-101 revealed that a 10mg once-daily dose was well-tolerated with high PD-L1 receptor occupancy and no liver dysfunction or immune-related adverse events. These findings represent significant progress in the pursuit of a functional cure for cHBV. The combination of imdusiran with immune-stimulating therapies holds promise for a larger segment of the cHBV population. The positive safety profile observed so far is crucial for long-term treatment success. Continued research and further clinical trials will be essential to confirm these findings and optimize treatment strategies. The development of AB-101 as a safe and effective oral PD-L1 inhibitor could further expand treatment options and potentially enhance combination therapies in the future.
Jon Napitupulu is Director of Media Relations at The Clinical Trial Vanguard. Jon, a computer data scientist, focuses on the latest clinical trial industry news and trends.
