This section highlights FDA-related milestones and regulatory updates for drugs developed by Arbutus Biopharma (ABUS).
Over the past two years, Arbutus Biopharma has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
AB-101 and Imdusiran. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
AB-101 FDA Regulatory Timeline and Events
AB-101 is a drug developed by Arbutus Biopharma for the following indication: Oral PD-L1 inhibitor.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- AB-101
- Announced Date:
- October 22, 2026
- Indication:
- Oral PD-L1 inhibitor
Announcement
Arbutus Biopharma announced that the Company was notified by the U.S. Food and Drug Administration ("FDA") that the clinical hold on the Investigational New Drug ("IND") application for AB-101 has been removed and that the Company may engage in additional clinical development for AB-101 in the United States. Arbutus is evaluating next steps for the continued development of AB-101.
Read Announcement- Drug:
- AB-101
- Announced Date:
- October 16, 2025
- Indication:
- Oral PD-L1 inhibitor
Announcement
Artiva Biotherapeutics, Inc. announced today that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to AlloNK® (also known as AB-101) for the treatment of refractory rheumatoid arthritis (RA) in combination with rituximab and that the Company has prioritized refractory RA as the program's lead indication.
AI Summary
Artiva Biotherapeutics, a clinical-stage biotech, announced that the U.S. Food and Drug Administration has granted Fast Track Designation to AlloNK® (AB-101) for the treatment of refractory rheumatoid arthritis (RA) in combination with rituximab. The company has chosen refractory RA as its lead indication, marking AlloNK as the first deep B-cell depleting therapy in this category to earn Fast Track status.
To date, more than 20 patients have been treated with AlloNK plus monoclonal antibody therapy across company-sponsored and investigator-initiated trials. Upcoming translational data, expected in mid-November, should demonstrate consistent, deep B-cell depletion that supports AlloNK’s mechanism of action.
Safety data to be released concurrently will highlight the regimen’s favorable tolerability and its feasibility in outpatient rheumatology clinics, including the use of cyclophosphamide/fludarabine conditioning. Clinical response results from over 15 refractory RA patients—with some followed for at least six months—are anticipated in the first half of 2026.
Artiva plans FDA interactions in early 2026 to align on a pivotal trial design, potentially positioning AlloNK as the first deep B-cell depleting therapy to advance to a late‐stage RA study.
Read Announcement- Drug:
- AB-101
- Announced Date:
- October 7, 2025
- Indication:
- Oral PD-L1 inhibitor
Announcement
Arbutus Biopharma announced that three abstracts featuring imdusiran data and one abstract featuring AB-101 data, have been accepted for poster presentations at the American Association for the Study of Liver Diseases ("AASLD") – The Liver Meeting 2025, taking place November 7–11 in Washington, DC. Notably, the AB-101 abstract has been selected as a Poster of Distinction.
AI Summary
Arbutus Biopharma announced that three abstracts featuring imdusiran data and one abstract featuring AB-101 data have been accepted for poster presentations at the American Association for the Study of Liver Diseases (AASLD) – The Liver Meeting 2025, November 7–11 in Washington, D.C. Notably, the AB-101 abstract was selected as a Poster of Distinction.
The three imdusiran posters cover: an integrated safety analysis showing that repeat dosing of 60 mg and 90 mg every eight weeks was safe and well-tolerated in chronic hepatitis B patients; enhanced hepatitis B surface antigen (HBsAg) response when imdusiran was combined with pegylated interferon alfa-2a, especially in genotypes B and C; and elevated soluble immune biomarkers in subjects who lost HBsAg after imdusiran plus immunotherapy, suggesting stronger immune activation in certain study cohorts.
The Poster of Distinction on AB-101 details the safety, tolerability, pharmacokinetics and pharmacodynamics of multiple oral doses up to 30 mg once daily, with dose-related increases in PD-L1 receptor occupancy. All posters will be available on the AASLD website and on Arbutus’s Publications page beginning November 7, 2025.
Read Announcement- Drug:
- AB-101
- Announced Date:
- May 7, 2025
- Indication:
- Oral PD-L1 inhibitor
Announcement
Arbutus Biopharma Corporation announced the presentation of five posters, including one late-breaker, highlighting imdusiran, its RNAi therapeutic and AB-101, its oral PD-L1 inhibitor, at the European Association for the Study of the Liver (EASL) Congress 2025.
AI Summary
At the 2025 European Association for the Study of the Liver (EASL) Congress, Arbutus Biopharma Corporation presented five posters, including one late-breaker poster showcasing important new data. The late-breaker focused on imdusiran, an RNA interference (RNAi) therapeutic, used in combination with VTP-300 and low dose nivolumab. This study showed promising results, with several chronic hepatitis B patients achieving a functional cure, marked by significant reductions in hepatitis B surface antigen levels.
In addition, Arbutus presented pre-clinical and clinical data on AB-101, its oral PD-L1 inhibitor. Early findings from its Phase 1a/1b trial report that AB-101 is safe, well-tolerated, and achieves high receptor occupancy without causing liver dysfunction. These encouraging results support further clinical studies to confirm the potential of imdusiran and AB-101 in treating chronic hepatitis B.
Read Announcement- Drug:
- AB-101
- Announced Date:
- April 23, 2025
- Indication:
- Oral PD-L1 inhibitor
Announcement
Arbutus Biopharma Corporation announced that five abstracts, including one late-breaker, have been accepted for presentation at the European Association for the Study of the Liver (EASL) Congress 2025 taking place May 7 - 10, 2025 in Amsterdam, Netherlands.
AI Summary
Arbutus Biopharma Corporation announced that five abstracts, including one late-breaker, have been accepted for poster presentations at the upcoming European Association for the Study of the Liver (EASL) Congress 2025. The event will take place between May 7 and 10, 2025, in Amsterdam, Netherlands, where the posters will be featured in the Viral Hepatitis B and D session. The abstracts highlight new therapies under evaluation for chronic hepatitis B, including results from trials combining imdusiran with pegylated interferon alfa-2a and nucleos(t)ide analogue therapy, as well as studies showcasing the profiles of a novel PD-L1 inhibitor, AB-101.
This acceptance at a major European conference underscores Arbutus’ commitment to advancing research in viral hepatitis and presents potential insights into treatments that could lead to a functional cure for patients with chronic hepatitis B.
Read Announcement- Drug:
- AB-101
- Announced Date:
- March 24, 2025
- Indication:
- Oral PD-L1 inhibitor
Announcement
Artiva Biotherapeutics, announced Recent Business Highlightsnc.
AI Summary
Artiva Biotherapeutics recently highlighted key business updates in its press release. The company showcased significant progress in its AlloNK® program for autoimmune diseases. Initial data from their autoimmune trial are expected in the first half of 2025, while updated clinical data from the Phase 1/2 NHL trial combining AlloNK® with rituximab will be presented at a medical conference later in 2025. These data point to deep B-cell depletion and durable responses with the treatment regimen suitable for outpatient administration.
Additionally, Artiva strengthened its leadership team by appointing experts in cell therapy and autoimmunity, including a new independent board member, Dr. Dan Baker. With a robust cash position of $185.4 million at the end of 2024, the company’s finances are expected to support operations through at least the end of 2026 as it advances its cell therapy pipeline.
Read Announcement
Imdusiran FDA Regulatory Events
Imdusiran is a drug developed by Arbutus Biopharma for the following indication: For chronic hepatitis B virus.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- Imdusiran
- Announced Date:
- April 15, 2026
- Indication:
- For chronic hepatitis B virus
Announcement
Arbutus Biopharma Corporation announced that the U.S. Food and Drug Administration ("FDA") has granted Fast Track designation for imdusiran for the treatment of chronic hepatitis B ("cHBV").
AI Summary
Arbutus Biopharma announced that the U.S. Food and Drug Administration granted Fast Track designation to imdusiran for the treatment of chronic hepatitis B (cHBV). Fast Track is meant to help speed the development and review of drugs for serious conditions that address unmet medical needs. The designation can allow more frequent communication with the FDA and the option of rolling submission of data, which may shorten the time the agency needs to evaluate a marketing application.
Imdusiran (AB-729) is an investigational RNA interference therapy designed to lower hepatitis B virus activity and viral proteins, aiming to improve immune control of the infection. With Fast Track status, Arbutus may be able to move clinical studies and regulatory steps more efficiently, potentially bringing a new treatment option to people with chronic hepatitis B sooner if clinical trials are successful.
Read Announcement- Drug:
- Imdusiran
- Announced Date:
- January 13, 2025
- Indication:
- For chronic hepatitis B virus
Announcement
Arbutus Biopharma announced its 2025 corporate objectives and provided a financial update.
AI Summary
Arbutus Biopharma announced its 2025 corporate objectives along with a financial update focused on advancing its efforts to cure chronic hepatitis B. Following promising data from an earlier Phase 2a trial using its RNAi therapeutic imdusiran combined with interferon and nucleos(t)ide analogue therapy, the company plans to initiate a placebo-controlled Phase 2b trial in the first half of 2025. This trial, pending regulatory approval, will enroll about 170 patients to further evaluate the treatment’s potential.
Financially, Arbutus is on solid ground with approximately $123 million in cash, cash equivalents, and marketable securities. The firm expects to lower its net cash burn to $47–$50 million in 2025—down from around $65 million in 2024—which, along with anticipated milestones, should fund its operations through early 2028.
Read Announcement
