Arbutus Biopharma slips after Europe revokes key patent

Roivant Sciences

16/01/2026 17:11

** Shares of Arbutus Biopharma ABUS.O fall 16% to $3.93

** The European Patent Office revoked Arbutus' key ’254 patent after challenges from Moderna MRNA.O and Merck MRK.N

** Arbutus says it disagrees with the outcome and plans to appeal once the written ruling is issued

** Arbutus says the decision is based on an EPO‑specific "added matter" rule and warns that outcomes in its broader litigation remain uncertain

** Jefferies analysts called the revocation "disappointing" and said overturning it on appeal will be "slightly tougher this time around"

** ABUS owns the ’254 patent, an LNP molar‑ratio patent for lipid nanoparticles

** Genevant, co-owned by Arbutus and drugmaker Roivant ROIV.O, asserts the patent in litigation

** The ruling affects some of Arbutus' and Genevant's patent cases against Moderna in Europe, but does not impact their lawsuits in the U.S., Japan, Canada, or Unified Patent Court cases not involving this patent

** ABUS rose 46% in 2025

 (Reporting by Kamal Choudhury in Bengaluru)

 ((Kamal.Choudhury@thomsonreuters.com;))