Feb. 4 at 3:29 PM
$ABUS - Long and strong.
$MRNA faces a huge payout soon.
The judge didn’t bar the doctrine of equivalents (DOE) because DOE is disfavored in general—he barred it because Arbutus and Genevant legally gave up that territory during patent prosecution, and U.S. law does not allow them to reclaim it later.
Here’s the precise, judge-level explanation, grounded in patent doctrine and what happened in this case.
The core reason: prosecution history estoppel
In Arbutus Biopharma / Genevant Sciences v. Moderna, the court barred DOE for the molar-ratio claims because of prosecution history estoppel.
What that means in plain terms
During patent prosecution, Arbutus narrowed its claims to overcome prior art by removing flexibility from numerical ranges (e.g., removing the word “about” from lipid molar ratios).
Under Supreme Court and Federal Circuit precedent:
If you narrow a claim to get your patent, you can’t later expand it via DOE to cover what you surrendered.
