The Delaware Supreme Court on Friday upheld a landmark Chancery Court decision allowing Fresenius SE & Co. to walk away from its $4.3 billion deal to buy generic drugmaker Akorn Inc. based on a “material adverse change” in Akorn’s business.

The ruling was a win for Fresenius’ Paul, Weiss, Rifkind, Wharton & Garrison attorneys, who had argued that a raft of regulatory issues at Akorn had justified their client’s decision to scrap the merger.