04:06 PM EDT, 10/07/2024 (MT Newswires) -- Pfizer ( PFE ) won a UK court decision to invalidate two patents supporting GSK's (GSK) vaccine for respiratory syncytial virus, Reuters reported Monday.

GSK told Reuters the ruling will have no impact on its ability to market its RSV vaccine globally, including the UK. The company plans to appeal the decision. Pfizer ( PFE ) welcomed the decision, Reuters reported.

Pfizer ( PFE ) shares advanced Monday after media report the company may become the target of a shareholder campaign led by activist Starboard Value, which has taken a $1 billion stake in the company. The shares were up 2% at market close.

GSK shares were marginally lower just ahead of close.

Neither Pfizer ( PFE ) nor GSK responded to MT Newswires seeking comment.

(Market Chatter news is derived from conversations with market professionals globally. This information is believed to be from reliable sources but may include rumor and speculation. Accuracy is not guaranteed.)