LONDON (Reuters) - Shareholders in British drugmaker GlaxoSmithKline (>> GlaxoSmithKline plc) have approved a planned deal with Switzerland's Novartis (>> Novartis AG), which will see the two pharmaceutical groups trade more than $20 billion (12.7 billion pounds) of assets.

GSK said a meeting on Thursday had approved the transaction by an overwhelming majority and the deal was on track to complete in the first half of 2015.

The transaction, which includes GSK buying Novartis' vaccines business, Novartis purchasing GSK's cancer drugs, and the two groups tying up in consumer healthcare, was first unveiled in April.

U.S. antitrust regulators approved the deal in November, after Novartis agreed to divest its nicotine patch Habitrol, while European Union antitrust regulators will decide by Jan. 14 whether to clear the arrangement.

(Reporting by Ben Hirschler; Editing by Martinne Geller)

Stocks treated in this article : Novartis AG, GlaxoSmithKline plc