Chief Executive Andrew Witty said the core areas made up 70 percent of the business and it was accelerating a review of its established product portfolio that made up about half of the rest.

"You should not be surprised if we were able to transact a disposal of some of that established product portfolio in the next year or two," he told reporters on a conference call. "That is not part of our future."

The British company announced a multi-part deal on Monday that sees GlaxoSmithKline take the lead in running a consumer health business with Novartis, while selling its oncology unit to the Swiss company.

Witty said he continued to rule out traditional large-scale M&A deals, in which large drugs company are bolted together, instead favoring other tie-ups that focused on areas in which GlaxoSmithKline could be a leading player.

(Reporting by Paul Sandle, Editing by Belinda Goldsmith)

Stocks treated in this article : Novartis AG, GlaxoSmithKline plc