Shares of GSK Plc. were gaining around 6 percent on the London Stock Exchange, as well as in the pre-market activity on the NYSE,

GSK launched a 2 billion pounds ($2.5 billion) share buyback on Wednesday and lifted its long-term sales target to nearly $50 billion, betting that growing sales of its HIV and cancer drugs will make up for pressures on its vaccines revenue.

GSK launched a rare £2bn share buyback and raised its growth targets on the back of strong sales of speciality medicines including cancer and HIV drugs, sending shares up as much as 6 per cent on Wednesday.