British drugmaker AstraZeneca on Thursday said annual earnings were set to rise more than expected after a strong third quarter.

Net profit more than tripled to $770 million (710 million euros) in the three months to the end of September compared with one year earlier, AstraZeneca said in a statement.

"Our financial performance in the year to date... underpinned today's upgrade to full-year guidance," said chief executive Pascal Soriot.

"2016 will be a pivotal year in our strategic journey as we face the impact of loss of exclusivity to (anti-cholesterol drug) Crestor in the US."

AstraZeneca said it now expects "a mid to high single-digit percent increase" in annual core earnings per share compared with "a low single-digit percent increase".