US drugmaker Pfizer reported first-quarter revenue that blew past analysts' average estimate, boosted by sales of its new treatments for cancer and its Hospira acquisition.

Shares of the company were up 3.2 per cent at $33.86 in premarket trading on Tuesday.

Pfizer also raised its revenue and earnings forecast for the year helped in part by a favorable impact of recent changes in foreign exchange rates.

The company's revenue rose 19.7 per cent to $13.01 billion, in the first quarter, ahead of analysts' estimate of $12.02 billion, according to the Thomson Reuters I/B/E/S.

Net income rose to $3.02 billion, or 49 cents per share, from $2.38 billion, or 38 cents per share, a year earlier.

Excluding items, the company earned 67 cents per share, above the average analyst estimate of 55 cents per share.

Pfizer and Allergan walked away from their $160 billion merger in April, citing new US Treasury rules aimed at blocking the deal's tax benefits.

The company said it now expects 2016 revenue to be in the range of $51 billion-$53 billion, up from $49 billion-$51 billion, and adjusted earnings of $2.38-$2.48 per share, up from $2.20-$2.30 per share. – Reuters