LONDON — Anglo-Swedish pharmaceutical company AstraZeneca PLC yesterday reported that first-quarter profit rose by 29 percent, but cautioned that comparisons will be tougher in the second half of the year when a key patent expires.

For the three months ending March 31, AstraZeneca said net profit was $2.9 billion, compared with $2.3 billion in the same period a year ago. Revenue rose 11 percent to $8.6 billion, a seven percent increase on a constant exchange rates basis.

The strong performance was led by a 27 percent increase in sales of Crestor, its cardiovascular drug; a 29 percent gain for the asthma drug Symbicort, and a 13 percent rise for the anti-psychotic drug Seroquel.

The company raised its full-year guidance to earnings of between $6.05 and $6.35 per share, up from the previous range of $5.90 to $6.30. In the first quarter, AstraZeneca earned $2.03 per share.

AstraZeneca shares were up 2.2 percent to 2,900 pence on the London Stock Exchange by late afternoon, retreating from a peak of 2,944 pence just after the release of the report.

"The share price is likely to respond positively to a strong set of quarterly results and raised full year Core EPS guidance," said Jeremy Batstone-Carr, analyst at Charles Stanley & Co.