Pfizer, the largest U.S. drugmaker, reported a bigger-than-expected quarterly profit, helped by higher sales of breast cancer drug Ibrance and pain relief drug Lyrica.

Ibrance, which is expected to face competition from rival Novartis' recently approved treatment Kisqali, generated sales of $679 million, a 58.3 percent rise from the year-ago quarter. The consensus estimate for Ibrance sales was $682 million, according to Barclays.

U.S. sales of Lyrica rose 14 percent to $891 million, compared with the consensus estimate of $829 million according to Barclays.

Pfizer, which closed its $14 billion acquisition of Medivation in September, said net profit rose to $3.12 billion, or 51 cents per share, in the first quarter, from $3.04 billion, or 49 cents per share, a year earlier.

Excluding items, the company earned 69 cents per share, beating the average analyst estimate of 67 cents, according to Thomson Reuters I/B/E/S.

Revenue fell 1.7 percent to $12.78 billion, below the average estimate of $13.09 billion.