Abbott Laboratories ( ABT) beat Wall Street's first-quarter earnings estimate Wednesday although sales for a key rheumatoid arthritis drug didn't meet the company's projections. The maker of diagnostics, medical devices and drugs reported net income for the first quarter of $1.44 billion, or 92 cents a share, compared with net income of $938 million, or 60 cents a share, in the year-ago quarter. Excluding special items, Abbott reported a 16% increase in earnings to 73 cents a share in the first quarter, 3 cents better than the Street's consensus estimate. First-quarter revenue totaled $6.71 billion, below the consensus analyst forecast of $7.06 billion. Abbott reported revenue of $6.76 billion in the year-ago quarter. Of most interest to investors, sales of Abbott's rheumatoid arthritis drug Humira rose 17% to $1.02 billion in the first quarter. U.S. sales of Humira rose 2% in the quarter, while international sales increased 29%. Humira, which also is used to treat psoriasis and other related diseases, is Abbott's top-selling and most important drug, contributing 15% of the company's total revenue last year. Abbott executives promised at least 25% sales growth from Humira this year, but prescription trends to date have lagged behind that forecast, raising investor concerns and weighing on the stock. Overall, worldwide pharmaceutical sales decreased 6% to $3.64 billion, affected in part by negative currency trends. Worldwide nutritional sales rose 6.4%, while diagnostics sales fell 1.8% in the first quarter. Abbott forecast second-quarter adjusted earnings in the range of 87 cents to 89 cents a share, in line with current consensus of 88 cents a share. Abbott shares closed Tuesday at $44.71.