Shares of the Cambridge company surged $2.39, or 9 percent, to $27.75 in afternoon trading on the Nasdaq Stock Market.
The company lost $1.2 million, or 3 cents per share, compared with a loss of $21.6 million in the year-ago period. Revenue tripled to $22.2 million from $7.2 million in the prior year.
The results handily beat estimates of analysts polled by Thomson Financial, who expected a loss of 14 cents on revenue of $19.3 million.
Alnylam said its strong first-quarter results were due primarily to the company's partnership with Roche, which began in the third quarter of 2007 and gave the Swiss drug maker access to Alnylam's gene-silencing technology. Alnylam said it received $13.4 million in collaboration revenue during the quarter as part of the alliance.
The company also has partnerships with Novartis, Biogen Idec and the National Institutes of Health. (AP)