Buoyed by a surge in sales of its migraine drug and upfront payments for another drug in development, pharmaceutical firm (Nasdaq: POZN) beat Wall Street estimates with a smaller than predicted loss for the first quarter.

Pozen reported Thursday a loss of $3.5 million, or 12 cents a share, which was 6 cents smaller than analysts had projected. The loss also was less than half the $7.4 million Pozen lost in the same quarter a year ago.

Revenues increased $1 million from 2008 to $8.8 million. Drivers included $1 million in royalties from its migraine drug sold in partnership with GlaxoSmithKline and $3.1 million in upfront payments from AstraZeneca for a compound in clinical trial. Pozen also received $4.7 million from AstraZeneca for development work.

Expenses, meanwhile, fell to $12.5 million from $16 million a year earlier due to smaller research and development expense.

Sales of Treximet, the migraine drug, increased 14 percent in the first quarter from the previous month to $20.3 million, Pozen said. Treximet was approved by the FDA last year.

Through the quarter, Treximet prescriptions jumped 27 percent in March from February, the company added, citing a promotion launched by GSK.

Pozen and AstraZeneca expect to submit a new drug application for its arthritis pain reliever called PN 400. If the Food and Drug Administration accepts the NDA, AstraZeneca would pay Pozen a $10 million milestone payment.