Amarin Corp. plc, which has research headquarters in Groton, reported a first-quarter loss of $88.3 million compared with an $18.3 million profit for the same period last year.
The loss was a little more than analysts expected.
But company president Joseph Zakrzewski pointed out that the quarter's milestones included the issuance of $150 million in exchangeable senior notes and approval of one of its major patent applications.
"The first quarter was very positive for Amarin," he said in a statement.
Zakrzewski said Amarin's lead drug candidate is on schedule for regulatory approval in July and launch in the first quarter of 2013.