Isis Pharmaceuticals Inc. reported second quarter revenue of $57.1 million compared with $38.1 million in the previous quarter.

Isis (NASDAQ: ISIS) reported a net loss of $12.1 million for the quarter ended June 30, 2014, compared with $10 million for the like quarter last year.

Operating income went up to $1.1 million in the second quarter compared with a net operating loss of $21.5 million in the previous quarter. Isis’ operating income in the second quarter of 2014 was primarily driven by more than $40 million in milestone payments from partners.

Isis’ net loss increased in the first half of 2014 due to the planned increase in operating expenses associated with the company’s maturing pipeline of drugs, according to financial reports.