Dublin, Ireland-based branded pharmaceuticals firm Shire (NASDAQ:SHPG) has bought privately owned Swedish biotech Premacure for an undisclosed sum, as Shire confirmed Tuesday.

Premacure currently has a protein replacement therapy in phase 2 development, aimed at preventing a rare and potentially blinding eye disorder that can affect premature infants, known as retinopathy of prematurity (ROP). According to Shire, ROP afflicts as many as 14,000 to 16,000 preterm infants in the U.S. annually, with just under 10% of these patients requiring medical treatment.

Shire will pay an unspecified sum up front for Premacure, followed by later milestone payments as Premacure's treatment progresses toward commercial sale. In acquiring Premacure, Shire says it's entering a new therapeutic area -- neonatology -- and the company intends to continue Premacure's work, adding the company's new "investigational protein" to its pipeline of other drugs in development.

Investors reacted to news of the acquisition by bidding Shire shares up 0.2%. Shares closed at $91.56 Tuesday.