Drug giant

Pfizer

(PFE) - Get Report

said it agreed to buy

Vicuron Pharmaceuticals

(MICU)

, a biopharmaceutical company focused on developing anti-infectives, for $1.9 billion.

Under the merger agreement, Pfizer will acquire Vicuron for $29.10 a share. Pfizer said the price represents a 74% premium over Vicuron's 90-day average closing share price. Vicuron closed Wednesday at $15.80 and was up $12.10, or 77%, to $27.90 in premarket trading.

Vicuron, based in King of Prussia, Pa., has two products currently under review at the Food and Drug Administration: anidulafungin for fungal infections and dalbavancin for Gram-positive infections.

Pfizer expects to close the acquisition in the third quarter. The company's shares were down 23 cents to $28.20 in trading before the opening bell.