June 22 (Reuters) - AbbVie ( ABBV ) said on Monday it would buy biotech Apogee Therapeutics ( APGE ) for $10.9 billion, in its largest buyout in more than five years as it looks to strengthen its next-gen immunology pipeline.

The acquisition, one of the largest biotech deals of the year, underscores the surge in pharmaceutical dealmaking, as companies race to build their portfolios ahead of looming patent expirations on blockbuster treatments.

AbbVie ( ABBV ) has offered $135.11 per Apogee share held, which implies a 49.49% premium to the stock's Thursday close.

Shares of Apogee surged 48% to $133.77 in premarket trading, while AbbVie ( ABBV ) was up 1.3%.

The acquisition gives AbbVie ( ABBV ) access to Apogee's lead drug candidate, zumilokibart, an experimental treatment targeting a range of inflammatory diseases including moderate-to-severe atopic dermatitis and asthma.

If approved, zumilokibart will fortify and complement AbbVie's ( ABBV ) immunology and inflammatory diseases portfolio, while also offering a potentially more convenient option to Sanofi and Regeneron's blockbuster Dupixent.

Unlike Dupixent, which is typically administered every two weeks in atopic dermatitis, zumilokibart is being studied as a subcutaneous injection given once every three or six months, likely offering a substantial reduction in dosing frequency.

AbbVie ( ABBV ) said the transaction is expected to close in the third quarter and add to its adjusted earnings per share in 2032.

(Reporting by Padmanabhan Ananthan in Bengaluru; Editing by Sriraj Kalluvila)