09:19 AM EDT, 09/29/2025 (MT Newswires) -- Health care stocks were rising premarket Monday, with the iShares Biotechnology ETF (IBB) 0.7% higher and the Health Care Select Sector SPDR Fund ( XLV ) up 0.2%.

Genmab ( GMAB ) has agreed to acquire biotechnology firm Merus (MRUS) in an all-cash deal worth about $8 billion, the companies said in a joint statement. Merus shares were up more than 37% and Genmab ( GMAB ) shares were down more than 2% premarket.

GSK (GSK) said it has appointed Luke Miels chief executive officer designate. GSK stock was up more than 2% pre-bell.

MoonLake Immunotherapeutics ( MLTX ) said its experimental drug, sonelokimab, met the primary and key secondary endpoints in two Phase 3 trials for moderate-to-severe hidradenitis suppurativa, a chronic inflammatory skin disease. However, late-stage clinical trial data showed that a rival treatment from UCB is superior, Bloomberg reported, citing an analyst. Shares of MoonLake Immunotherapeutics ( MLTX ) were down more than 87% premarket.