09:27 AM EST, 11/13/2025 (MT Newswires) -- Health care stocks were declining premarket Thursday with the Health Care Select Sector SPDR Fund ( XLV ) and Shares Biotechnology ETF (IBB) 0.2% lower.

Day One Biopharmaceuticals ( DAWN ) shares were down more than 17% after the company said it has agreed to acquire Mersana Therapeutics ( MRSN ) in a transaction valued at up to about $285 million. Mersana Therapeutics ( MRSN ) stock was up more than 208% pre-bell.

BrainsWay ( BWAY ) stock was up more than 5% after the company said it received US Food and Drug Administration clearance to offer its deep transcranial magnetic stimulation as an add-on treatment for major depressive disorder in patients aged 15 to 21.

Eli Lilly ( LLY ) and Novo Nordisk ( NVO ) have entered into a partnership with Mangoceuticals ( MGRX ) to launch two integrated programs that provide direct access to the two firms' GLP-1 medications, Mangoceuticals ( MGRX ) said. Shares of Mangoceuticals ( MGRX ) were up more than 21% premarket.