Health care stocks were mixed premarket Wednesday, with The Health Care Select Sector SPDR Fund (XLV) up 0.1% and the iShares Biotechnology ETF (IBB) 0.1% lower.

Bristol-Myers Squibb (BMY) said its monoclonal antibody BMS-986446 to treat early Alzheimer's disease has received fast track designation from the US Food and Drug Administration. Shares of Bristol-Myers Squibb were up more than 1% pre-bell.

Catalyst Pharmaceuticals (CPRX) stock was up more than 2% after the company said its board has approved a new share repurchase program to buy back up to $200 million of its common stock.

Halozyme Therapeutics (HALO) shares were up more than 2% after the company said it has agreed to acquire Elektrofi for an upfront payment of $750 million and up to three $50 million in milestone payments.