Health care stocks were mixed premarket Monday, with the Health Care Select Sector SPDR Fund (XLV) declining by 0.1% and the iShares Biotechnology ETF (IBB) up 0.9%.

Avidity Biosciences (RNA) agreed to be acquired by Novartis (NVS) for $72 per share in a deal that values Avidity at about $12 billion, the companies said. Shares of Novartis were down more than 1% and Avidity Biosciences stock was up more than 43% pre-bell.

Revvity (RVTY) shares were 3% lower after the company reported a year over year decline in Q3 adjusted earnings from continuing operations.

BridgeBio Pharma (BBIO) stock was up 5% after the company said its phase 3 study of investigational oral therapy BBP-418 in patients with limb-girdle muscular dystrophy type 2I/R9 showed "clinically meaningful improvements" in motor and pulmonary function.