Health care stocks were lower Tuesday afternoon, with the NYSE Health Care Index falling 2.6% and the Health Care Select Sector SPDR Fund (XLV) dropping 2.3%.

The iShares Biotechnology ETF (IBB) shed 1.5%.

In corporate news, UnitedHealth (UNH) suspended its full-year outlook amid higher-than-expected medical costs, while Andrew Witty stepped down as chief executive due to "personal reasons." UnitedHealth shares fell more than 16%.

Alumis (ALMS) shares fell past 8%. Shareholders of Alumis and

Acelyrin (SLRN) separately approved their merger deal at special meetings. Acelyrin shares also fell over 9%.

CNS Pharmaceuticals (CNSP) shares jumped 35% after the company said it has acquired from Cortice Biosciences an orphan drug designation for late-stage abeotaxane TPI 287 as a potential treatment for glioblastoma multiforme.