Health care stocks declined pre-bell Monday as the Health Care Select Sector SPDR Fund (XLV) was 0.2% lower and the iShares Biotechnology ETF (IBB) was down 0.8% recently.

Teva Pharmaceutical (TEVA) and Alvotech (ALVO) said Selarsdi has been approved by the US Food and Drug administration as interchangeable with the reference biologic Stelara. Teva Pharmaceutical shares were up over 5% and Alvotech shares were over 2% higher premarket.

Axsome Therapeutics (AXSM) shares advanced by over 4% after the company reported a narrower Q1 net loss as revenue increased.

PTC Therapeutics (PTCT) said a phase 2 study of PTC518, or votoplam, in stage 2 and 3 Huntington's disease met its primary endpoint of reduction in blood Huntingtin protein levels at week 12. Shares of PTC Therapeutics fell by 22% premarket.