Health care stocks declined premarket Monday with the Health Care Select Sector SPDR Fund (XLV) 0.3% lower and the iShares Biotechnology ETF (IBB) down 0.9% recently.

Avidity Biosciences Inc (RNA) shares advanced by over 3% after the company said topline data from the phase 1/2 EXPLORE44 trial of del-zota to treat Duchenne muscular dystrophy showed "consistent, statistically significant improvements in dystrophin, exon skipping and creatine kinase."

Dyne Therapeutics (DYN) shares were up over 4% after the company said long-term clinical data from an ongoing phase 1/2 clinical trial of its investigational drug DYNE-251 is showing a "clinically meaningful and sustained functional improvement" in patients with Duchenne muscular dystrophy.

Novartis (NVS) is tracking the Trump administration's proposed reciprocal tariff policy "very carefully" and will respond accordingly once the policy is implemented next month, Reuters reported, citing Novartis Chief Executive Vas Narasimhan. Novartis shares were over 1% higher pre-bell.