Keros Therapeutics (KROS) shares were down 72% pre-bell Thursday after the company said it voluntarily halted two treatment arms in a phase 2 study of cibotercept in combination with background therapy in patients with pulmonary arterial hypertension.
Samfine Creation (SFHG) stock was 36% lower, extending Wednesday's fall.
Intellinetics (INLX) shares were down 21% following a muted session.
Chatham Lodging Trust (CLDT) stock was 19% lower after closing nearly unchanged on Wednesday.
Myriad Genetics (MYGN) shares were down 17%, adding to Wednesday's losses.