60 Degrees Pharmaceuticals (SXTP) shares were 32% lower pre-bell Monday, adding to losses from the previous session.

Revolution Medicines (RVMD) stock was down 20% after The Wall Street Journal reported over the weekend that Merck (MRK) has dropped its bid to acquire the oncology company over a disagreement on price.

iOThree (IOTR) shares were 16% lower after Friday's 4.5% gain.