Healthcare stocks were mixed pre-bell Tuesday, with the State Street Health Care Select Sector SPDR ETF (XLV) up 0.5% and the iShares Biotechnology ETF (IBB) 0.7% lower.

Natera (NTRA) has received a Category 1 recommendation from the National Comprehensive Cancer Network for Signatera-guided adjuvant atezolizumab treatment in patients with muscle-invasive bladder cancer, the company said. Natera shares were down more than 2% premarket.

Boundless Bio (BOLD) stock was up more than 79% after the company said it signed a definitive merger agreement with privately held biotech firm Serapha Bio in an all-stock merger.

Armata Pharmaceuticals (ARMP) shares were up more than 10% after the company said it has received an additional $2.5 million in non-dilutive funding under a previously announced award from the Department of Defense.