Sector Update: Healthcare Stocks Fall Premarket Friday

09:14 AM EDT, 10/23/2026 (MT Newswires) -- Healthcare stocks were falling premarket Friday, with the State Street Health Care Select Sector SPDR ETF (XLV) 0.5% lower and the iShares Biotechnology ETF (IBB) down 0.7%. Moderna (MRNA) and Merck (MRK) shares declined after reports emerged about a possible leak of data on the companies' highly anticipated personalized melanoma vaccine, Bloomberg reported Thursday, citing unverified sources on X. Shares of Moderna were still down more than 4% pre-bell. Zai Lab (ZLAB) stock was up more than 7% after the company said its experimental drug zocilurtatug pelitecan, combined with atezolizumab, achieved an 81.8% objective response rate in a phase 1 trial in patients with extensive-stage small cell lung cancer. Zymeworks (ZYME) shares were up more than 2% after the company said it signed an exclusive global license and collaboration agreement with Roche for ZW209, a cancer drug targeting the DLL3 protein, with potential milestone payments of up to $718 million.