Healthcare stocks declined late Thursday afternoon, with the NYSE Healthcare Index decreasing 0.9% and the State Street Health Care Select Sector SPDR ETF (XLV) shedding 1.4%.
The iShares Biotechnology ETF (IBB) fell 2.4%.
In corporate news, Moderna (MRNA) shares fell 22% following a 177% jump at the close of the previous trading session. The drugmaker and Merck (MRK) announced positive topline results from a late-stage trial of an experimental skin cancer treatment on Wednesday.