Health-care companies fell as euphoria about a breakthrough in RNA-based medicine faded.

Moderna shed almost one quarter of its value, giving back a chunk of the gains associated with Wednesday's disclosure of promising data on a cancer treatment. Moderna and Merck's jointly developed personalized cancer vaccine had stopped melanoma cancer from coming back or spreading in patients. The personalized nature of the vaccine and the relatively low occurrence of the melanoma strain of skin cancer could limit commercial potential.

For 2027, employers may be facing the biggest health-insurance increase in at least two decades.