From RBC: "the U.S. regulatory path currently emphasizes demonstration of outcomes benefits (hospitalization, mortality, etc.) and this would be difficult to show in the current environment, barring a major mutation."
ENTA would only have to show non-inferiority to Paxlovid in high risk groups for hospitalization and or death. It isn't clear to me why a drug that reduces symptoms in a regular risk group cannot be approved. A major new mutation could make vaccines less effective and increase the need for new anti-Covid drugs.