Enanta Advances RSV Antiviral Zelicapavir into Late-Stage Trials — Enanta Pharmaceuticals, Inc.

Event summary

Enanta Pharmaceuticals advances zelicapavir into a Phase 2b/3 registrational trial for high-risk adults with RSV, with topline data expected in 2027.
Pediatric Phase 2b trial for zelicapavir planned to start in Q3 2026, with topline data expected in 2027.
Zelicapavir targets a global RSV market opportunity of over $2 billion, with a potential total addressable population of over 3 million patients in the U.S.
Phase 2b/3 trial will evaluate zelicapavir in adults with risk factors such as COPD, CHF, or age 75+.

The big picture

Enanta's advancement of zelicapavir into late-stage trials positions it as a potential leader in the RSV antiviral space, addressing a significant unmet need in both adult and pediatric populations. The company's strategic focus on RSV follows its successful collaboration in hepatitis C, highlighting its ability to develop targeted viral therapies. The global RSV market represents a substantial opportunity, particularly as at-home diagnostics increase disease awareness and early intervention.

What we're watching

Clinical Success: Whether zelicapavir can demonstrate sufficient efficacy and safety in the Phase 2b/3 trial to support regulatory approval.
Market Potential: The pace at which Enanta can capture the estimated $2 billion global market for RSV antivirals.
Pediatric Development: How the pediatric Phase 2b trial will impact the broader adoption of zelicapavir in younger populations.