AstraZeneca’s Beyfortus Reaches €1.8 Billion Sales as Enflonsia Falters
AstraZeneca/Sanofi’s RSV antibody Beyfortus generated €1.8 billion in sales during 2025, marking a 9.5% year-over-year increase and highlighting robust demand. Merck’s Enflonsia saw sales slump to $21 million in the fourth quarter from $79 million in Q3, underscoring competitive challenges in the RSV market.
1. Beyfortus 2025 Performance
AstraZeneca/Sanofi’s RSV antibody Beyfortus achieved €1.8 billion in 2025 sales, up 9.5% year-over-year. Strong uptake in key regions drove this growth, positioning Beyfortus as a leading RSV prophylactic.
2. Enflonsia Sales Decline
Merck’s Enflonsia recorded $21 million in fourth-quarter sales, down from $79 million in Q3. Lower infant immunization rates and elevated channel inventories contributed to the sharp downturn.
3. Intensifying RSV Competition
Several RSV preventive products, including Pfizer’s Abrysvo, GSK’s Arexvy and Moderna’s mRESVIA, have received US approval. This broadens the competitive field and raises market share pressure for existing players.
4. Implications for AstraZeneca
Robust Beyfortus growth could enable AstraZeneca to expand its RSV franchise, but sustained investment in production and market access will be crucial to fend off new entrants and logistics challenges.