Merck's RSV Antibody Faces Major Challenges vs. Sanofi's Beyfortus Exhibiting 83% Efficacy in Reducing Hospitalization

While Merck & Co. 's infant respiratory syncytial virus (RSV) antibody clesrovimab is nearing approval, sanofi also won approval last year for its RSV prevention drug beyforts in partnership with astrazeneca. This news undoubtedly brings new hope to the global healthcare industry, especially in the field of RSV vaccines.

"We would very much welcome having more participants on board because it increases the scale of the competition," Thomas Triomphe, Sanofi's executive vice president for vaccines, said of the upcoming RSV competition during an analyst call on Friday. He stressed that more players mean more innovation and better healthcare solutions, which is good for the industry as a whole and for patients.

Triomphe noted that Merck still has more data on clesrovimab after announcing phase 2b/3 clinical results last week. In the meantime, Sanofi remains "very confident" in the Beyfortus numbers it has released so far, he said. He mentioned that the protection data provided by Beyfortus in six months is very encouraging, as the effect has not diminished.

"After six months, we were still seeing 83 percent hospitalization efficacy," he said, adding that he believed "the duration of protection from Beyfortus was significantly more favorable compared to clesrovimab." This data suggests that Beyfortus has a significant advantage in preventing RSV infection.

In Merck's infant RSV study, clesrovimab successfully reduced RSV-related hospitalizations and RSV-related lower respiratory tract infection hospitalizations by 84 percent and 91 percent, respectively, over five months compared to placebo. This result is impressive and shows the great potential of clesrovimab in preventing RSV infection.

At the trial's primary endpoint, clesrovimab reduced the incidence of RSV-related medical lower respiratory tract infections by 60 percent compared to placebo. This data provides further evidence of the effectiveness of clesrovimab in preventing RSV infection.

Sanofi Chief Financial Officer franois-xavier Roger noted in a conference call on Friday that the inherent uncertainty of cross-trial comparisons suggested that existing Beyfortus data showed a reduction of about 75 percent in the incidence of lower respiratory tract infections with clesrovimab compared to 60 percent with Clesrovimab. This data further reinforces Beyfortus' advantage in preventing RSV infection.

And, whether or not Merck brings clesrovimab into the 2025-2026 RSV season as planned, "2025 will be a year of growth for Beyfortus," the CFO stressed. He is confident that Beyfortus' sales will grow significantly as it gradually gains market share.

Since it was approved last July, Beyfortus has gradually built up its sales profile. In the third quarter of 2024, sales of this preventive antibody reached 645 million euros ($699), an increase of 382% compared to the same period in 2023. Overall, sales of the drug have reached 845 million euros since the beginning of the year, which is close to the best-selling threshold.

Sanofi said at the time that Beyfortus quickly fell into a supply crunch shortly after going public last year due to "higher than expected demand." To counter this, Sanofi and its partner Astrazeneca have moved quickly to ensure there is no repeat of the supply crunch in 2024. Recently they added a new filling line and shipped antibody doses ahead of the 2024 RSV season.

"There are 20 markets and we don't see any capacity constraints," Triumph said on Sanofi's conference call. "We will increase supply next year and the year after to make sure there are no supply constraints." This initiative demonstrates Sanofi's confidence in the future of Beyfortus and its commitment to meeting the needs of the global market.

The comments by Sanofi executives came as the French pharmaceutical company reported a 15.7 per cent rise in third-quarter sales. This growth was mainly driven by the excellent performance of its immunology product Dupixent, which brought in sales of nearly 3.5 billion euros (about $3.8 billion), an increase of about 24 percent over the third quarter of 2023. Sanofi confirmed DuPont's full-year sales target of about 13 billion euros.

Elsewhere, newly launched drugs rose 67.1 percent to 727 million euros ($787), led by hemophilia drug Altuviiio, Pompeii disease treatment Nexviazyme and Rezurock for graft-versus-host disease. The strong performance of these new drugs further strengthens Sanofi's position in the field of innovative medicines.

Meanwhile, Sanofi's consumer health division, Opella, saw revenue rise 7.9 percent. This growth shows that Sanofi is also making significant progress in consumer health.

Earlier this week, Sanofi confirmed it had entered exclusive talks with U.S. private equity firm Clayton, Dubilier & Rice to sell a controlling 50 percent stake in its consumer healthcare business, which is valued at around 16 billion euros. This move will further strengthen Sanofi's financial strength and provide additional financial support for its future expansion.