A UK pharmaceutical industry watchdog has ruled that Sanofi breached the country’s code of practice by making misleading claims about its respiratory syncytial virus (RSV) therapy in comparison with a rival product from Pfizer. The decision was issued by the Prescription Medicines Code of Practice Authority (PMCPA) following a complaint lodged by Pfizer.

The case relates to public comments made by Sanofi’s chief executive, who suggested that Sanofi’s RSV antibody treatment, Beyfortus, offered advantages over Pfizer’s RSV vaccine, Abrysvo. The PMCPA concluded that the remarks amounted to promotional and comparative claims that were not supported by direct clinical evidence.

According to the ruling, the statements were unbalanced and had the potential to mislead, as there is currently no head-to-head clinical data demonstrating superiority of one product over the other. The watchdog also noted that the comments could undermine public confidence in the pharmaceutical industry by blurring the line between factual information and promotion.

Sanofi said it accepts the findings and reiterated its commitment to maintaining high ethical standards in its communications. Pfizer had argued that the comments unfairly promoted Beyfortus and indirectly discredited its own RSV vaccine.

Beyfortus is designed to protect infants directly from RSV, while Abrysvo is administered to pregnant women to help protect newborns through maternal immunisation. Both products address RSV, a common but potentially serious respiratory infection, particularly in infants and older adults. The ruling highlights the strict limits placed on comparative claims in the promotion of prescription medicines in the UK.