Sanofi (SNY) has been found by UK's Prescription Medicines Code of Practice Authority in breach of the Association of the British Pharmaceutical Industry code of practice for allegedly making "misleading" claims about its Beyfortus drug and disparaging Pfizer's (PFE) rival vaccine, the regulator said Monday.

Sanofi's action "brought discredit upon and reduced confidence" in the pharmaceutical industry, according to the regulator.

The case stemmed from Pfizer's complaint about an article in a UK Sunday newspaper that contained comments by a Sanofi executive claiming Beyfortus is superior.

Beyfortus is a monoclonal antibody for the prevention of respiratory syncytial virus, or RSV, in infants. Pfizer's Abrysvo vaccine is being used in the UK's maternal vaccination program to help protect newborns and infants from RSV, the regulator said in its case report.

Sanofi did not immediately reply to a request for comment from MT Newswires.