The European Commission has launched a formal antitrust investigation into Sanofi (NASDAQ: SNY) to determine whether the French drugmaker violated EU competition rules through a communication campaign targeting a competing influenza vaccine.
The probe centers on allegations that Sanofi disseminated misleading information about Fluad, an enhanced flu vaccine marketed by CSL Seqirus (OTC: CSLLY), while promoting its own vaccine, Efluelda, in Germany and France.
The latest action follows unannounced inspections conducted at Sanofi's premises in September 2025.
Sanofi Responds To EU Investigation
After publication, Sanofi told Benzinga that the European Commission's formal proceedings relate to alleged anticompetitive conduct involving its high-dose influenza vaccine in Germany and France. The company said the probe stems from issues the Commission raised during inspections of the vaccines sector in September 2025.
Sanofi said the opening of formal proceedings is a procedural step and does not prejudge the outcome of the investigation. The company noted that the Commission has not established any infringement of competition law at this stage and said the regulator's Preliminary Assessment allows Sanofi to address the Commission's concerns through commitments if it chooses to do so.
The company added that it is confident it has acted, and continues to act, in full compliance with applicable laws and regulations, including competition law, and said it is cooperating fully with the Commission throughout the investigation.
Commission Raises Concerns Over Messaging Campaign
According to the Commission, Sanofi may have portrayed Fluad as inferior to Efluelda despite recommendations from health authorities supporting the rival vaccine for vulnerable patients with risk factors.
The investigation focuses primarily on communications directed at healthcare professionals in Germany and France, markets where the Commission preliminarily believes Sanofi holds a dominant position.
Regulators are examining several aspects of Sanofi's messaging, including claims that the scientific evidence supporting Fluad was weaker than that underpinning Efluelda.
Officials are also reviewing whether Sanofi provided misleading or inaccurate interpretations of national vaccination recommendations.
In Germany, the Commission is further scrutinizing claims suggesting that recommendations supporting Fluad remained subject to unresolved scientific objections from medical professional societies.
Potential Violation Of EU Competition Rules
If the allegations are substantiated, the conduct could constitute an abuse of a dominant market position.
Alongside the proceedings, regulators issued a Preliminary Assessment outlining the facts and competition concerns identified so far. Sanofi now has the opportunity to propose commitments aimed at addressing those concerns.
SNY Stock Price Activity: Sanofi shares were up 1.58% at $42.46 at the time of publication on Friday, according to Benzinga Pro data.