Sanofi drops experimental breast cancer drug after second trial fails

Sanofi has abandoned development of a once-promising breast cancer drug called amcenestrant after a second failed clinical trial, dealing a blow to its pipeline of new treatments.

The French pharmaceutical group said on Wednesday that it had stopped all studies of the experimental drug following an analysis of late-stage trial data that showed it did not meet the efficacy threshold.

Shares in Sanofi closed down almost 6 per cent on Wednesday, making it the seventh-worst performer on the French blue-chip CAC 40 index.

“This was a flagship drug in pipeline and important oncology asset,” wrote Credit Suisse analyst Jo Walton.

Analysts said the setback raised questions about the strength of Sanofi’s pipeline of drugs and risked leaving it dependent on blockbuster eczema and asthma drug Dupixent. Strong sales of Dupixent prompted the group to raise its annual profit target in late July when it reported second-quarter results.

The failure of amcenestrant came after a setback to an experimental multiple sclerosis treatment called tolebrutinib. In July, the US Food and Drug Administration asked the company to pause recruitment of patients for studies on the drug after reports of side effects to the liver.

Sanofi had previously listed amcenestrant and tolebrutinib as priorities for development, citing them as among six “potentially transformative” treatments in its pipeline.

David Risinger, analyst from SVB Securities, lowered his price target for Sanofi from €121 to €102 as a result of the development of amcenestrant trials ending. “We previously expected a 2025 launch for amcenestrant and estimated €1.6bn in annual sales by 2030,” he wrote in a note, adding that earnings per share would be as much as 7 per cent lower.

John Reed, Sanofi’s head of research and development, said in a statement that cancer treatments remain “a priority area for Sanofi”.

“While we are disappointed by this outcome, our research will further the scientific understanding of endocrine therapies in people with breast cancer,” he added.

Chief executive Paul Hudson has made oncology a focus of the group’s research efforts as part of his five-year turnround plan for the business that began in 2019.

While there have been some successes during Hudson’s tenure, including acquisitions in vaccines and immunology, Sanofi’s shares have lagged behind its peers since he joined the company. They are up about 8 per cent since September 2019, compared with a 35 per cent rise for the MSCI World Pharmaceuticals, Biotechnology and Life Sciences index.

The company’s shares were also hit last week by investor concerns about US lawsuits relating to heartburn drug Zantac, which was withdrawn from the market in 2019. Sanofi was one of several companies that sold the over-the-counter treatment.