Sanofi trial failure ends development of breast cancer treatment amcenestrant

[August 17, 2022]  By Ludwig Burger and Tassilo Hummel

(Reuters) -Sanofi stopped further work on amcenestrant, once seen to have large potential against breast cancer, after a second trial failure dealt a major blow to the French healthcare company's development prospects.

The move weighed on shares and put more pressure on Sanofi to bolster its pipeline of drug candidates as it becomes increasingly dependent on its multi-billion best seller, fast-growing exzecma and asthma treatment Dupixent.

Sanofi has also fallen far behind in the race to develop COVID-19 vaccines.

A trial dubbed AMEERA-5, which was testing amcenestrant on women with newly-diagnosed advanced breast cancer, was stopped early because an independent monitoring panel found no signs of it working."All other studies of amcenestrant, including in early-stage breast cancer (AMEERA-6), will be discontinued," Sanofi said.

The shares dropped 4.9% at 0855 GMT, the biggest loss on the French blue chip index CAC40
 

Separately, the plaintiff in the first lawsuit over the heartburn drug Zantac, which has also been weighing on the French company's shares recently, on Tuesday agreed to drop his case.

Sanofi was among a range of companies selling Zantac, which U.S. regulators pulled from the market in 2020.

Since the investor scare over Zantac, which started a week ago, Sanofi shares have dropped more than 13% to a 10-month low, based on closing prices.

In March, Sanofi's shares were hit when the company announced disappointing amcenestrant results of a breast cancer study involving previously treated women.

The company has previously said the drug candidate's biggest commercial opportunity was as a treatment early after diagnosis.

A logo on the Sanofi exhibition space at the Viva Technology conference dedicated to innovation and startups at Porte de Versailles exhibition center in Paris, France June 15, 2022. REUTERS/Benoit Tessier

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

Sanofi said the drug, which was used in combination with Pfizer's established Ibrance in the study, "did not meet the prespecified boundary for continuation," when compared to a group of patients in the trial on standard hormone therapy.

Amcenestrant belongs to a class of pills known as selective oestrogen receptor degraders (SERD) to fight tumours that grow in response to oestrogen, which are estimated to account for up to 80% of all breast cancer cases.

The market opportunity for oral SERDs has attracted a range of drugmakers including Roche and AstraZeneca, who are working on pills known as giredestrant and camizestrant, respectively.

The drugs are designed to work like AstraZeneca's established injectable breast cancer drug Faslodex, while offering a less burdensome route of administration.

Roche and AstraZeneca did not immediately respond to a request for comment.

Another oral SERD, U.S. biotech firm Radius Health Inc’s elacestrant, in which Italy’s unlisted Menarini Group owns rights, has seen better fortunes with a priority review status given by U.S. regulators last week.

Radius Health shares soared in October 2021 on positive elacestrant trial results.

(Editing by Sudip Kar-Gupta, Edmund Blair, Elaine Hardcastle)

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