Sanofi suffers major blow as its cutting-edge cancer drug disappoints in Phase III trials

By Louis Goss

French pharmaceuticals giant Sanofi (FR:SAN) on Thursday said it would be halting development of a promising cancer treatment after the cutting-edge candidate failed to show better outcomes than a widely-used chemotherapy drug in final stage trials.

In a statement, Sanofi said it would be ending its research into experimental cancer treatment Tusamitamab Ravtansine due to its failure to achieve better outcomes than chemotherapy drug Docetaxel in Phase III trials of patients with lung cancer.

The failed trial comes as a major blow to Sanofi in scuppering hopes for its only antibody-drug conjugate (ADC) candidate, amid widespread excitement around the potential ADCs have to treat cancer with fewer side-effects than chemotherapies.

Shares in Sanofi stayed flat on Thursday having lost 2% of their value over the previous 12 months.

ADCs see human antibodies combined with anti-cancer drugs into complex molecules that are then used to target cancerous tumors. In contrast to chemotherapy drugs, ADCs are engineered to ensure they exclusively kill cancer cells, while keeping healthy cells alive.

Excitement around ADCs has seen the world's top pharmaceutical companies plow billions into researching the drugs with a view to capitalizing on the fast-paced growth in the more than $200 billion a year market for oncology treatments.

Sanofi had previously pinned its hopes on Tusamitamab Ravtansin as a major component of its comparatively sparse ADC pipeline after gaining a license to develop the molecule in 2017 via a $30 million deal with Massachusetts-based ADC specialist ImmunoGen (IMGN).

The Phase III trial of Tusamitamab Ravtansine, however, showed that although the drug was successful in improving "overall survival" it failed to halt progression of patient's cancers compared to Docetaxel.

The trial saw Tusamitamab Ravtansine tested on patients with metastatic non-squamous (NSq) non-small cell lung cancer (NSCLC) whose tumors express high levels of carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5).

The Paris headquartered drugmaker said it would continue carrying out research into cancer and into tusamitamab-based ADCs.

"Although the results are not what we hoped for, our research and work to advance potentially transformative therapies in areas of high unmet need for people living with cancer will not stop," Sanofi's chief medical officer Dietmar Berger said.

-Louis Goss

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12-21-23 0659ET

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