Sanofi will drop phase 2 dwarfism drug as part of rare disease clear-out

Sanofi has halted work on a phase 2 candidate for a rare growth disorder as part of a pipeline clear-out that saw the French pharma discontinue two other rare disease assets and one of its mRNA flu vaccines.

The most advanced drug to be discontinued (PDF) was an anti-FGFR3 antibody for achondroplasia, the most common type of dwarfism. The asset, called SAR442501, was in a phase 2 trial looking to enroll 36 children aged 12 years or under with hypochondroplasia in Australia, according to Sanofi’s website.

Last month, BridgeBio unveiled the latest phase 2 data for the achondroplasia FGFR3 inhibitor infigratinib, which suggested it may have an edge over BioMarin’s approved dwarfism therapy Voxzogo. BridgeBio has already entered infigratinib into a phase 3 study and it's also being studied in hypochondroplasia.  

The other three candidates Sanofi removed from its pipeline were all in phase 1 development. They included an mRNA quadrivalent flu vaccine called SP0273. The vaccine performed well against influenza strain A last year but struggled against strain B, leading Sanofi executives to claim last summer that the first generation of mRNA flu vaccines “will not win.”

At the time, executives explained that the company was working on a new generation of mRNA flu vaccines, including bringing five different lipids into clinical trials.

On a call with analysts this morning, Sanofi's vaccines chief Thomas Triomphe explained that this is what had happened to SP0273. “We are moving our phase 1 mRNA flu [program] from one product to another, very simply fully in line with what we discussed at the investors event last year,” Triomphe said on the call.

In its place has been slotted in SP0237, another mRNA flu vaccine that entered a phase 1 trial in the second quarter of this year. Triomphe told analysts this morning that SP0237 marks the “next stage” of Sanofi's mRNA flu development.

An mRNA vaccine for acne also entered the clinic over the same period, while Sanofi’s mRNA vaccine for respiratory syncytial virus for older adults is already in phase 2 development.

The other two candidates removed from the phase 1 pipeline were both for rare diseases. One was a TGF beta-1 monoclonal antibody called SAR439459 that was being evaluated in a fragile bone disorder called osteogenesis imperfecta, while the other was an AAV-based gene therapy for SAR444836 being assessed for an inherited disorder called phenylketonuria.

When asked for more context on the decision to deprioritize the three rare disease drugs, a Sanofi spokesperon told Fierce Biotech via email that the company is “continuing the studies until the end.”

“In due time, we will discuss and determine the next course of action to the benefit of patients, potentially with third parties,” the spokesperson added.

The latest pipeline pruning comes against a backdrop of a major restructure at Sanofi. A significant investment shift was first laid out by CEO Paul Hudson in October 2023 when he unveiled the next chapter of his “Play to Win” strategy, which included redirecting resources toward more successful therapeutic areas such as immunology.

In April of this year, Fierce Biotech reported that Sanofi had informed employees of a “full pipeline reprioritization project” that would see fewer research projects in order to fund an increase in the number of phase 3 trials.

Editor's Note: This story was updated at 10:30 a.m. ET on July 26, 2024, to clarify that BridgeBio's recent results were for achondroplasia, not hypochondroplasia.