FDA experts gun down a big part of Sanofi’s pitch for their controversial vaccine

Sanofi has taken its controversial dengue vaccine to the FDA, but a panel of outside experts just handed down a mixed decision that could reduce — or even eliminate — any market potential it may have in the US.

In a series of votes Thursday afternoon, the FDA’s vaccine advisers handed down split votes on safety and effectiveness for the pharma giant’s target population, from 9 to 45. They lost the efficacy vote 6 to 7, with one abstention, with a straight 7-7 split on safety.

That’s not good when you’re looking for a clean bill of health from the authorities.

They did note a more favorable opinion for a smaller group of patients aged 9 to less than 17, voting 13 to 1 on efficacy and 10 to 4 on safety.

None of that will build confidence in the vaccine, once tapped as Sanofi’s next big blockbuster. Those dreams all flatlined after the Philippines used it in a mass vaccination campaign for 800,000 children, just before it was widely linked with hospitalizations and a higher risk of death when the vaccine was a child’s first exposure to the virus, setting up a much more severe reaction to a second exposure of wild type dengue.

Just days ago Philippine officials said they were preparing criminal charges against a slate of Sanofi staffers involved in the vaccination campaign — a development that the Paris home office criticized.

This time around, Sanofi sought an OK for patients who had a proven exposure to the virus ahead of their vaccination. The FDA’s internal review highlighted why:

In the initial analyses of long term follow-up data, i.e., through 60 months post-dose 1, a safety signal became apparent for increased risk of severe dengue in the younger cohorts of Dengvaxia recipients, particularly in subjects 2 to 5 years of age. To investigate this signal, the sponsor performed additional laboratory testing and re-analyzed the long-term follow-up data on severe/hospitalized VCD from the efficacy studies CYD14, CYD15, and CYD23. Although age could not be ruled out as a contributing factor, the primary variable associated with increased relative risk of hospitalized VCD in Dengvaxia recipients was dengue non-immune status at baseline. Based on these analyses, the sponsor is requesting approval for use only for individuals 9 through 45 years of age with laboratory-confirmed previous dengue infection and living in endemic areas.

But the restrictions still weren’t good enough for the panel for the broad age group they sought to cater to. The final decision rests with the FDA. Sanofi, meanwhile, continues to insist that it did nothing wrong with their vaccine, which it continues to push in the wake of the global controversy. Takeda, meanwhile, has a rival vaccine in late-stage development.

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VP Oncology Biology
Skyhawk Therapeutics Waltham, MA
Associate Director CMC
Elektroki Boston, MA
Director Process Development
Elektroki Boston, MA
Research Scientist - Immunology
Recursion Pharmaceuticals Salt Lake City, UT

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