An FDA advisory committee voted 7-6, with one abstention, that data provided by Sanofi do not support the effectiveness of the drugmaker's dengue vaccine Dengvaxia in patients aged nine to 45 years living in endemic areas who were previously diagnosed with dengue. However, the panel voted 13-1 that Dengvaxia effectively prevents disease caused by serotypes 1-4 in children aged nine to less than 17 years with a prior confirmed diagnosis of dengue and residence in endemic areas.
With regards to safety, the committee was evenly split concerning Dengvaxia's use in patients aged nine to 45, and backed the safety of the vaccine in children aged nine to less than 17 by a 10-4 vote. Sanofi said in a statement to FirstWord that it will continue to work with the FDA, which is evaluating the marketing application for Dengvaxia under a priority review, with a decision expected by May 1.
Sanofi's filing was supported by a clinical trial programme consisting of 16 studies, including two Phase III trials. In the late-stage CYD15 study of children aged nine to 16 years, Dengvaxia met the main goal with an estimated vaccine efficacy rate of 60.8 percent. The primary endpoint of the Phase III CYD14 study in children aged two to 14 years was also met, with an estimated vaccine efficacy rate of 56.5 percent.
The agency noted that Sanofi requested approval of the vaccine for use in children and adults aged nine to 45 years, after analyses of long-term follow-up data uncovered an "increased risk of severe dengue in younger cohorts of Dengvaxia recipients, particularly in subjects two to five years of age."
Earlier this month, authorities in the Philippines said they were going to lay criminal charges against Sanofi executives over the deaths of children who had received Dengvaxia. The country halted its dengue immunisation programme in 2017 after Sanofi announced that Dengvaxia could increase the risk of severe illness in people who had not been previously exposed to the virus.
Dengvaxia gained approval in Mexico in 2015, becoming the first dengue vaccine to reach the market anywhere globally. An advisory group of the World Health Organization later supported use of the vaccine in countries with high dengue transmission. It was cleared in the EU this past December.
Earlier this year, Takeda announced data from the late-stage TIDES trial showing that its live-attenuated tetravalent dengue vaccine candidate TAK-003 was effective at preventing dengue fever caused by any of the four serotypes of the virus.
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