Takeda's vaccine was 80.2% effective at preventing dengue among
children and teens in the year after they got the shot, according to
results of a Phase III study published in the New England Journal of
Medicine on Wednesday.
Sanofi's Dengvaxia - the world's first dengue vaccine - had
demonstrated 59.2% overall efficacy in the first year of follow-up
based on combined results from two late-stage trials.
There is an urgent need for an effective dengue vaccine. The
tropical disease infects nearly 400 million people a year and kills
up to 25,000 people.
A preliminary analysis of Takeda's vaccine suggests it may offer
unbalanced protection among the four types of dengue. Experts have
long been concerned that a dengue vaccine that is only partially
protective could increase the risk of severe disease after exposure
to a second type of the virus.
The results follow Sanofi's 2017 disclosure that Dengvaxia increased
the risk of severe dengue in children who had no prior dengue
That news triggered an investigation in the Philippines where
800,000 school-age children had already been vaccinated. Fallout
from Sanofi's vaccine has raised the bar for demonstrating the
safety of future dengue vaccines.
Among roughly a quarter of study subjects with no prior dengue
exposure who got Takeda's vaccine, the shot was 75% percent
effective at preventing all four types of dengue.
"This is a fantastic result and we're thrilled," Derek Wallace, who
runs Takeda’s global dengue vaccine program, said in a phone
interview, noting that the results were similar between those who
have and have not had dengue before.
Much of the vaccine's overall benefit, however, appeared in people
infected with dengue 2, the type of dengue that forms the basis of
the vaccine known as TAK-003. It was 97.7% effective at preventing
dengue 2, but lead researchers said the effect was "modest" against
the other three types of the virus.
[to top of second column]
There was no difference in effectiveness against dengue 2 among
those with no prior exposure to dengue and those previously exposed,
and a slightly lower benefit against dengue 1 for those with no
But preliminary evidence suggests the vaccine failed to protect
against dengue 3 in children and teens with no prior dengue
exposure, and there was not enough evidence to make a call about its
effect on dengue 4, researchers said.
The results suggest "there may be an imbalance in the vaccine,
particularly with dengue 3 and maybe dengue 4, but the efficacy was
very good," said Dr. Anna Durbin of the Johns Hopkins Bloomberg
School of Public Health who helped develop a rival dengue vaccine
with the U.S. National Institutes of Health.
Dr Stephen Thomas, a dengue expert at the State University of New
York Upstate Medical University who has been a paid adviser for
Takeda, Sanofi and several other drugmakers, said the results in
dengue 3 "are disappointing from the perspective that the field
desires a vaccine with protective efficacy."
However, Thomas said there is more data coming and more follow-up
underway, and said there is currently "no indication that the
vaccine is doing harm" in people previously exposed to dengue or
Takeda said it plans to file for approval in countries with the
biggest dengue burden, with the first submission expected in the
second half of 2020.
Takeda will release additional data at a medical conference later
(Reporting by Julie Steenhuysen; Editing by Bill Berkrot)
[© 2019 Thomson Reuters. All rights
Copyright 2019 Reuters. All rights reserved. This material may not be published,
broadcast, rewritten or redistributed.
Thompson Reuters is solely responsible for this content.