1960
1980
2000
2019
SOURCE: TRENDS IN MICROBIOLOGY
NUMBER OF REPORTED DENGUE TYPES 1 2 3 4
A DEBILITATING
DISEASE GOES GLOBAL
THERE ARE FOUR STRAINS OF THE MOSQUITO-
BORNE DENGUE VIRUS. EACH T YPE HAS
SPREAD FROM SOUTHEAST ASIA TO OTHER
PARTS OF THE WORLD IN RECENT DECADES.
one that earned ink in Sanofi’s annual reports
and regular mentions on earnings calls as the
sort of innovative, globally relevant product
that could power the company’s growth.
Sanofi had to move quickly though. A
number of other organizations had their own
dengue vaccines in the works.
Being first and fast to this potentially multi
billion dollar market would be critical, and
Sanofi tried to establish an edge by wringing
excess time from the clinical and commer
cial development processes. Its trials ran on
a compressed schedule, with Dengvaxia’s
expensive Phase III studies beginning before
Phase IIb had ended. The company also
ramped up manufacturing years in advance
so that it would have a ready supply when the
vaccine was eventually approved.
Determined to do everything possible to
ensure the vaccine would become a commercial
success, Sanofi created a new internal struc
ture, the Lyonbased Dengue Company, that
was designed to be an agile and allencompass
ing “team of teams.” Every function—regula
tory, marketing, distribution—was represented
in the unit to more quickly coordinate work.
In May 2013, Viehbacher painted a rosy
picture: “We’ve got ourselves a robust dengue
vaccine,” he told analysts. He predicted the
company would be producing 100 million
doses annually by 2015. “This is a major not
only public health issue but I think a commer
cial opportunity,” he said. “This affects half the
world’s population.”
Sanofi’s optimism, though, wasn’t fully sup
ported by the drug’s test results: The company
had already begun its two Phase III trials
when the results from the Phase IIb trial came
in. They were disappointing: Tested on 4,000
children in Thailand, the vaccine had reduced
dengue infections in kids by just 30% in the
twoyear followup period. In short, the vac
cine had fallen far short of expectations.
But the Phase III results—based on two
studies of 31,000 children in 10 countries—
were more promising. Dengvaxia didn’t work
perfectly. But Sanofi and the scientific com
munity believed they had a vaccine that could
make a difference against dengue.
Tackling a Year-Round Killer
“DENGUE IS REALLY, really difficult,” says Stephen
J. Thomas, a professor at SUNY Upstate
Medical University who started studying the
virus as a doctor with the U.S. Army a couple
of decades ago. Questions that were raised