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 Although Zika infections are mild or asymptomatic in most people,
demand for a vaccine is expected to be strong because it can cause
devastating birth defects, pharmaceutical executives and disease
experts said.
The most lucrative market is seen in travelers seeking inoculation
against the virus that has moved rapidly across the Americas and is
the only mosquito-borne disease also spread through sex.
"It scares people," said Scott Weaver, a virologist with the
University of Texas and chairman of the Zika task force for the
Global Virus Network. "Europeans and Americans can pay a pretty high
price for these kinds of vaccines."
A vaccine could come to market in as little as two years. Even if
the current outbreaks in Latin America and the Caribbean burn out by
that time, people living in those regions are expected to want
protection against a return of Zika.
Tens of millions of travelers from United States and other wealthy
nations, including people on business trips with corporate-sponsored
health coverage, are expected to get vaccines before visiting areas
where Zika is circulating. "If you consider just a portion of the
U.S. traveler population, we can conservatively envision a Zika
market opportunity exceeding $1 billion" a year, said Joseph Kim,
chief executive of Inovio Pharmaceuticals <INO.O>, a Pennsylvania
company that is farthest along in the development path with human
testing of a vaccine candidate underway in hard hit Puerto Rico.
Drugmakers and disease experts also envision the vaccine becoming
standard care for girls before puberty to guard against birth
defects in future pregnancies. Boys also could be candidates to
protect eventual sexual partners.
"Hopefully a vaccine can be developed that's sold for a low cost in
endemic areas," Weaver said.
ZIKA'S DIFFERENCE
Blockbuster sales for vaccines against mosquito-borne viruses are
unheard of. Sanofi's dengue vaccine, approved in nine countries, is
generating near-blockbuster expectations, the biggest in the market
by far. Analysts forecast annual sales for Dengvaxia reaching about
$900 million by 2020, according to Thomson Reuters data.
Efforts to find a malaria vaccine are purely philanthropic. The Bill
and Melinda Gates Foundation has contributed significantly to GSK's
decades-long effort to produce a vaccine for children in Africa.
Development is ongoing, and GSK expects no profit.
The U.S. National Institutes of Health (NIH) developed a potential
vaccine for West Nile virus, but it failed to find a commercial
partner because the virus did not inspire enough public alarm to
generate big sales. West Nile leads to serious complications in less
than 1 percent of people infected.
In February, the World Health Organization declared a global public
health emergency because of Zika's apparent link to microcephaly, a
birth defect marked by small heads and serious developmental
problems. That, and evidence of other severe fetal brain
abnormalities linked to Zika, have galvanized efforts to speed
vaccine development.
The NIH is negotiating with companies to produce Zika vaccines but
has its own pilot plant that can make enough for early clinical
testing, which began with its first candidate in August.
"We're not dependent on a company until you prove it works and then
you need somebody to manufacture millions of doses," said Dr.
Anthony Fauci, director of the NIH's National Institute of Allergy
and Infectious Diseases (NIAID).
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The first NIH candidate is a DNA vaccine containing no actual virus,
in which genetically engineered cells produce an antigen that
triggers an immune response, similar to the West Nile vaccine. By
early 2017, the agency expects to be able to decide whether to begin
enrolling thousands of patients in an efficacy study, or move on to
the next candidate.
The size of the Zika outbreak may help development efforts. If it
remains widespread, it will be easier to tell if a vaccine is
effective.
"If the infections die down, then it's going to take much longer to
find out if it works," Fauci said.
A second NIH candidate contains inactivated viral material, while a
third utilizes attenuated, or weakened, live virus.
DNA-based candidates are most likely to prove safe, but they
typically require multiple doses to work. Vaccines that contain live
virus are considered most effective with one dose, but have a far
higher safety hurdle, particularly if they are intended for pregnant
women, and so they take longer to get to market.
INDUSTRY PILES IN
Inovio's DNA vaccine is injected along with a brief low voltage
electronic pulse that induces cell membranes to open, making them
more receptive, in theory, to accepting the vaccine's genetic
material.
Privately-held Protein Sciences Corp built its Zika vaccine using
technology similar to its already approved Flublok flu vaccine. The
drugmaker has partnerships with companies in Argentina, Brazil,
Japan and Mexico and plans to seek funding from Brazil and the NIH.
It expects to start human trials by January.
Chief Executive Manon Cox estimated the cost of developing and
securing approval for a vaccine could be as high as $1 billion.
Without government funding, "that product has got to have a market
of a few billion dollars," she said.
With the help of $43 million in initial funding from the U.S.
government, France's Sanofi is developing a candidate using live
attenuated virus. The company is not as far along as some other
efforts, but it aims to start human trials next year and is
confident it can catch up.
"We've got technologies, infrastructure, experience dealing with
regulators in this field. All of that gives us a jumpstart," said
Nick Jackson, head of research for Sanofi's vaccine unit.
Another French vaccine maker, Valneva SE <VLS.PA>, generated an
inactivated Zika vaccine candidate using the same process as its
already approved Japanese encephalitis vaccine.
GSK is working with NIAID on a new type of vaccine technology.
Japan's Takeda also secured U.S. government funding to help develop
a vaccine using killed Zika virus and plans to begin human testing
in the second half of 2017.
"If there is a huge need," said Dr. Rajeev Venkayya, president of
Takeda's global vaccine unit, "there will be a business model that
works."
(Reporting by Bill Berkrot; Editing by Michele Gershberg and Lisa
Girion)
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