Zika Vaccine Timeline: Will It Be Too Little Too Late?

Following the Zika outbreak in Latin America in late 2015, a number of pharmaceutical companies have stepped up their vaccine research efforts against a virus that has now been scientifically determined as the cause of microcephaly and other severe brain defects in babies. But will a product be able to reach the market soon enough to have an impact on the current outbreak?

Zika virus, which is spread via mosquito bite, was previously considered benign as it caused only flu-like symptoms in some infected people. As such development of new vaccines or treatments is at a very early stage. However, there has been increased government and public concern across various countries after the virus outbreak in Brazil last year was linked to more than 4,000 cases of microcephaly (abnormally small heads) in newborns from October 2015 to January 2016, and a rise in other neurological disorders in adults. (Also see "Zika Virus Vaccine Hunt Begins Following 4,000 Brazilian Birth Defects " - Scrip, 22 Jan, 2016.)

Many countries, including Brazil, the US and European regions, have called for more research into Zika and pharma and biotech firms have been quick to respond – with 16 vaccine products now in preclinical studies for prevention of the virus. (Also see "From One To Seven In 12 Days: ZIKV Vaccine Candidates Speed Into Labs" - Scrip, 3 Feb, 2016.)

In a recent report from Sagient Research's BioMedTracker, Zika Virus At A Glance – Where It Stands Now, analysts have outlined early development timelines for new Zika vaccine products – but the first are not expected to enter human clinical trials until later this year, meaning time to market for a first vaccine could be as long as a decade.

The two most advanced vaccine candidates, Replikins Ltd.'s Zika vaccine and GeneOne Life Science Inc.'s and Inovio Pharmaceuticals Inc.'s GLS-5700, are slated to enter Phase I clinical trials in July 2016 and by the end of 2016, respectively. In addition to the vaccines in development, Ennaid Therapeutics is developing a therapeutic for the Zika virus using peptide fusion inhibitors.

Zika Vaccines In Preclinical Development

Source: Sagient Research's BioMedTracker

Company	Partner	Product	Vaccine Description	Vaccine Classification
GeneOne Life Science, Inc.	Inovio	GLS-5700	undisclosed	DNA-based
Bharat Biotech		ZIKAVAC	undisclosed	inactivated virus
Replikins Ltd.		Trivalent Vaccine	Based on conserved 'Replikin' sequences in the Zika genome	peptide-based
Vaxart Inc.		Zika Vaccine Program	Based on the non-replicating adenovirus type 5 vector (Ad5; oral)	plasmid-based
Bharat Biotech		ZIKAVAC (recombinant)	Based on Zika surface antigens	protein-based
Immunovaccine Inc.	Leidos	DepoVax-Zika	Based on Immunovaccine's DepoVax platform which provides controlled and prolonged exposure of antigens plus adjuvant to the immune system	protein-based
Protein Sciences Corp.	Sinergium Biotech	Zika Vaccine	Based on Zika E protein variants	protein-based
GeoVax Labs, Inc.		GOVX-ZM01	Based on GeoVax's Modified Vaccinia Virus Ankara –Virus-Like Particle (MVA-VLP) vaccine platform	protein-based
VLP Therapeutics LLC		Zika Vaccine	Based on VLP Therapeutics' inserted-alphavirus VLP vaccine technology
Hawaii Biotech Inc.		Zika Vaccine	Undisclosed	Undisclosed
Mymetics Corp.		Zika Vaccine	Undisclosed	Undisclosed
Newlink Genetics Corp.		Zika Vaccine	Undisclosed	Undisclosed
Novavax, Inc.		Zika Vaccine	Undisclosed	Undisclosed
PaxVax Corp.		Zika Vaccine	Undisclosed	Undisclosed
Sanofi		Zika Vaccine	Undisclosed	Undisclosed
Valneva		Zika Vaccine	Undisclosed	Undisclosed

One of the biggest issues causing a delay in vaccine options for tropical diseases like Zika is the industry's reactive method of vaccine development. This model is flawed as waiting until a disease reaches epidemic status, means any potential vaccine or treatment will be available much too late.

The average time to develop a new vaccine product is estimated at 10 years and the cost – from research and discovery to product registration – is estimated to be between $200m and $500m per vaccine. BioMedTracker notes in its report that as with the 2014 Ebola epidemic, "Waiting until the outbreak of a disease to begin development of vaccines or treatments means that by the time one reaches approval, the peak of the outbreak will likely have passed, and the potential of a vaccine or treatment to make an impact is diminished."

Tara Hansen, an analyst at Sagient Research and one of the authors of the BioMedTracker report, told Scrip: "While the neurological or immunological diseases associated with Zika do not occur at very high rates in the population, the disease is spreading fast and wide enough that even a small percentage will be a high number of individuals. The long-term costs of care for raising neonates with microcephaly or caring for adults who develop these complications are also something to consider."

Hansen noted that from her observations, covering the recent Ebola outbreak and now the spread of Zika Virus, "funding and research seem to follow the media attention." She highlighted cases where federal funding for Ebola (which is needed because the risk/reward benefit of developing a vaccine for an infectious disease doesn’t favor development after an epidemic has passed) has been taken from Ebola projects and designated as Zika funding.

Hansen told Scrip that pharma and biotech firms could be better prepared as "most of the diseases emerging now are neglected tropical diseases." However, she highlighted that developing a vaccine is an expensive process with the potential of very little return on the manufacturer's investment. "Without outside sources of funding, most of the vaccines currently in development probably won’t progress past their current stage," she said.

As with other diseases, not a lot of research had been done on Zika virus prior to the current outbreak, which has hindered vaccine development.

In April this year the US Centers for Disease Control and Prevention (CDC) concluded, after a review of existing evidence, that Zika virus was a cause of microcephaly and other severe fetal brain defects. The report, which was published in the New England Journal of Medicine, noted that the finding Zika virus infection can cause microcephaly and other severe fetal brain defects means that a woman who is infected with Zika during pregnancy has an increased risk of having a baby with these health problems. It highlighted though that not all women who have Zika virus infection during pregnancy will have babies with problems.

Furthermore, Zika has been linked to increased rates of Guillain-Barre syndrome (where the body's immune system begins attack nerves, which can lead to paralysis) and acute disseminate encephalomyelitis (ADEM) in areas where the virus is most prevalent.