LONDON, Nov 28 (Reuters) - Japan's Takeda Pharmaceutical has moved ahead in the race to develop a vaccine for the mosquito-borne Zika virus, with the start of a clinical trial program backed by the U.S. government.
Its French rival Sanofi had initially been viewed as the large drugmaker best placed to bring the first vaccine to market when Zika erupted as a major public health hazard in Brazil in 2015.
But making such a vaccine proved more difficult than hoped and the U.S. Department of Health and Human Services' development arm BARDA reduced support for Sanofi's project, causing it to end development efforts in September.
Both Takeda and Sanofi have been working on similar vaccines using inactivated or killed whole Zika virus. This type of vaccine has been widely used to protect against a range of diseases and has a good safety record.
Other small biotech companies are working on a more experimental approach focused on DNA-based vaccines, which are made by reproducing sections of the Zika virus genome in a lab.
Takeda said on Tuesday it expected results next year from its 240-patient Phase I Zika vaccine clinical trial, which is taking place in the continental United States and U.S. territories.
The World Health Organization declared the Zika outbreak a public health emergency of international concern in February 2016, although it has since downgraded the threat. However, Zika remains a significant public health risk, especially for pregnant women, and a vaccine is still needed.
Two years ago, when Zika was making headlines after causing thousands of birth defects in Brazil, scientists were predicting a vaccine might be produced in record time, perhaps before the end of the decade.
But current development timelines suggest one won't be ready until the 2020s. Even if Takeda's shot succeeds in Phase I studies, it will still need to progress through two further stages of testing before it is ready for regulatory approval.
For the Japanese company, developing a Zika vaccine is an important milestone in proving its vaccines division can compete with global players.
Takeda also has a vaccine in late-stage development against dengue fever - another mosquito-borne virus with similarities to Zika - that will compete against Sanofi's Dengvaxia, the first dengue vaccine to reach the market. (Reporting by Ben Hirschler. Editing by Jane Merriman)