Takeda's dengue vaccine efficacy slips between 12- and 18-month analyses

Takeda HQ
Takeda's phase 3 dengue trial will test its vaccine for four-and-a-half years. (Takeda)

Takeda just this month released 12-month efficacy data from a massive dengue vaccine study showing the shot was 80% effective against all dengue strains. But a newer data set shows the efficacy fell slightly in the months that followed. 

In a new 18-month data analysis from the study released over the weekend, Takeda’s TAK-003 was 73.3% effective overall. Within that number, efficacy figures for dengue serotype 3 raised concerns.

The shot was 49% effective at 18 months against that individual serotype, a result Takeda said was "statistically inconclusive but suggests a lack of efficacy." Efficacy figures for serotypes 1 and 2 each came in higher, and for serotype 4, investigators couldn't reach a conclusive finding due to a lack of cases.

RELATED: Takeda's dengue shot 80% effective in massive phase 3 test 

The study, called Tides, is testing TAK-003 against placebo in more than 20,000 participants aged four to 16 in dengue-endemic countries in Latin America and Asia for a total of four-and-a-half years. Takeda plans to file for approval during the second half of next year, Reuters reports. Investigators will continue to monitor participants for another three years, so market watchers will be waiting for future efficacy results to learn more about the vaccine's overall profile.

Takeda's dengue clinical development medical director Shibadas Biswal said in a statement the latest results are “encouraging” but that more data are needed to “fully understand the profile of TAK-003, particularly against serotype 3 in seronegatives.” The company sees the vaccine's "potential to address key priorities for dengue control, including protection of seronegative populations and prevention of hospitalization," Biswal added.

RELATED: Takeda opens €130M plant to produce dengue vaccine it has yet to get approved 

If approved, Takeda’s shot would follow Sanofi’s Dengvaxia onto the market. The French drugmaker launched the product in 2016, but its shot has failed to live up to original expectations thanks to a safety controversy that tripped up the rollout. In 2017, the company said a new analysis found the vaccine could cause more serious disease in those who hadn’t had a prior infection. 

The episode hasn’t scared Takeda away from the field, though. Earlier this month, Takeda opened a €130 million plant in Germany to meet global demand for the shot once it launches.