MSD aims to plug dengue fever vaccine gap in US
Nearly two years after Takeda pulled its US marketing application for a vaccine against dengue fever, MSD has advanced a rival shot into phase 3.
The international MOBILIZE-1 trial is looking at a single dose of MSD's quadrivalent dengue vaccine V181 – covering all four of the virus' serotypes (DENV-1, DENV-2, DENV-3, and DENV-4), with the first patients now being recruited in Singapore.
While Takeda's Qdenga (TAK-003) shot is approved as a two-dose regimen to protect people from the disease in dozens of countries around the world, the drugmaker withdrew its FDA filing in mid-2023 after a request for additional information from the regulator that the company was unable to provide.
Qdenga was cleared by the World Health Organization (WHO) last year, and sales rocketed to JPY 35.6 billion (around $250 million) in the fiscal year to the end of March 2025, en route to what Takeda has suggested could be a peak of $2 billion or more.
There is one dengue vaccine approved by the FDA – GSK's Dengvaxia – but the jab is restricted to young people aged six to 16 in areas where dengue is endemic and who have previously been infected with the virus, which disqualifies it from being used as a travel vaccine.
MSD is hoping that V181 could offer an option for a much broader population, including those who have not been exposed to dengue before.
"Approximately half of the world's population lives in areas with a risk for dengue, making it a serious public health threat," said Dr Paula Annunziato, head of infectious disease and vaccine clinical development at MSD's Merck Research Laboratories.
If successful, V181 could provide "an important single-dose option for at-risk populations, regardless of previous exposure to dengue, to help reduce the significant burden around the globe," she added.
The WHO has estimated that the mosquito-borne disease infects around 390 million people each year and results in 20,000 deaths. It is endemic in more than 125 countries, including the US territories of Puerto Rico, the US Virgin Islands, and American Samoa, and is a leading cause of fever among travellers to Latin America, the Caribbean, and Southeast Asia.
MOBILIZE-1 has a target enrolment of 12,000 healthy individuals from two to 17 years of age who will be randomised to receive either V181 or placebo at more than 30 trial sites in dengue endemic areas in the Asia-Pacific region, including Indonesia, Malaysia, Philippines, Singapore, Thailand, and Vietnam.
Photo by Towfiqu barbhuiya on Unsplash
