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Merck has initiated MOBILIZE-1, the first phase 3 clinical trial of its investigational dengue vaccine candidate, V181, to evaluate its safety, immunogenicity, and efficacy in preventing dengue caused by all four virus serotypes, regardless of prior exposure.
Enrollment has begun in Singapore, with the study targeting approximately 12,000 participants aged two to 17 years across more than 30 sites in dengue-endemic regions of the Asia-Pacific, including Indonesia, Malaysia, the Philippines, Thailand, and Vietnam. The randomized, double-blind, placebo-controlled trial will assess the vaccine’s ability to prevent symptomatic, virologically confirmed dengue (VCD) of any severity.
V181 is a live attenuated quadrivalent vaccine designed for single-dose administration. While still investigational, it has the potential to provide protection across serotypes DENV-1 through DENV-4, a critical need in global dengue prevention efforts. The primary endpoints include safety and efficacy against symptomatic VCD; secondary endpoints include efficacy against severe VCD and dengue-related hospitalizations.
What You Need To Know
Merck has begun MOBILIZE-1, the first phase 3 trial of its single-dose dengue vaccine candidate V181 to assess safety and efficacy in children aged 2–17 in dengue-endemic Asia-Pacific regions.
The study plans to enroll approximately 12,000 participants and measure the prevention of symptomatic VCD.
Symptomatic dengue presents with clinical signs like high fever and rash, confirmed by laboratory tests.
According to Merck, about half the global population lives in areas at risk for dengue, with up to 105 million infections annually and approximately 29,000 dengue-related deaths. The company continues to expand its dengue research program and is seeking partners to support further development and regulatory engagement.
Paula Annunziato, senior vice president, infectious diseases and vaccines, global clinical development, Merck Research Laboratories, said, “The initiation of the MOBILIZE-1 study, the first phase 3 trial in our clinical development program, marks a key milestone in our work to help address this widespread mosquito-borne disease. 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.”
According to the WHO, symptomatic dengue refers to cases where infected individuals exhibit clinical symptoms such as high fever, headache, muscle and joint pain, rash, and nausea. Virologically confirmed dengue means the infection is verified through laboratory testing that detects the presence of the dengue virus. While many infections are asymptomatic or mild, symptomatic cases can sometimes progress to severe dengue, particularly in individuals experiencing a second infection with a different dengue virus serotype, requiring urgent medical care.
