Merck Initiates Phase 3 Study Evaluating Dengue Vaccine Candidate

June 12, 2025 at 06:45 AM EDT

MOBILIZE-1 is the first Phase 3 study being initiated for V181 as part of a planned robust clinical development program

Study will evaluate a single dose of V181 for the prevention of dengue disease caused by any of the four serotypes of the dengue virus regardless of previous exposure

Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced the initiation of the MOBILIZE-1 Phase 3 clinical trial evaluating the safety, immunogenicity and efficacy of a single dose of V181, an investigational quadrivalent vaccine, for the prevention of dengue disease caused by any of the four dengue virus serotypes (DENV-1, DENV-2, DENV-3, and DENV-4), regardless of prior dengue exposure. Recruitment for the trial has begun, and the first participants are now enrolling in Singapore.

“Approximately half of the world’s population live in areas with a risk for dengue, making it a serious public health threat,” said Dr. Paula Annunziato, senior vice president, infectious diseases and vaccines, global clinical development, Merck Research Laboratories. “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.”

Merck is committed to research and innovation that aims to help protect the millions of people at risk for dengue virus infection and is establishing a program of clinical trials for V181, including conducting trials globally, in places where dengue is a significant health threat.

About MOBILIZE-1 (NCT07013487)

MOBILIZE-1, also known as V181-005, is a Phase 3, randomized, double-blind, placebo-controlled study evaluating the safety, immunogenicity and efficacy of V181, an investigational vaccine for the prevention of dengue disease. The study aims to enroll approximately 12,000 healthy individuals 2 to 17 years of age who will be randomized to receive either a single dose of V181 or placebo. The study is planned to include more than 30 trial sites in dengue endemic areas in the Asia-Pacific region, including Indonesia, Malaysia, Philippines, Singapore, Thailand and Vietnam. The primary endpoints of the study are safety and efficacy of a single dose of V181 in preventing symptomatic virologically confirmed dengue (VCD) of any severity, due to any of the four dengue serotypes, regardless of prior dengue exposure. The key secondary efficacy endpoint is evaluating a single dose of V181 in preventing symptomatic VCD of any severity due to each of the four dengue serotypes, regardless of prior dengue exposure. Additional secondary endpoints include evaluating a single dose of V181 in preventing symptomatic VCD with warning signs, severe VCD and hospitalization.

For more information on the trial, visit clinicaltrials.gov.

About V181

V181 is a live attenuated quadrivalent vaccine currently being investigated for the prevention of dengue disease caused by any of the four dengue virus types (DENV-1, DENV-2, DENV-3, and DENV-4). V181 is designed to be a single-dose vaccination and is being studied in individuals to provide protection against dengue, including severe forms, whether the individuals have been previously infected with the dengue virus or had no prior infections.

About Dengue disease

Dengue disease is one of the fastest growing mosquito-borne diseases that affects not just the health but often the economic stability of communities across the globe. It is a rapidly emerging cause of serious and sometimes debilitating illness in tropical and subtropical countries. With approximately half of the world’s population, or four billion people, at risk for dengue disease, it represents a critical public health challenge. Globally, around 105 million dengue viral infections occur annually, with approximately 50-60 million being symptomatic on average per year. While the majority of infections are uncomplicated, serious illness caused by dengue can be severe and lead to death (on average, ~4-11 million cases result in hospitalizations per year and there is an average annual incidence of ~29,000 dengue-related deaths worldwide). Symptoms of mild dengue fever may include a high fever, a rash and muscle and joint pain. Dengue fever might evolve to severe dengue, formerly known as dengue hemorrhagic fever, which can cause severe bleeding, a sudden drop in blood pressure, and in rare cases, death.

About Merck

At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter), Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Rahway, N.J., USA

This news release of Merck & Co., Inc., Rahway, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline candidates that the candidates will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s Annual Report on Form 10-K for the year ended December 31, 2024 and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

View source version on businesswire.com: https://www.businesswire.com/news/home/20250612163655/en/

Contacts

Media Contacts:

Olivia Finucane

0044 7881 262476

olivia.finucane@msd.com

Kimberly Petrillo

(267) 742-2813

kimberly_petrillo@merck.com

Investor Contacts:

Peter Dannenbaum

(732) 594-1579

peter.dannenbaum@merck.com

Damini Chokshi

(732) 594-1577

damini.chokshi@merck.com

About Us

Laser Focus World Membership

Magazine Subscription

Newsletter Subscription

The Daily Beam

Product Watch

Bio & Life Sciences Product Watch

Laser Processing Product Watch

Get Published!

Photonics Hot List

Following the Photons: A Photonics Podcast

Social Media

Meet the Laser Focus World Team

Editorial

Sales

Editorial Advisory Board

Merck Initiates Phase 3 Study Evaluating Dengue Vaccine Candidate

Contacts

More News