April 19, 2026
2 min read
Key takeaways:
- Chikungunya, a neglected tropical disease, is spreading beyond its historical tropical and subtropical boundaries.
- There are no available treatments for the disease, and two licensed vaccines are scarcely used.
MUNICH — A monoclonal antibody being studied as a potential therapy for chikungunya virus infection showed potential as both a treatment for the mosquito-borne disease and as pre-exposure prophylaxis to prevent infection, researchers said.
Hugh Watson, PhD, president of Quayside Research in Lyon, France, and colleagues studied the mAb, called EVT894, in a first-in-human randomized, double-blind, placebo-controlled study at three research sites in the United States. Watson presented findings from the study here at ESCMID Global.
There are no specific treatments for chikungunya, which is rarely fatal but can cause debilitating pain for months or even years. There are two licensed vaccines, but they are scarcely used in the places where they are needed the most, Watson noted. One of the vaccines, Valneva’s Ixchiq, is no longer available in the United States after the FDA suspended its license last year.
Historically, cases of chikungunya occurred only in tropical and subtropical regions, but Aedes mosquitoes carrying the virus are increasingly found outside those ranges, threatening a larger swath of the globe, Watson said.
Countries and territories reporting local cases of the disease numbered 119 as of December 2024, according to WHO, which classifies chikungunya as a neglected tropical disease. That total includes the continental U.S., which mainly experiences travel-related cases of chikungunya but has also seen local transmission in Florida, Texas and most recently New York, which recorded a case last year — the first in any state in a decade. (In the U.S., chikungunya has mainly been associated with the tropical territories of Puerto Rico and the U.S. Virgin Islands since the virus first appeared in the Caribbean in 2014.)
In lieu of a vaccine, EVT894 could provide rapid protection during outbreaks, Watson and colleagues suggested. In preclinical testing, EVT894 “achieved potent neutralizing activity in vitro and in vivo in therapy and prophylaxis models and demonstrated efficacy against all circulating chikungunya genotypes,” according to the French company Evotec, which is developing the drug.
The study presented at ESCMID Global was funded by the NIH’s National Institute of Allergy and Infectious Diseases. It included 40 healthy adults aged 19 to 45 years who were split into five groups that received one of five different doses of the mAb, ranging from 0.3 mg per kg to 20 mg per kg. Six people in each group were vaccinated, and two received a placebo.
None of the participants experienced a severe adverse event in the 150 days of follow-up, although a few had mild treatment-related reactions, Watson and colleagues reported.
The mAb, which was derived from a survivor of chikungunya, remained active for months even at the lower doses, with a half-life ranging from 56 to 99 days, the researchers found. They did not see any evidence that participants developed antibodies against the therapy.
The results indicate that EVT894 could protect someone against chikungunya infection for 4 to 8 months, making it potentially useful to contain epidemics of the disease and as a vaccine alternative for travelers, Watson said. But he said its usefulness as a treatment may depend on rapid diagnosis and early treatment.
Perspective
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Chikungunya epidemics continue to occur around the globe, with a widespread outbreak in the Indian Ocean region in 2024, a large outbreak in Cuba in late 2024 and early 2025, and currently active foci of disease transmission in Brazil and several Caribbean islands.
Chikungunya can cause a severe acute infection characterized by polyarthritis and, in certain high-risk populations such as older patients, women and people with multiple medical co-morbidities or immunocompromise, there is a risk for long term inflammatory arthritis.
Although there are two commercially available vaccines (only one is currently licensed in the United States), there are no treatments for acute chikungunya and only disease moderating agents for the chronic arthritis that develops in a subset of patients. There is thus an urgent need for treatment of acute infections to prevent complications and potential progression to severe disease.
The monoclonal antibody EVT894 is an intriguing future treatment option for acute chikungunya infection given pre-clinical evidence of potential antiviral efficacy and now evidence of the safety and pharmacokinetics of this agent in a placebo-controlled, dose escalation trial. It will be exciting to see this progress to phase 3 clinical trials given the urgent need for therapeutic options for chikungunya.
David H. Hamer, MD
Disclosures: Hamer reports serving on advisory boards for Takeda and Valneva and doing presentations for Bavarian Nordic and Valneva.
Sources/Disclosures
Source:
Watson H, et al. Abstract L0008. Presented at: ESCMID Global; April 17-21, 2026; Munich.
References:
Disclosures:
Watson reports being a paid consultant for Evotec.
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