Chikungunya: vaccine developed in partnership with Butantan induced protective antibody titers in 98.5% of study participants

Valneva will transfer its vaccine technology to Butantan, which will develop, produce and market it in low-income countries

In partnership with the Butantan Institute, French-Austrian pharmaceutical Valneva is developing a vaccine against chikungunya fever that has shown promising results in Phase 3 clinical trials carried out in the United States, raising hopes that a protective vaccine will be available soon. The immunizing agent, internationally called VLA1553, was tested in 4,115 people and generated neutralizing antibodies in 98.5% of volunteers 28 days after the application of the single dose. The percentage is well above the 70% limit agreed with the US regulator, Food and Drug Administration (FDA), to be used in a commercial authorization application. The vaccine candidate was also highly immunogenic, even in older participants, and was generally well tolerated. The immunizing agent had already shown excellent results in previous stages of research: in Phase 1, there was 100% seroconversion in the 120 volunteers, and the antibodies were maintained even after a year. Based on these results, the study progressed directly to Phase 3. The forecast is that the final results of the clinical trials will be released within the next six months.

The vaccine candidate uses a live attenuated version of chikungunya, that is, a weakened version that can still replicate but does not cause the disease. Valnevas medical director, Dr. Juan Carlos Jaramillo, explains that it is based on the Eastern, Southern and Central Africa (ESCA) strain that has spread across the Indian Ocean. According to Dr. Jaramillo, it cross-reacts with other strains, which means that VLA1553 was developed to protect against them as well, including the Asian strain that is rapidly spreading across the Americas, as seen in preclinical studies. “Considering that we designed VLA1553 as a live attenuated vaccine, we believe it can provide lifelong immunity, which will have to be demonstrated through clinical trials”, he adds. Also the product is lyophilized, which provides optimized storage conditions.

To make VLA1553 more accessible to Low and Middle Income Countries (LMICs), Valneva and the Butantan Institute have signed definitive agreements for the development, production and commercialization of the VLA1553 single injection vaccine, in January of this year. Valnevas medical director clarifies that with the collaboration, Valneva will transfer the chikungunya vaccine technology to the Butantan Institute, which will develop, produce and market the vaccine in LMICs. In addition, Butantan will provide some Phase 4 clinical and observational studies that Valneva will use to meet regulatory requirements. The collaboration falls within the framework of the $23.4 million financing agreement that Valneva signed with the Coalition for Epidemic Preparedness Innovations (CEPI) in July 2019, points out.

Chikungunya is a viral disease transmitted by the bite of the Aedes aegypti mosquito, the same vector as dengue, Zika and yellow fever. The circulation of the virus was identified in Brazil for the first time in 2014, and it has already spread to over 100 countries. In addition to posing a major threat to public health, chikungunya causes temporary incapacitation that can leave many professionals unable to work. Yet, these are not all of the complications: about half of the cases progress to the chronic form, in which pain and inflammation last for more than three months. For about half of infected people, the disease causes fever and joint pain that quickly disappears; but for the other half, it can lead to a form of arthritis that can last for months or even years.

The areas of greatest risk of infection are places where chikungunya virus-carrying mosquitoes are endemic. The disease is most prevalent in the Americas, parts of Africa and Southeast Asia. But an increasing number of outbreaks have been reported in Europe in recent years as a result of climate change and mosquitoes spreading further north. As of September 2020, there were more than 3 million cases reported in the Americas and the economic impact is considered significant (e.g., the outbreak in Colombia in 2014: US$73.6 million). The medical and economic burden is expected to grow as the primary vector mosquitoes for CHIKV continue to spread geographically. To check the cases of the disease, click here.

The disease has become an important public health problem in countries where epidemics occur, as half of the cases evolve with chronic, persistent and disabling arthritis. The disease is estimated to affect more than one million people annually. Although millions of people have been affected by chikungunya fever, there are currently no preventive vaccines or effective treatments available against this debilitating disease. To date, VLA1553 is the only one that is in Phase 3 clinical trials. Dr. Jaramillo emphasizes that the partnership with Butantan for the national development, production and marketing of the vaccine will allow the prevention of thousands of cases of chikungunya infections annually, in addition to the complications that can be caused in the long term. “The terrible impact of the COVID-19 pandemic on society has highlighted the importance of vaccines in combating public health crises. Our collaboration with the Butantan Institute can help meet this urgent public health need and accelerate the development of a chikungunya vaccine in low-income countries, which tend to be high-risk areas for an outbreak, concludes Dr. Jaramillo.