November 10, 2023: Valneva SE, a French vaccine maker, has got USFDA approval for its chikungunya vaccine, Ixchiq, to treat individuals older than 18 years of age and who are at increased risk of exposure to the disease.
This is the first approved vaccine for chikungunya disease which is spread through the bite of an infected mosquito, according to the US Food and Drug Administration.
The safety of Ixchiq was evaluated in two clinical studies conducted in North America in which about 3,500 participants 18 years of age and older received a dose of the vaccine with one study including about 1,000 participants who received a placebo.
The effectiveness of Ixchiq was based on immune response data from the clinical trials. The immune response of 266 participants who received the vaccine was compared to the immune response of 96 participants who received a placebo.
“The level of antibody evaluated in study participants was based on a level shown to be protective in non-human primates that had received blood from people who had been vaccinated. Almost all vaccine study participants achieved this antibody level,” according to the FDA statement.
Joint pain, fatigue
The most commonly reported side effects by vaccine recipients were headache, fatigue, muscle pain, joint pain, fever, nausea and tenderness at the injection site.
Transmission of chikungunya virus to newborn babies from pregnant individuals with viremia (virus present in the blood) at delivery has been reported and can cause severe, potentially fatal chikungunya virus disease in newborns, according to the FDA.
The drug regulator has told the company to conduct a post-marketing study to assess the serious risk of severe chikungunya-like adverse reactions following the administration of Ixchiq, according to an FDA statement. “As a condition for approval for Ixchiq, the FDA is requiring confirmatory clinical studies to be conducted to verify clinical benefit.”
“The Prescribing Information includes a warning to inform that the vaccine may cause severe or prolonged chikungunya-like adverse reactions” and it includes a warning to inform that it is not known if the vaccine virus can be transmitted from pregnant individuals to newborns, nor is it known if the vaccine virus can cause any adverse effects in the newborn.
Ixchiq is administered as a single dose by injection into the muscle. It contains a live, weakened version of the chikungunya virus and may cause symptoms in the vaccine recipient similar to those experienced by people who have chikungunya disease.
Africa, Southeast Asia
About five million cases of the virus infection have been reported during the past 15 years globally. The highest risk of infection is in tropical and subtropical regions of Africa, Southeast Asia, and parts of the Americas where chikungunya virus-carrying mosquitos are endemic.
The disease has spread to new countries. The most common symptoms of chikungunya include fever and joint pain. Other symptoms may include a rash, headache, and muscle pain. Some individuals may experience debilitating joint pain that persists for months or even years. Treatment includes rest, fluids, and over-the-counter medications for pain and fever.
The “approval addresses an unmet medical need and is an important advancement in the prevention of a potentially debilitating disease with limited treatment options,” said Peter Marks, MD, PhD, director of the FDA’s Center for Biologics Evaluation and Research.
In one study that evaluated whether the vaccine virus was present in the blood after vaccination, most individuals had the vaccine virus detected in the blood within the first week following vaccination; the vaccine virus was not detected 14 days after vaccination.
Ixchiq was approved using the Accelerated Approval pathway. Accelerated approval allows the FDA to approve certain products for serious or life-threatening conditions based on evidence of a product’s effectiveness that is reasonably likely to predict clinical benefit.
According to the FDA’s evaluation of Ixchiq for accelerated approval, “evidence of effectiveness is based on immune response data in clinical trial participants.”
Additionally, the FDA awarded Valneva Austria GmbH a tropical disease priority review voucher, under a provision included in the Food and Drug Administration Amendments Act of 2007.
“This provision aims to encourage the development of new drugs and biological products for the prevention and treatment of certain tropical diseases.”