The European Medicines Agency's Committee for Medicinal Products for Human Use (CHMP) has recommended approval of a new vaccine against smallpox, called Imvanex (Bavarian Nordic A/S).

 

The new vaccine is recommended to be used for active immunization against smallpox in adults, the committee said May 30 in a summary opinion.

 

The CHMP recommended that the vaccine be used for primary vaccination (for individuals previously not vaccinated against smallpox) or booster vaccination (for individuals previously vaccinated against smallpox) and can also be used in immunocompromised people.

 

Exceptional Circumstances

 

Unlike traditional smallpox vaccines, Imvanex is nonreplicating, which means it does not proliferate in the body, the committee notes.

 

The active substance of Imvanex is modified vaccinia ankara virus, Bavarian Nordic (MVA-BN). "It is a live attenuated virus which works by inducing the immune system to produce antibodies against the smallpox virus. It will be available as a suspension for subcutaneous injection," the committee said.

 

The committee decided that Imvanex's benefits are greater than its risks after the assessment of 5 main studies involving healthy and immunocompromised people. "The studies showed that Imvanex was effective at stimulating an immune response against MVA-BN when used as primary or as booster vaccination," the committee said.

 

However, because of the rarity of the condition and the fact that clinical trials cannot be carried out, comprehensive efficacy and safety data were not available at the time of the assessment, and the CHMP therefore recommended that Imvanex be approved for use in the European Union under exceptional circumstances.

 

"In exceptional circumstances, an authorization may be granted subject to certain specific obligations, to be reviewed annually," the committee explains. "This happens when the applicant can show that they are unable to provide comprehensive data on the efficacy and safety of the medicinal product, due to the rarity of the condition it is intended for, limited scientific knowledge in the area concerned, or ethical considerations involved in the collection of such data."

 

Studies show Imvanex is generally well-tolerated. The most common adverse effects are headache, myalgia, nausea, fatigue and erythema, induration, pruritus, or swelling at the injection site.

 

The CHMP's positive opinion on Imvanex will now be sent to the European Commission for a final decision.

 

Medscape