The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has recommended adjusting the marketing authorisation of Bavarian Nordic’s smallpox and mpox vaccine Imvanex (MVA-BN), based on the inclusion of real-world effectiveness data.
The recommendation is following a type II variation request by the Danish vaccine maker, as per a 26 July press release. A type II variation is when a major change is needed in the marketing authorisation for a medicine approved in Europe.
Bavarian Nordic originally received approval for the vaccine, also known under the brand names Jynneos and Imvamune, in 2013 for smallpox prevention, which was then extended in 2022 to include mpox.
The approval was before the mpox outbreak in 2022 and was therefore based on data in non-human primates and immunogenicity insights from healthy volunteers. The results demonstrated that Imvanex had a good safety profile and induced immune responses that were non-inferior to traditional smallpox vaccines. Smallpox vaccines are known to also protect against mpox, which is in the same viral family.
After real-world observational studies were conducted in eligible individuals after the outbreak, Bavarian Nordic submitted a new application to the EMA for a type 2 variation.
Mpox is an infectious disease caused by the monkeypox virus. It can lead to painful rashes, enlarged lymph nodes, and a fever. Usually those infected make a full recovery, but it can be fatal in certain situations.
Since the outbreak in early 2022, there have been 62,564 cases in the Americas and 27,429 cases in Europe. Africa is experiencing the highest monthly increase in cases, with 281 patients testing positive for mpox in May 2024.
One Imvanex dose conferred an effectiveness of 35% – 89%, whilst two doses bumped up protection to 66% – 90%. Bavarian Nordic also highlighted results from a surveillance study that showed a hospitalisation risk reduction of 73% and 80% for one and two doses, respectively.
The US Centers for Disease Control and Prevention (CDC) currently recommends that those at risk of mpox infection receive a booster dose every two to ten years, since the length of protection from the vaccine is currently unknown.
While the real-world studies will provide further insight, the CDC has stated it is currently analysing data and conducting its own studies to see how long the vaccine effectiveness lasts.
The vaccine was originally developed in collaboration with the US government to ensure supply of a smallpox vaccine for the country.
Imvanex nearly tripled its sales last year from 2022, generating $730m. The revenues came from contracts with various governments, including the US. The vaccine was a main driver of the company’s growth last year.
Bavarian Nordic’s CEO Paul Chaplin said: “The 2022 global mpox outbreak provided an opportunity to assess the effectiveness of our vaccine in at-risk populations across different geographies, both before and after exposure to the mpox virus, and we are pleased to receive the recommendation to include real-life data in our marketing authorisation in Europe.”

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