Bavarian Nordic gains CHMP approval to amend Imvanex

The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has proposed modifying the marketing authorisation for Bavarian Nordic’s smallpox and mpox vaccine, Imvanex (MVA-BN). This recommendation stems from the inclusion of real-world effectiveness data. The Danish vaccine manufacturer had requested a type II variation, which involves significant changes to the marketing authorisation of a medicine already approved in Europe.

Initially approved in 2013 for smallpox prevention, the vaccine—also known by the names Jynneos and Imvamune—received an extension in 2022 to include mpox. However, the approval was granted before the mpox outbreak of 2022 and was based on data from non-human primates and immunogenicity studies in healthy volunteers. These studies indicated that Imvanex had a good safety profile and induced immune responses comparable to traditional smallpox vaccines. Notably, smallpox vaccines are known to offer protection against mpox, as both viruses belong to the same family.

Following the 2022 mpox outbreak, real-world observational studies were conducted among eligible individuals. Based on these studies, Bavarian Nordic submitted a new application for a type 2 variation to the EMA.

Mpox, caused by the monkeypox virus, results in symptoms such as painful rashes, enlarged lymph nodes, and fever. While most patients recover fully, the disease can be fatal in some cases. Since the outbreak began in early 2022, there have been 62,564 cases in the Americas and 27,429 in Europe. Africa experienced the highest monthly increase in cases, with 281 positive tests for mpox in May 2024.

The effectiveness of the Imvanex vaccine was observed to be between 35% and 89% for one dose, while two doses improved the effectiveness to between 66% and 90%. Furthermore, results from a surveillance study showed a reduction in hospitalisation risk by 73% for one dose and 80% for two doses. The US Centers for Disease Control and Prevention (CDC) currently advises that individuals at risk of mpox infection receive a booster dose every two to ten years, as the duration of vaccine protection is still uncertain. While real-world studies are expected to provide additional insights, the CDC is also conducting its own analyses to ascertain the longevity of the vaccine's effectiveness.

The vaccine was initially developed in partnership with the US government to ensure a reliable supply of smallpox vaccines. Imvanex saw its sales nearly triple in the previous year, generating $730 million. This revenue was derived from contracts with various governments, including the US, and the vaccine significantly contributed to Bavarian Nordic's growth.

Paul Chaplin, CEO of Bavarian Nordic, stated: “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.”