Bavarian Nordic has announced that its Phase III trial of MVA-BN RSV has accrued the number of required cases to complete primary efficacy analysis. The Copenhagen, Denmark-based company said data has confirmed enough cases with more than two and three symptoms as required in the trial.

MVA-BN RSV is being investigated for the prevention of respiratory syncytial virus (RSV) adults over 60 years of age. RSV cases are rising and is estimated to cause approximately 14,000 annual deaths in older US adults.

The trial has enrolled more than 20,000 participants across more than 100 centers in US and Germany. The primary objective is to assess the efficacy of the drug against lower-respiratory tract disease which is caused by RSV.

The pharmaceutical industry has been racing to develop drugs to combat the unprecedented number of RSV cases. A major barrier to treating RSV is the lack of understanding around the virus. Breakthroughs in protein mapping have helped turn the tide in favour of drug development but currently there is no approved vaccine against RSV.

There is growing sentiment, however, that as RSV is an RNA virus, mutations may make the landscape even more difficult. Cases of RSV mutation have already been documented, so pharmaceutical companies have had to develop novel approaches. Bavarian Nordic’s compound incorporates five distinct RSV antigens to stimulate a broad immune response against both RSV subtypes.

“Our candidate has a clearly differentiated approach, as it employs five RSV-specific antigens with an aim to stimulate a broad antibody and cellular immune response against RSV, and we are committed to bringing this vaccine to the market to help minimise the burden from RSV-related disease in the older population,” said Paul Chaplin, president, and chief executive officer of Bavarian Nordic.