Betaferon NAbs not key to poor clinical response

Bayer Schering Pharma AG, a division of Germany's Bayer group, says that the results of a retrospective study demonstrate that the presence of neutralizing antibodies to its multiple sclerosis drug Betaferon (interferon beta-1b, sold as Betaseron outside the USA and Canada), is not predictive of a poor response to treatment.

The firm said that the trial in question, data from which was published in the March issue of the Journal of International Medical Research, suggested that the NAbs that do develop in response to the drug tend to disappear over time and are not related to therapeutic efficacy.

The trial assessed the NAb status of 6,698 Betaferon users at sites in Australia, North America and Europe using the myxovirus protein A assay. In the Australian cohort, the prevalence of high neutralizing antibodies to the drug, regardless of clinical response status, was around 37%, similar to observations made during clinical trials. The prevalence in Europe and North America was 28% and 21%, respectively.