The original investigators of the Interferon B Study Group, who conducted the pivotal study on interferon B-1b that really started the modern use of interferons in people with MS, have reported the 16 year follow up of a good proportion of the 372 patients originally randomised to receive placebo or low or high dose IFNB-1b.
Nearly 90% of these people were contacted and around 70% had clinical records. The really interesting finding was that 16 years on, using standard disability and MRI measures, the investigators could find no difference in outcome between the three groups.
There was a difference in mortality rates though, with more placebo patients having died since the study than in the treatment groups. Clinical trials by their nature are relatively short term.
These long term data help us determine how effective these drugs really are. The investigators noted that there were a lot of problems with the study that meant that the blinding and randomisation were not rigorous, and perhaps that was why there was no apparent difference at 16 years.
This is an unusual admission. It raises questions about the sort of evidence we use in medicine to license expensive drugs; given that the same sorts of problems were apparent with other interferon studies (lack of blinding due to people knowing they were on the drug because of side effects), it raises serious questions about the evidence base behind the licensing and use of the interferons in Multiple Sclerosis.