The history of multiple sclerosis is littered with so-called wonder-drugs and miracle cures that raised hopes and then failed to live up to expectations. British doctors are understandably cautious about the prospects for Beta-Interferon but are "encouraged" by preliminary results. The evidence to date from American and Canadian trials suggests that it may be possible to delay (not abolish) the progress of the disease in newly diagnosed, and relapsing/remitting forms of MS. Long-term effects of the drug are unknown. Side-effects include nausea, chills, and a flu-like reaction.

Exactly how it works is not known, although the drug has a role in regulating the immune system, and appears to slow down the excessive activity of immune system cells (T cells and monocytes) implicated in damage to the protective myelin sheath surrounding the nerves.

There are two types of Beta Interferon: Beta-1b or Betaseron, made by Schering, has been available in the US since July 1993. It will be known as Beneseron in Europe. A British licence is expected sometime this year.

Beta-1a, known as Rebif and made by Ares Serono, is undergoing trials in the UK, Europe and Canada. It is expected to be available in the UK in 1996-97. (Another type of Beta-1a made by Biogen is also undergoing trials in the US.)