
A medicine that people hoped wouldĀ treat chronic fatigue syndromeĀ (CFS) has failed its first large placebo-controlled trial.
The drug, called rituximab, is usedĀ to treat cancer and autoimmune diseases in which the immune system makes antibodies that turn against the body. The medicine works by killing the cells that make antibodies.
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A few people who had cancer and also happened to have CFS saw their symptoms of fatigue resolve after taking rituximab. Ćystein Fluge of Haukeland University Hospital in Norway thought rogue antibodies could be involved in CFS, also known as myalgic encephalomyelitis (ME).
These initial findings were borne out by some small studies. Fluge and his colleaguesā latest trial was larger, involving 151 people. Half had regular infusions of rituximab for a year, whileĀ the rest got placebo infusions. Their symptoms were measured over this time and for a further year, as the drug can take several months to work.
About 25 per cent of people in the treatment group saw their tiredness alleviateĀ ā but so did 35 per cent ofĀ people in the placebo group. Rituximab also caused a higher rate ofĀ side effects that required going toĀ hospital, such as infections.
Fluge says the first people who got better after taking rituximab may have done so because of the placebo effect, or because their condition naturally resolved. Alternatively, theyĀ could have been different in some way from other people with CFS.
The results are a blow to the idea that antibodies cause CFS, says Fluge, ābut it doesnāt exclude that other parts of the immune system are activeĀ in this diseaseā.
Charles Shepherd of the UKās ME Association says some people with the condition have travelled to theĀ USĀ to get rituximab treatment even though it isnāt licensed to be used in this way.
Annals of Internal Medicine