Study shows effectiveness of abatacept in juvenile idiopathic arthritis
Abatacept may be effective in the treatment of juvenile idiopathic arthritis, a study published online in The Lancet suggests. However, the study has come in for some criticism.
In the double-blind, randomised controlled withdrawal trial, the incidence of arthritis flare was 20 per cent in subjects receiving abatacept, compared with 53 per cent in patients who were given placebo (P=0.0003). No difference was recorded in the frequency of adverse events between the two treatment groups.
Patients participating in the trial were aged 6–17 years, had a history of active juvenile idiopathic arthritis and were refractory or intolerant to at least one disease-modifying antirheumatic drug. A total of 122 subjects were randomly assigned to receive either placebo or 10mg/kg abatacept, administered at 28-day intervals for six months or until a flare of arthritis.
The author of a comment piece, however, criticises the study design and questions the reliability of the results obtained.
Thomas Lehman, of the division of paediatric rheumatology, Hospital for Special Surgery, New York, points out that the trial began with a four-month open-label phase during which all subjects received 10mg/kg of abatacept intravenously. Of the patients who completed this initial phase, only those who responded to abatacept entered the trial.
Mr Lehman suggests that this approach preselects for those subjects who are susceptible to the placebo effect, and so “the possibility that . . . the active treatment group responded to a placebo effect cannot be dismissed easily”. He also points out that the study design does not account for the carry-over effects of abatacept treatment in the open-label phase.
The study was designed, implemented and funded by Bristol-Myers Squibb, who launched abatacept last year under the trade name Orencia. The drug is currently indicated for the treatment of rheumatoid arthritis in refractory adults. However, in April the National Institute for Health and Clinical Excellence rejected the use of abatacept for this indication on cost-effectiveness grounds, despite an appeal by the product’s manufacturer.
Citation: The Pharmaceutical Journal URI: 10024311
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