|
Benefits found for Rebif over Avonex in MS, but study
design questioned
A head-to-head study comparing two brands of interferon
beta-1a in multiple sclerosis, conducted by Serono one of the manufacturers,
has shown that patients treated with Rebif are more likely to remain relapse-free
than those treated with Avonex. In response to the study, Biogen, the
manufacturer of Avonex, has issued a statement saying that the data “are
based on a study that lacks scientific rigour” and that the study presents
an incomplete measure of a disease that must be treated over the long-term.
The EVIDENCE (evidence for interferon dose-effect:
European-North American comparative efficacy) study was designed to demonstrate
the clinical benefit of Rebif, which is manufactured by Serono, over Biogen’s
Avonex. In the study, 677 patients with relapsing-remitting MS underwent
repeated clinical and magnetic resonance imaging assessment while taking
either Rebif 44µg three times weekly or Avonex 30µg once weekly in an
open-label fashion.
The results of the study, which were presented last
week at the 17th World Congress of Neurology in London, showed that after
24 weeks 74.9 per cent of patients treated with Rebif were relapse-free
compared with 63.3 per cent of those receiving Avonex (P=0.0005).
Serono presented these data as an adjusted odds ratio of 1.9, which translates
to patients having a 90 per cent greater chance of remaining relapse-free
while on Refib. This presentation of the data, says Biogen, is misleading.
Dr Patricia Coyle of the Stony Brook multiple sclerosis
comprehensive care centre, New York, United States, who presented the
results said: “Clinicians treating multiple sclerosis have been crying
out for a study to test whether the dose of interferon-beta influences
the outcome of the disease. This study shows that all outcome measures
are better for Rebif over Avonex.”
The main secondary endpoint of the trial was the
reduction in combined brain lesion activity as measured by MRI over 24
weeks. Dr Coyle reported that patients treated with Avonex had 50 per
cent more new lesions in the brain than those treated with Rebif (P<0.0001).
She added that both drugs were safe and well tolerated.
Responding to remarks about the brevity of the study,
and the bias caused by the open-label approach, Dr Coyle said that such
remarks were ridiculous. “During the study, all assessing neurologists
and radiologists were blinded to the treatments. A patient knowing which
product they are receiving will not produce lesions in the brain,” she
said.
Biogen has criticised the design of the study and
says in its statement: “There is a wealth of data from well-designed clinical
trials that define the risks and benefits of MS products. Slowing the
progression of disability is the more meaningful measurement of this long-term
chronic disease.”
A spokesman for the Multiple Sclerosis Society told
The Journal on June 27: “Trial evidence has shown beta-interferons
to be of significant benefit to many people with MS. The fact that there
is more than one drug is helpful, and, as time goes on, there will be
an increasing body of evidence that will influence prescribing practice.”
He added that the society’s main concern was that “whichever drug we are
talking about, many people are not getting access to them”.
As part of its appraisal of MS treatments, the National
Institute for Clinical Excellence is to look at interferon-beta. A spokeswoman
for the institute told The Journal on June 27 that NICE considers
classes of drugs, and specific products where the evidence of benefit
exists.
Dr Peter Brambleby, consultant in public health
at Norfolk health authority, spoke to The Journal recently about
cost-effectiveness issues surrounding MS disease modifying drugs and the
role of the NICE in reviewing treatments.
He said that the consequences of the NICE delaying
their appraisal of MS drugs was a problem. “No one at health authority
level will bring in their own policy if they know that the NICE is going
to review a treatment. Some patients could progress beyond eligibility
by the time the NICE says yes or no.”
Dr Brambleby added that if recommendations were
not funded in full then health authorities would manage their budgets
by removing resources from another area.
|
