THE early promise of a genetically engineered antibody designed to combat
the symptoms of rheumatoid arthritis has been borne out by two new studies. In
a small trial last year, the antibody dramatically reduced the pain, swelling
and stiffness caused by the disease. But the authors urged caution until the
drug was tested further.
Now, one of the new studies shows that a single dose of the antibody
alleviates symptoms much more effectively than a placebo injection. The other
confirms the benefit of repeated doses over periods of up to two years. 鈥淚t鈥檚
tremendously good news for people with rheumatoid arthritis,鈥� says Marc
Feldmann of the Kennedy Institute of Rheumatology in London, who led the
research. Both studies were published in last week鈥檚 issue of The Lancet.
The drug inactivates a protein called tumour necrosis factor (TNF), a
chemical messenger which Feldmann鈥檚 team has shown triggers immune responses
(New 杏吧原创, Science, 12 February). In people with rheumatoid arthritis
these immune responses turn against the body, destroying cartilage and bone in
the joints.
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The antibody is produced by Centocor, a biotechnology company based in
Pennsylvania. The part of the antibody molecule that binds to TNF comes from
mice. It would provoke an immune response if the human immune system
recognised it as foreign, so it is disguised by being attached to part of a
human antibody
In the first of the studies, 73 people were assigned at random to receive a
high or low dose of the drug, or a placebo. In the high-dose group, 80 per
cent had greatly reduced symptoms. 鈥淢any could do almost anything they wanted,
and some went back to work for the first time in years,鈥� says Feldmann.
In the second trial, the team gave repeat doses to patients whose symptoms
flared up after the drug鈥檚 benefit had worn off. Patients recovered from four
cycles of relapse, suggesting extra doses could keep the disease at bay over
long periods. 鈥淲e can鈥檛 say whether the existing antibody will be safe and
effective over many years,鈥� warns Feldmann. But if further trials are
successful the drug could be on sale in three years鈥� time.
