The Latest News in Rheumatology
6/28/2002
Overview: How Should Clinicians Manage Osteoporosis in
Ankylosing Spondylitis? Switching
Medications: Etanercept (Enbrel®)
and Infliximab (Remicade®) FDA
Approves Once-Weekly Risedronate for Use in Osteoporosis Treatment and
Prevention
Osteoporosis is a common complication of AS, but current definitions of
osteoporosis were created for postmenopausal women. The definitions may
not be applicable to patients with systematic diseases such as AS. Rupa Bessant
(MSc, MRCP) and Andrew Keat (MD, FRCP) from the Department of Rheumatology in
Northwick Park Hospital, UK, published their findings on osteoporosis' role in
AS a recent article in The Journal of Rheumatology.
AS is usually diagnosed in the third or fourth decades of life. More males
seem to have the disease, and are prone to both more severe AS and a higher
incidence of osteoporosis. Exact numbers are not available. In contrast,
osteoporosis tends to occur from the fifth decade onwards, and is more common in
women than men, yet osteoporotic vertebral factures occur equally in men and
women over the age of 50. Severity and activity of disease, as well as low body
mass index and low fat mass percentage, are high risk associations of
osteoporosis and AS.
The reported prevalence of osteoporosis in people with AS varies from 18.7%
to 62%, depending on differing methods of research. Men with AS lose bone at a
rate of 2.2% annually with a 2.9% annual loss of total body calcium. Men without
AS over the age of 50 lose only 0.7% of total body calcium a year.
Up to 21% of patients with AS experience osteoporotic vertebral compression
fractures, which is 5 times more than non-AS patients. In AS, osteoporosis and
its associated fractures appear to affect the spine exclusively, while
rheumatoid arthritis patients suffer generalized bone loss.
People with AS are at greater risk of developing fractures, especially
of the spine. Indeed, in patients with vertebral osteoporosis, even
relatively minor accidents can lead to spinal fracture and dislocation with
damage to the spinal cord. Patients with AS also have a higher incidence of
spinal cord injury following spinal fracture dislocations, results of which
range from mild sensory loss to total paraplegia.
In the US many rheumatologists recommend osteoporosis screening in their AS
patients s that treatment can begin before irreversible damage can occur.
Current treatment for osteoporosis in AS is similar to that used in primary
osteoporosis. Further studies are recommended to determine appropriate
treatment for osteoporosis in AS.
Stockholm, Sweden--At a recent EULAR meeting, Dr. Ronald F. van
Vollenhoven (Rheumatology, Karolinksa Hospital, Sweden) and his team researched
a hot topic in the medical industry: If a patient failed to respond to or could
not tolerate one of the TNF inhibitors, could the patient respond well to
another TNF inhibitor?
Results: Researchers identified 18 rheumatoid arthritis (RA) patients
treated with etanercept who switched to infliximab, and 13 RA patients who did
the reverse at Karolinska and Huddinge hospitals in Sweden. For those stopping
treatment of etanercept, they cited lack of efficacy and adverse events as
reasons for stopping the medication. Patients who stopped treatment of
infliximab cited problems with infusion reactions, liver toxicity, and lack of
efficacy.
Of the 18 patients who switched to infliximab, 13 patients improved, 2 stayed
the same, and 1 got worse. Van Vollenhoven said, "In patients who fail to
respond to etanercept, better clinical results can be achieved with infliximab."
Of the 13 patients being treated with infliximab (plus methotrexate),
everyone initially did poorly on etanercept but then improved. Overall, 2
patients got better, 8 stayed the same, and 1 got worse. "For patients who
cannot tolerate infliximab, etanercept can give at least similar results, and in
some cases better," stated van Vollenhoven.
From this study, the researchers suggest that a patient with severe RA may
wish to try another anti-TNF alpha drug if they did not respond to the
first drug or if side-effects become intolerable. It is not known whether this
same hypothesis would apply to people with Ankylosing Spondylitis or a Related
Disease.
Strasbourg, France--The FDA has approved a once-weekly form of
risedronate (Actonel®, Aventis) for use in the treatment and prevention of
osteoporosis in postmenopausal women. It is the second product of its kind,
joining the ranks of once-weekly alendronate (Fosamax®, Merck & Co).
One of the known problems in medicine is patient non-compliance. Many people
do not follow their doctors' instructions and only take their medication when
they remember to do so, or if they start feeling symptoms returning. Studies have
shown that by only having to take a medication once a week patient
compliance in this class of drugs may improve. Based on an international
study on 406 postmenopausal women with osteoporosis, 84% preferred the
once-weekly regimen, saying it was more convenient and that they were more
likely to take it long-term. In a US study of 287 women, 90% preferred taking a
pill once a week, 92% said it was more convenient, and 91% said they were more
likely to follow long-term usage.
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