Hope for steroid-induced osteoporosis?

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Bone Builder: Drug may offer steroid users new protection against fractures

Seppa

In the half-century since their introduction to medicine, glucocorticoid

steroids have been hailed as wonder drugs that have enabled millions of people

to combat rheumatoid arthritis, severe asthma, autoimmune diseases, and

organ-transplant complications. But the drugs have some serious risks, notably

the bone-loss disease osteoporosis. The steroids hamper—and may even

kill—bone-building cells.

To stop bone loss, many people take drugs that preserve existing bone, but a

newer drug, teriparatide (Forteo), activates bone-building cells instead. A new

study finds that boosting bone growth may be the more effective choice for

longtime steroid users who have developed osteoporosis.

Scientists enlisted 428 people who had steroid-induced osteoporosis and randomly

assigned half to receive teriparatide. The others got alendronate (Fosamax), a

drug that preserves bone mass. Average ages in the two groups were 56 and 57,

respectively. The Food and Drug Administration (FDA) has approved both drugs for

osteoporosis but has not cleared teriparatide for steroid-induced bone loss.

After 18 months, 150 patients had maintained their teriparatide treatment and

144 had completed their alendronate treatment. During the study, 1 person on

teriparatide and 10 on alendronate had vertebral fractures. Moreover, patients

getting teriparatide had increases in hip and vertebral bone density that were

significantly greater than such gains in people getting alendronate, the

researchers report in the Nov. 15 New England Journal of Medicine.

" For steroid-induced osteoporosis, teriparatide appears to be a better drug, "

says Adler, an endocrinologist at Virginia Commonwealth University and

the McGuire Veterans Affairs Medical Center in Richmond, who contributed data to

the study.

At the cellular level, the findings suggest that teriparatide is blocking the

biological mechanism by which steroids thwart bone formation and lead to

fractures, says study coauthor G. Saag, a physician and epidemiologist

at the University of Alabama at Birmingham.

In postmenopausal women, osteoporosis develops gradually over several years, but

in people taking steroids, it can appear after as little as 3 months, Adler

says.

" Many of us believed that [teriparatide] would be a better treatment, but we

didn't have the evidence to support that, " says R. McClung, an

endocrinologist at the Oregon Osteoporosis Center in Portland.

Eli Lilly, the company that makes teriparatide, funded the new research. In

2002, the FDA approved the drug for limited use in postmenopausal women at high

risk of fracture. Earlier studies in rats had linked teriparatide with a rare

bone cancer, but no signs of that have shown up in people using it. Even so, the

drug comes with a " black box " warning on its label noting this potential risk.

As part of the regulatory-approval agreement, Lilly agreed to fund a long-term

study monitoring patients for signs of the bone cancer.

On the basis of the new study of steroid users, McClung expects regulatory

approval of teriparatide for patients who use steroids regularly. " This is

exactly the kind of information that the FDA requires " in sanctioning a new use

for a drug, he says.

It would seem tempting to combine the two drugs, so that one could build bone

while the other preserves it. However, earlier tests suggested that bone

preservers blunt the bone-growth effects of teriparatide, McClung says.

References:

Saag, K.G., et al. 2007. Teriparatide or alendronate in glucocorticoid-induced

osteoporosis. New England Journal of Medicine 357(Nov. 15):2028-2039. Abstract

available at http://content.nejm.org/cgi/content/abstract/357/20/2028.