Osteoporosis drugs no better in combination-study
Saturday September 20, 12:27 pm ET
By Deena Beasley
[This looks good.]
LOS ANGELES, Sept 20 (Reuters) - Combining an experimental calcium-controlling hormone that builds bone with a popular osteoporosis drug does not increase bone density any more than the hormone alone, researchers said on Saturday.
"It looks like you don't see the synergism or additive effect that we had hoped to see," said Dennis Black, professor of epidemiology and biostatistics at the University of California, San Francisco and the study's lead investigator.
The interim results come from a one-year study, sponsored by the National Institutes of Health, in 238 post-menopausal women. Some received only Preos, a bioengineered full-length version of human parathyroid hormone, some only Fosamax, an osteoporosis drug sold by Merck & Co. (NYSE:MRK - News), while others were treated with both drugs.
Bone mineral density at the spine increased in all the treatment groups, but was highest, at a rate of 6.3 percent, in the parathyroid hormone group. The volume of spongy bone at the center of the spine also increased, but the 24 percent increase in the parathyroid hormone group was about twice that found in either of the other groups.
Increased bone density at the hip was highest with Fosamax, but the volume of bone was actually higher with Preos. "The inference is that you're building new bone on the outside," Black said, noting that other studies suggest that it takes more than a year of hormone therapy for bones to mineralize.
Results were presented at a meeting of the American Society of Bone and Mineral Research in Minneapolis and published in the latest edition of The New England Journal of Medicine.
"For previously untreated patients, the data now suggest that if therapy with parathyroid hormone is contemplated, it should be used alone ...," Dr. Sundeep Khosia of the Mayo Clinic in Rochester, Minnesota, said in an NEJM editorial.
AGING POPULATION
An aging U.S. population is becoming more susceptible to bone-thinning osteoporosis, which affects 8 million women and 2 million men and causes more than 1.5 million fractures a year.
Preos, under development by NPS Pharmaceuticals Inc. (NasdaqNM:NPSP - News), is part of a new class of injected osteoporosis drugs that build bone rather than simply prevent bone loss as patients age.
The first drug in the class is Eli Lilly & Co.'s (NYSE:LLY - News) Forteo, a fragment of the parathyroid hormone, which was approved in the United States last year for treating severe osteoporosis.
Older drugs like Fosamax are part of a class called biphosphonates that work by stopping or slowing bone loss.
Earlier research had suggested that dual use of the drugs might improve outcomes since they have different mechanisms of action, Black said.
Sundeep theorized that parathyroid hormone-induced increases in bone size are perhaps more important in terms of mechanical strength, and the addition of Fosamax to the regimen impairs the ability of the hormone to induce these changes.
In the study's second year, patients on Preos will discontinue injections, and will be given either Fosamax or a placebo to see if bone gains are maintained. If the bone-building effects of Preos are shown to continue even after a patient stops the therapy, it would make sense to treat more moderately affected osteoporosis patients, Jackson said.
NPS, based in Salt Lake City, expects to unveil top-line results from its own pivotal-stage trial of Preos next March and to file for U.S. Food and Drug Administration (News - Websites) approval of the drug next year.
The company expects in November to have results from a study in rats of whether Preos raises the risk of bone cancer. Forteo carries a warning that rats developed bone cancer after taking high doses of the drug for most of their lives. Neither drug has been linked to tumors in humans. |
