Combo Drug Therapy May Work Best to Strengthen Bones: Study

But osteoporosis experts say fracture resistance must also be assessed

U.S News & World Report/HealthDay News—May 14, 2013

A new combination drug therapy for osteoporosis appears to increase bone density more effectively than any treatment now on the market, according to the results of a small clinical trial.

Researchers found that postmenopausal women experienced significant amounts of bone growth by taking a bone-building drug called teriparatide with denosumab, a targeted therapy drug used to stop bone loss.

The 12-month study, published online May 15 in The Lancet, was funded in part by the drugs' makers, Eli Lilly and Amgen. It involved 94 postmenopausal women being treated for osteoporosis, a bone-thinning disorder common in old age that makes bones more likely to break.

Researchers divided the group into thirds, with one third receiving a combination therapy of teriparatide (Forteo) and denosumab (Prolia), and the rest taking one medication or the other.

Those treated with both drugs enjoyed significantly better results than those receiving just one.

Bones are in constant flux, with one set of cells forming new bone while other cells break down bone through a process called resorption. After women go through menopause, resorption begins to outpace the formation of new bone, leading to bone thinning and an increased risk of fractures.

Several types of drugs are approved to tackle the problem. Medications such as teriparatide stimulate new bone growth, and drugs such as denosumab reduce bone resorption, but none do both at the same time.

However, it remains to be seen whether the effectiveness of the combination therapy will hold up beyond the first year, a concern shared by Dr. Richard Bockman, chief of endocrinology at Hospital for Special Surgery in New York City.

"This is an interim report, and the data are what they are. I think you have to see the two-year data," Bockman said. "You don't see the full benefit with regards to bone benefit at the hip in the first 12 months. You do see the change at the spine."

And another expert pointed out another possible caveat.

There's some question about whether the new bone grown with this therapy will be better able to resist fractures, said Dr. Joseph Lane, chief of Metabolic Bone Disease Service at Hospital for Special Surgery in New York City.

"It seems to work," Lane said. "This is an important step in the right direction. It proves you can make more bone."

But Lane wonders about the quality of that bone. Only data on fracture healing can address that question, he noted.

The study authors acknowledged that additional research is needed before the combination treatment should be used in clinical practice.

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