Researchers have claimed that a combination of two FDA-approved osteoporosis drugs having different mechanisms of action increases bone density better than treatment with either drug alone.
The Massachusetts General Hospital (MGH) investigators found that a treatment that combined denosumab (Prolia) and teriparatide (Forteo) was superior to single-agent treatment in a 12-month trial in women with postmenopausal osteoporosis.
For the study, the researchers enrolled 100 postmenopausal women found to be at high fracture risk, based on their bone density and other risk factors, and randomly divided them into three groups.
Over the 12-month study period, one group received a subcutaneous 60 mg dose of denosumab every six months, another group self-administered daily 20-microgram injections of teriparatide, and the third group received both drugs at the same dosage schedules.
Bone density and blood tests were taken at the outset of the study and after 3, 6 and 12 months, and the final analysis included 94 participants who completed at least one follow-up visit.
Participants receiving treatment with both drugs had significantly better results than those receiving just one at several measured sites.
In considering possible reasons for this combination's superiority over combined bisphosphonate and teriparatide, Leder said that teriparatide actually stimulates both bone formation and resorption and that denosumab may more completely block teriparatide-induced resorption while only partially interfering with the drug's stimulation of bone formation.
Benjamin Leder, MD, of the MGH Endocrine Unit, corresponding author of the study, noted that longer studies are required in larger groups of patients to assess the combination's ability to reduce fracture risk and its long-term safety.
The findings of the study have been published in The Lancet.
