Two drugs currently used to treat osteoporosis could produce better results if used in tandem, researchers say.
Using a combination of the drugs, already available on the NHS, resulted in an increase in bone density of up to 5 per cent in just a year, they found.
The US researchers said the improvement achieved from giving patients the drugs teriparatide and denosumab at the same time exceeded any available treatment for women with osteoporosis.
The condition, also known as brittle bone disease, causes damaging loss of bone tissue.
It often has no symptoms until a simple fall results in a broken wrist, shoulder, spine or hip.
Osteoporosis affects an estimated three million people in the UK, and every year there are 300,000 fractures due to fragile bones, many of which could be prevented.
Every month, 1,150 die prematurely as a result of a hip fractures and half of patients do not regain their independence. At least 120,000 people a year suffer spinal fractures.
Most currently available osteoporosis drugs, including denosumab, stop the action of cells that break down bone during the normal process of bone formation.
In contrast, teriparatide – also known as Forsteo – stimulates the creation of new bone.
Until now, attempts to combine these approaches have not been successful.
But the latest trial found women given combination therapy had greater improved bone density than those receiving denosumab alone.
After 12 months of using the combination of the two drugs, the results were unprecedented, according to a report published in Online First in The Lancet.
In the study, a team from Massachusetts General Hospital in Boston randomly assigned 94 post-menopausal women with osteoporosis to treatment with either teriparatide taken as a daily pill, or a six-monthly jab with denosumab, or both drugs for 12 months.
The researchers measured density changes in lumbar spine, hip bone, and femoral neck using low-dose x-rays and bone biomarkers.
Readings were taken at the beginning of the trial, and at three, six and 12 months. The combination therapy was found to be significantly better than either drug alone at improving bone density.
After just one year, bone density in the femoral neck improved by 4.2 per cent, and by almost 5 per cent at the hip.
These findings were greater than previously reported for any approved treatment.
Lead author Benjamin Leder said: ‘While additional studies are needed, the results suggest that this combination may prove to be an effective osteoporosis treatment in women at especially high risk of fracture.’
Richard Eastell, director of the Mellanby Centre for Bone Research and Jennifer Walsh from the University of Sheffield, said there were doubts whether the combination would remain effective beyond a 12-month period.
‘The safety of this combination therapy also needs to be explored, as does what happens when teriparatide is stopped, as the licence only supports use for a maximum of 24 months,’ they said.
Sarah Leyland, of the National Osteoporosis Society, warned: ‘More research will be needed to ensure they are safe and effective in reducing osteoporotic fractures. Giving drugs together will also have cost implications.’