A once-a-year treatment significantly cuts the risk of broken bones caused by osteoporosis in post-menopausal women, international research has shown.
Osteoporosis rates are increasing as the population ages
Compared with a dummy pill, an infusion of Aclasta cut the risk of broken hips by 41% and of spinal breaks by 70%.
The condition accounts for 60,000 hip and 120,000 spinal fractures a year in the UK, mostly among post-menopausal women - and numbers are rising.
The study features in the New England Journal of Medicine.
The researchers say that Aclasta, known technically as zoledronic acid, could provide an alternative to other bisphosphonate drugs, which come in pill form and are taken every day, or weekly.
Compliance with these drugs is poor, partly because they can cause side effects such as inflammation of the oesophagus (food pipe), and many patients stop taking them within six months to a year.
Aclasta is administered in a drip form, but the therapy only takes 15 minutes to complete.
A total of 7,765 post-menopausal women took part in the latest trial. Half received a 5mg dose of Aclasta once a year for three years, and the rest a dummy drug.
Over the three years, 2.5% of the women in the placebo group suffered a hip fracture compared to 1.4% of the women who received Aclasta.
However, Aclasta, which costs £300 a year, was associated with a raised risk of abnormal heart rhythms.
Researcher Professor Richard Eastell, of Sheffield University, said the findings provided potential good news for thousands of women suffering from osteoporosis.
"The ability to only have the treatment once a year does mean that it simplifies the whole regimen.
"You don't have to remember every day to take this medication.
"There is no doubt that Aclasta reduces vertebral fracture, hip fracture and other breaks."
Professor David Reid, of the University of Aberdeen, led one of the UK centres involved in the study.
A disease in which the density and quality of bone are reduced, making fractures more likely
One in two women will suffer a fracture after the age of 50, mainly because of osteoporosis
On the basis of current trends, hip fracture rates in the UK may increase from approximately 46,000 in 1985 to 117,000 in 2016
He said: "Preventing hip fractures remains the holy grail of treating osteoporosis, as we know that six months after a hip fracture nearly a fifth of patients will be dead.
"Reducing hip fractures by 41% is therefore highly clinically significant."
Commenting on the study in the same journal, Professor Juliet Compston, of Cambridge University, said it was as yet unclear whether women would accept intravenous therapy in large numbers.
However, she added: "Increased treatment choices for patients are to be welcomed and may provide one means of improving adherence and treatment outcomes in osteoporosis."
The total number of women prescribed medication for osteoporosis in the UK is approximately 480,000.
However, numbers are predicted to rise as the population ages, and experts have warned this could place a significant extra burden on health services.
Novartis, which makes the drug, is currently seeking a licence for use by post-menopausal women in the UK.