Romosozumab (Evenity®) in Osteoporosis: When and Why It Is Used
Osteoporosis weakens the internal structure of bone and increases the risk of fragility fractures, particularly in the spine, hip, wrist and upper arm. These fractures can cause pain, loss of independence and an increased risk of further fractures.
Many established osteoporosis treatments work mainly by slowing the breakdown of bone. Romosozumab, sold under the brand name Evenity®, works differently. It can stimulate new bone formation while also reducing bone resorption.
Romosozumab is not appropriate for everyone with osteoporosis. It is a specialist treatment intended for selected people at very high or imminent fracture risk, where increasing bone strength quickly may be particularly valuable.
Treatment also requires careful cardiovascular assessment and a clear plan for what will follow the 12-month course.
What Is Romosozumab?
Romosozumab is a monoclonal antibody that targets sclerostin, a protein involved in regulating the continuous process of bone formation and breakdown.
Blocking sclerostin has two complementary effects: it increases new bone formation and reduces bone resorption. This dual action can produce a relatively rapid increase in bone mineral density at the spine and hip.
Romosozumab is sometimes described as an anabolic or bone-building treatment. Unlike teriparatide, however, it also has an antiresorptive effect.
Its UK licence is for the treatment of severe osteoporosis in postmenopausal women at high risk of fracture.
Who Might Be Considered for Romosozumab?
Romosozumab is generally considered when fracture risk is very high. This may include someone who has recently experienced a major fragility fracture, has severe osteoporosis with vertebral fractures, has sustained multiple fractures, or has other features suggesting a substantial risk of another fracture in the near future.
The decision is not made from a DEXA result alone. Previous fractures, age, bone density, falls, steroid exposure, underlying medical conditions, cardiovascular health and previous osteoporosis treatment all need to be considered.
It is also important to distinguish the treatment’s UK licence from the more specific criteria governing routine NHS funding.
NICE guidance recommends romosozumab as an NHS option for severe osteoporosis after menopause when the person is at high fracture risk and has sustained a major osteoporotic fracture within the preceding 24 months. NICE defines a major osteoporotic fracture as a fracture of the spine, hip, forearm or humerus.
These criteria reflect a situation known as imminent fracture risk: the period after a major fragility fracture when the likelihood of another fracture may be particularly high.
Romosozumab is not a routine first treatment for most people with osteoporosis. However, this does not mean that every patient must first fail several other medicines. In selected patients at very high risk, beginning with a bone-building treatment may be a deliberate specialist strategy.
How Is Romosozumab Given?
The recommended monthly dose is 210 mg. This is administered as two 105 mg injections under the skin, given one after the other at different injection sites during the same treatment visit.
The injections may be given into the abdomen, thigh or upper arm by someone trained in the injection technique.
Treatment is given once a month for 12 months. Romosozumab is not continued indefinitely, because its bone-forming effect is greatest during this initial treatment period.
If a dose is missed, it should normally be administered as soon as reasonably possible. The following dose should not be given earlier than one month after the delayed dose.
What Are the Benefits?
Clinical trials have shown that romosozumab can increase bone mineral density and reduce fracture risk in appropriately selected postmenopausal women with osteoporosis.
In very high-risk women with previous fragility fractures, treatment with romosozumab followed by alendronic acid reduced vertebral and clinical fractures more effectively than alendronic acid alone. Other research has demonstrated a substantial reduction in new vertebral fractures when romosozumab was followed by denosumab.
The important point is that romosozumab has been studied as the first part of a treatment sequence. Its benefit does not depend only on the 12 months of injections; it also depends on preserving the improvement afterwards.
No osteoporosis treatment eliminates fracture risk completely. Falls prevention, appropriate exercise, adequate nutrition, management of underlying medical problems and review of other medicines remain important.
Why Treatment After Romosozumab Is Essential
Once the 12-month course has finished, the increase in bone formation does not continue indefinitely. Without follow-on treatment, some of the improvement in bone density may be lost.
Romosozumab should therefore be followed by an antiresorptive osteoporosis treatment. Depending on the individual patient, this might be an oral bisphosphonate such as alendronic acid, intravenous zoledronic acid or denosumab.
The choice depends on kidney function, gastrointestinal history, previous treatment, fracture risk, practical preferences and whether the patient can adhere reliably to the proposed regimen.
The follow-on plan should ideally be agreed before romosozumab is started. There should be no unnecessary gap after the final monthly dose.
If denosumab is selected, its own long-term continuation and eventual stopping plan must also be considered because denosumab should not subsequently be delayed or discontinued without appropriate alternative treatment.
Cardiovascular Risk: An Important Contraindication
Romosozumab has an important cardiovascular safety warning.
In the UK, it is contraindicated in anyone with a previous myocardial infarction or stroke. This applies to any previous heart attack or stroke, not only one occurring within the past year.
For people without a previous event, cardiovascular risk still needs to be assessed. Factors such as established cardiovascular disease, high blood pressure, raised cholesterol, diabetes, smoking, severe kidney impairment and age should be considered alongside the person’s immediate fracture risk.
The reason for this caution is that one major clinical trial found more serious cardiovascular events among participants receiving romosozumab than among those receiving alendronic acid. A separate placebo-controlled trial did not show the same difference. The relationship remains uncertain, but the potential risk is sufficiently important to require careful patient selection and shared decision-making.
Romosozumab should only be used when the patient and specialist agree that the likely fracture-prevention benefit outweighs the cardiovascular risk.
Anyone who develops chest pain, sudden breathlessness, facial drooping, weakness or numbness affecting one side, or difficulty speaking during treatment should seek emergency medical help immediately. If a myocardial infarction or stroke occurs, romosozumab must be discontinued.
Calcium, Vitamin D and Kidney Function
Low blood calcium—hypocalcaemia—must be corrected before romosozumab is started. Adequate calcium and vitamin D should be maintained before and during treatment.
Blood tests may include calcium, vitamin D and kidney function. Additional investigation may be appropriate if the osteoporosis is unusually severe or there is concern about an underlying secondary cause.
No routine dose adjustment is required solely because of reduced kidney function. However, people with severe renal impairment or receiving dialysis have a greater risk of hypocalcaemia and require closer calcium monitoring.
Symptoms that can accompany significant hypocalcaemia include muscle cramps, spasms, tingling around the mouth or tingling in the fingers and toes. New or persistent symptoms should be reported.
Dental Health and Osteonecrosis of the Jaw
Osteonecrosis of the jaw has been reported rarely with romosozumab. This is a condition in which an area of jawbone does not heal normally.
The overall risk is low, but it may be increased by poor dental health, invasive dental procedures, smoking, cancer, corticosteroid treatment and previous or concurrent use of other potent osteoporosis medicines.
Patients should tell their osteoporosis specialist about existing dental problems and any planned extraction or dental surgery. Necessary dental treatment should not simply be avoided, but its timing and the individual risks may need to be discussed between the dentist and treating clinician.
Good oral hygiene and routine dental care remain important. Persistent jaw pain, swelling, a non-healing mouth ulcer or exposed bone should be assessed.
Other Possible Side Effects
The most frequently reported effects include joint pain and cold-like upper-respiratory symptoms. Headache, neck pain, muscle spasms and discomfort, redness or swelling at the injection site can also occur.
Clinically important allergic reactions are uncommon. Urgent medical attention is required for facial or throat swelling, difficulty breathing or another severe allergic reaction.
Atypical fractures of the thigh bone have also been reported rarely. New, persistent or unexplained pain in the thigh, hip or groin should therefore be mentioned to the treating team.
The existence of these uncommon risks does not mean that romosozumab is generally unsafe. It means that the potential benefits and risks must be considered for the individual patient and that important symptoms should not be ignored.
What Assessment Is Needed Before Treatment?
Before recommending romosozumab, the specialist should confirm the diagnosis and establish why fracture risk is considered very high.
This usually involves reviewing previous fractures and their circumstances, DEXA results, relevant imaging, falls, family history, steroid exposure and previous osteoporosis medication. Blood tests help identify correctable problems such as vitamin D deficiency, hypocalcaemia and some secondary causes of osteoporosis.
Cardiovascular history and risk factors must be reviewed carefully. Kidney function and dental health are also relevant.
The assessment should then consider how romosozumab compares with alternatives such as bisphosphonates, denosumab or teriparatide, and which treatment can realistically be continued after the romosozumab course.
Related information: DEXA scans and how bone-density results are interpreted
Monitoring During and After Treatment
Treatment is normally reviewed during the 12-month course to check that injections are being received on time and that there have been no significant adverse effects or changes in cardiovascular health.
Calcium may require additional monitoring in patients at increased risk of hypocalcaemia. New dental, jaw, thigh or groin symptoms should also be reported.
A repeat DEXA scan may be useful after treatment, although its timing should be individualised. The purpose is not simply to obtain a higher number: fracture history, treatment adherence and the overall clinical picture remain important.
Most importantly, arrangements for the follow-on antiresorptive treatment should be confirmed before the final romosozumab dose.
Where Romosozumab Fits in Osteoporosis Care
Romosozumab is most useful when there is a compelling reason to build bone rapidly. A recent vertebral or hip fracture, multiple vertebral fractures or severe osteoporosis combined with other major risk factors may indicate that the danger of another fracture is immediate rather than theoretical.
For patients at lower fracture risk, a bisphosphonate or another established treatment may be entirely appropriate. For those at very high risk, beginning with romosozumab and then consolidating the benefit with an antiresorptive treatment may offer a stronger strategy.
Treatment choice should therefore be driven by individual fracture risk, contraindications and the complete sequence of care—not simply by which medicine produces the largest increase in bone density.
If you have severe osteoporosis, a recent fragility fracture or uncertainty about which treatment should come next, specialist assessment can help determine whether romosozumab or another osteoporosis treatment is most appropriate. Information about private bone-health consultations is available here.
The Bottom Line
Romosozumab is a specialist osteoporosis treatment that both increases bone formation and reduces bone breakdown. It can increase bone density relatively quickly and reduce fracture risk in selected postmenopausal patients at very high or imminent risk.
It is given as two injections once a month for 12 months. Treatment must then be followed by an antiresorptive medicine to preserve the gains achieved.
Romosozumab is contraindicated in anyone with a previous heart attack or stroke. Cardiovascular risk, calcium and vitamin D status, kidney function, dental health and the long-term treatment sequence should all be considered before treatment begins.
For the right patient, romosozumab can be an important opportunity to reduce the risk of another potentially life-changing fracture. Its value depends on careful selection and on planning the entire course of osteoporosis treatment—not simply the first 12 months.
Related Reading
Understanding bone health, osteoporosis and fracture risk
Bisphosphonates for osteoporosis
Denosumab for osteoporosis and why stopping needs a plan
Trusted Patient Information
Royal Osteoporosis Society: Romosozumab
NICE: Romosozumab for treating severe osteoporosis
This article is for general information and does not constitute individual medical advice. Please speak to an appropriate healthcare professional for assessment and advice relating to your own circumstances.