Romosozumab (Evenity): The Newest Dual-Action Drug for Bone Formation
Romosozumab (brand name Evenity) was approved by the U.S. Food and Drug Administration (FDA) in April 2019 for the treatment of osteoporosis in postmenopausal women who are at a very high risk of fracture. Its mechanism of action is unique because it works in two ways: it increases new bone formation while simultaneously decreasing bone resorption. This dual effect is achieved by targeting and blocking a protein called sclerostin, which naturally inhibits bone creation.
How Romosozumab is Administered
- Treatment course: The medication is given as two separate subcutaneous (under the skin) injections once a month for a limited duration of 12 months.
- Combination therapy: The bone-building effects of Romosozumab wane after 12 months. To maintain the gains in bone mineral density and reduce fracture risk, patients must transition to a different class of osteoporosis medication, such as an antiresorptive agent like a bisphosphonate or denosumab.
- Supervised injection: The two monthly injections are typically administered by a healthcare professional at a clinic visit.
Important Safety Considerations
Romosozumab has a boxed warning due to an increased risk of serious cardiovascular events, including heart attack and stroke. Therefore, it is generally not recommended for women who have had a heart attack or stroke within the previous year. Other, rare but serious side effects include osteonecrosis of the jaw and atypical femur fractures.
Recent Developments: Interchangeable Denosumab Biosimilars in 2025
While not a new class of drug, the introduction of biosimilars is a major recent development in the treatment of bone loss. In 2025, several biosimilars for denosumab (the active ingredient in the brand-name drugs Prolia and Xgeva) received FDA approval. These interchangeable biosimilars are designed to have the same safety and effectiveness as the original reference product, offering potentially more affordable treatment options.
Examples of New Biosimilars
- Jubbonti (denosumab-bbdz): An interchangeable biosimilar for Prolia, approved in March 2024, with major insurers recognizing its interchangeability starting in September 2025.
- Stoboclo (denosumab-bmwo): Approved in early 2025, this biosimilar also references Prolia and is commercially available in the U.S..
- Bildyos (denosumab-nxxp): Another biosimilar for denosumab that was approved by the FDA in September 2025.
Comparison of Osteoporosis Medications
Feature | Romosozumab (Evenity) | Denosumab (Prolia/Biosimilars) | Alendronate (Fosamax) |
---|---|---|---|
Drug Class | Anabolic (sclerostin inhibitor) | Antiresorptive (monoclonal antibody) | Antiresorptive (bisphosphonate) |
Mechanism | Increases bone formation & decreases resorption | Decreases bone resorption | Decreases bone resorption |
Administration | Subcutaneous injection | Subcutaneous injection | Oral tablet |
Frequency | Monthly for 12 months | Every 6 months | Weekly or daily |
Follow-up Therapy | Required (antiresorptive) | Often indefinite or requires transition | May have 'drug holiday' period |
Dual-Action | Yes | No | No |
Cost | High (initial list price), manufacturer programs available | Moderate to High (biosimilars reduce cost) | Low (generic available) |
Cardiovascular Risk | Boxed warning for increased risk | No boxed warning | Low risk |
Experimental and Non-Drug Treatments
Beyond new drug approvals, the field of bone health is seeing other innovations:
- Osteoboost Wearable Device: Approved by the FDA in May 2025, Osteoboost is a non-drug, prescription wearable device for postmenopausal women with osteopenia. It delivers calibrated vibrations to the hips and spine, helping to slow bone density loss through mechanical stimulation. This creates a new, non-pharmacological treatment category.
- Maternal Brain Hormone (CCN3): In November 2024, researchers identified a molecule called CCN3 that increases bone density. This discovery, stemming from studies in mice, has the potential for future therapies that actively regenerate bone, offering a promising new research path for osteoporosis and other bone conditions.
- Eladynos: An experimental oral medication that is still in clinical trial stages, aiming to offer another alternative therapy for osteoporosis.
Weighing Your Options
With the expansion of treatment options for bone loss, patients have more choices than ever before. Romosozumab provides a powerful, initial anabolic therapy for those at highest risk, particularly with recent fractures. The arrival of biosimilars for denosumab makes another effective option more accessible and potentially more affordable. For patients seeking non-drug alternatives, the Osteoboost device offers a novel approach, while ongoing research hints at future breakthroughs. Selecting the most suitable treatment depends on an individual's specific fracture risk, medical history, lifestyle factors, and budget.
Conclusion
For those asking "What is the new drug for bone loss?", the answer includes Romosozumab (Evenity), an innovative monthly injectable approved in 2019 that builds new bone and reduces resorption. Additionally, several interchangeable biosimilars for Prolia (denosumab) were approved and launched in 2025, offering more accessible options. Other novel therapies like the Osteoboost wearable and research into molecules such as CCN3 further diversify the treatment landscape. Given the complexities and potential side effects associated with different therapies, a thorough discussion with a healthcare provider is essential to create a personalized treatment plan for managing bone loss effectively.