From the Guidelines
Prolia (denosumab) begins working immediately after injection, but its onset of action in terms of measurable effects on bone health, such as increased bone mineral density, typically occurs within 6-12 months of treatment. The medication is administered as a 60 mg subcutaneous injection once every 6 months, and patients should continue treatment as prescribed to maintain its bone-protective effects 1. Prolia works by inhibiting a protein called RANK ligand, which reduces the activity of cells that break down bone (osteoclasts), thereby decreasing bone resorption and increasing bone density. This helps reduce fracture risk in patients with osteoporosis. While working in the body immediately, the structural changes to bone that provide protection against fractures develop gradually over months of treatment. Key points to consider when using Prolia include:
- Ensuring adequate calcium and vitamin D intake, as these nutrients are essential for optimal bone health and treatment effectiveness
- Regular monitoring for side effects, particularly low calcium levels, which can be a concern, especially during initial treatment 1. It's also important to note that no dose adjustments based on age have been suggested for denosumab, unless safety issues, such as severe hypocalcaemia, develop 1.
From the Research
Onset of Action of Prolia (Denosumab)
- The onset of action of Prolia (denosumab) can be understood by examining its effects on bone mineral density (BMD) and bone resorption markers.
- A study published in 2017 2 found that denosumab treatment resulted in a significant decrease in the serum concentration of C-terminal telopeptide of type I collagen (CTX-I) by 54% at 6 months after initiation of therapy, indicating a rapid onset of action.
- Another study from 2014 3 reported that denosumab's rapid 6-month BMD increase and good safety profile contributed to improved real-life adherence of 6-monthly denosumab injections.
- The effects of denosumab on BMD were also observed in a study published in 2019 4, which found that combined treatment with teriparatide and denosumab increased spine and hip BMD more than standard combination therapy.
- A retrospective review published in 2016 5 found that noncompliance with the regular dosing regimen of denosumab did not have a clinically or statistically significant impact on BMD change over 1 year, suggesting that the onset of action of denosumab is relatively rapid and sustained.
- An update on the efficacy and safety of denosumab published in 2024 6 confirmed its potent antiresorptive effects and ability to improve BMD and reduce fracture risk in various populations.