Study Shows Denosumab Has Greater Impact on Bone Mineral Density Than Alendronate

The increase in spinal bone mineral density was significantly higher in patients treated with denosumab compared with alendronate after adjustment for bone mineral density at baseline, age, sex, and other osteoporosis risk factors.

Denosumab proved more effective than the oral bisphosphonate alendronate at raising bone mineral density of the spine in long-term glucocorticoid users over 12 months, investigators reported at the annual meeting of the American College of Rheumatology1 in November.

The study included 139 patients with an average age of 50 years who were taking long-term prednisolone (minimum dose of 2.5 mg/day for at least a year) for various medical conditions and had not previously taken denosumab or teriparatide. The average prednisolone dose at the start of the study was 5.7 mg/day. Most of the patients (81%) had systemic lupus erythematosus (SLE), 9.4% had rheumatoid arthritis, and 5% had myositis.

Participants were randomized to receive either denosumab 60 mg subcutaneously every 6 months or the oral bisphosphonate alendronate 70 mg/week. All patients also received calcium (Caltrate 3000 mg/day) and vitamin D3 (cholecalciferol 1000 IU/day). At the start of the study, the patients underwent bone mineral density testing (femoral neck, total hip, lumbar spine) and markers of bone turnover (serum P1NP and CTX) were also assayed. These tests were repeated every 6 months.

At the start of the study, more than half of the patients (53%) were osteoporotic (T score < -2.5) at the hip, femoral neck, or lumbar spine. Pre-existing fragility or vertebral fracture were evident in 14% of patients (13% had a family history of fractures), and more than half of patients had never taken bisphosphonates. Patients’ average body mass index (BMI) was 23.1 kg/m2 with 11% having a BMI of less than 18 kg/m2.

The third bone mineral density test at 12 months showed that patients treated with denosumab had experienced a significant gain in bone mineral density at the lumbar spine (+3.5±2.5%; P < 0.001) and the hip (+0.9±2.8%; P = 0.01) compared with patients treated with alendronate for whom the increases were +2.5±2.9% (P < 0.001) and +1.6±2.7% (P < 0.001) respectively.

The increase in spinal bone mineral density was significantly higher in patients treated with denosumab compared with alendronate after adjustment for bone mineral density at baseline, age, sex, and other osteoporosis risk factors (smoking, drinking, cumulative glucocorticoid doses over 1 year, BMI, menopausal status, and personal history of fracture). However, after adjusting for the same confounding factors, differences in hip and femoral neck bone mineral density were not significantly different between the 2 treatment groups after adjustment for the same confounding factors.

The frequency of adverse events was similar in both groups. Major infective episodes were uncommon, minor upper gastrointestinal symptoms, and non-specific dizziness were more common with alendronate treatment while arthralgia, minor infections (eg, upper respiratory tract), and new hypertension were more commonly reported by patients taking denosumab.

Chi Chiu Mok, MD, FRCP, from Tuen Mun Hospital, Hong Kong, China said: “In chronic glucocorticoid users, subcutaneous denosumab is superior to oral alendronate in raising the spinal bone mineral density at one year.

“Denosumab may be considered as an alternative in patients who are contraindicated or intolerant to the oral bisphosphonates in chronic glucocorticoid users.”

Reference:

Mok CC, Ho LY, Kwok KM, Tuen Mun Hospital. Denosumab versus oral bisphosphonate for osteoporosis in long-term glucocorticoid users: a 12-month randomized controlled trial. Presented at: American College of Rheumatology Convergence 2020; November 5-9, 2020; Virtual. Accessed November 8, 2020. https://acrabstracts.org/abstract/denosumab-versus-oral-bisphosphonate-for-osteoporosis-in-long-term-glucocorticoid-users-a-12-month-randomized-controlled-trial/