Study Reveals Romosozumab, Denosumab Effectively Treats RA Complicated with Osteoporosis

Treatment with romosozumab or denosumab among patients with either primary osteoporosis or rheumatoid arthritis (RA) complicated with osteoporosis (RA-OP) demonstrated clinical efficacy over separate 12-month treatment periods, according to a prospective cohort study presented at the 2024 European Congress of Rheumatology (EULAR).¹ Investigators believe these treatments have the high potential to be important options in the treatment of RA-OP.

“Romosozumab, a monoclonal antibody that binds sclerostin, increases bone formation and decreases bone resorption,” wrote lead investigator Yasuhide Kanayama, MD, PhD, associated with the Department of Orthopedic Surgery and Rheumatology at Toyota Kosei Hospital, in Japan. “Although it is a novel therapeutic agent for osteoporosis, [it] has shown high effects of increasing bone density and inhibiting fragile fracture in overseas clinical trials. However, the clinical efficacy for RA complicated with osteoporosis is unknown.”

To assess the clinical efficacy of the drugs in patients with RA-OP compared with primary osteoporosis, investigators included patients with RA diagnosed according to the American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) criteria.

A total of 12 patients with RA-OP and 19 patients with primary osteoporosis were included in the trial. Eligible patients met ≥ 1 of the following criteria: a bone mineral density T-score of ≤ -2.5 at the lumbar spine or total hip and ≥ 1 moderate or severe vertebral fractures or ≥ 2 mild vertebral fractures.

All patients received romosozumab 210 mg monthly between April 2019 and July 2020. After 12 months of treatment, patients were then switched to denosumab. All patients were given native or activated vitamin D.

Investigators assessed increases and decreases in bone mineral density of the lumbar spine and total hip using DEXA and bone turnover markers, tartrate-resistant acid phosphatase form 5b (TRACP-5b), and intact n-terminal propeptide type I procollagen (P1NP).

All eligible patients were female. At baseline, the RA-OP group had a mean age of 71.4 ± 7.9 years, a mean body mass index (BMI) of 19.4 ± 2.6, and the median Fracture Risk Assessment Tool (FRAX) was 36.0 ± 14.9. In the primary osteoporosis group, the mean age was 74.3 ± 8.9 years, the BMI was 19.8 ± 3.6, and the FRAX was 32.7 ± 16.4. Previous fracture was reported in 31% of the RA-OP cohort and 70% of the primary osteoporosis cohort.

Among the RA-OP and primary osteoporosis groups, the P1NP was 62.4 ± 32.1 and 85.8 ± 94.1, respectively, and the TRACP-5b was 467 ± 228 and 542 ± 272, respectively.

In the RA-OP group, disease duration at baseline was 14.7 ± 15.7 years; C-reactive protein (CRP) was 1.99 ± 2.98; the Disease Activity Score-28 for Rheumatoid Arthritis with CRP (DAS28-CRP) was 3.60 ± 1.45; and the Health Assessment Questionnaire (HAQ) was 1.56 ± 0.99.

The rate of increased lumbar spine bone mineral density (LS-BMD) from baseline to 6, 12, 18, and 24 months in the RA-OP cohort were 11.2%, 15.5%, 19.3%, and 20.3%, respectively. Similarly, rates of LS-BMD in the primary osteoporosis group were 11.1%, 16.5%, 22.4%, and 22.4%, respectively. In the RA-OP group, the rates of the total hip BMD (TH-BMD) were 4.1% at month 6, 6.2% at month 12, 8.9% at month 18 and 9.2% at month 24. In the primary osteoporosis group, increases in TH-BMD were 2.9% at month 6, 6.5% at month 12, 7.9% at month 18 and 9.0% at month 24.

References

1. ^{Kanayama Y, Maeda M. Clinical Efficacy of Sequential Treatment After Romosozumab in Patients with Rheumatoid Arthritis Comparison with Primary Osteoporosis for 24 Months. Presented at: EULAR. Vienna, Austria. June 12 – 15, 2024.}