No Increase in Infections With Combination Denosumab and Biologic DMARDs

December 27, 2017

Concurrent use of biologic therapies for RA and osteoporosis poses no higher risk of serious opportunistic infections.

Key points
• The incidence of serious infection remains low in patients treated with biologic disease modifying anti-rheumatic drugs (bDMARDs).

• Concurrent use of the biologic drug denosumab, used to treat osteoporosis, does not increase the risk of serious opportunistic infections in patients with rheumatoid arthritis.

• It is safe to treat osteoporosis with denosumab while treating rheumatoid arthritis with bDMARDs.

Background
Both rheumatoid arthritis and agents such as glucocorticoids that are used to treat it may increase the risk of osteoporosis and bone fractures. These risks lead to many patients with rheumatoid arthritis being treated with drugs like bisphosphonates to preserve bone density.

Denosumab is a new biologic monoclonal antibody that prevents resorption of bone by osteoclast cells. Arthur Lau and colleagues1 in Ontario, Canada, point out that the same mechanism by which denosumab affects osteoclast expression may also affect cells of immunity and lead to higher rates of infection.

Some studies have shown that combining biologic treatments may increase the risk of infection. The authors sought to determine whether patients with rheumatoid arthritis and osteoporosis treated with both denosumab and a bDMARD developed more serious infections than those treated with a bDMARD alone. They recently published their findings.

The study
The authors conducted a cohort study looking at adult patients with rheumatoid arthritis who took bDMARDs both alone and in conjunction with denosumab for osteoporosis. 308 patients were included in the study with 102 in the concurrent group and 206 in the biologic-alone group.

The results
• The rate of serious or opportunistic infections was 1.22 per 100 patient-years (95% confidence interval [CI], 0.25-3.56) in the concurrent group and 0.98 per 100 patient-years (95% CI, 0.32-2.29) in the biologic-alone group (rate difference, 0.24; P = 0.77).

• Pneumonia was the most common infection observed.

• There remained no statistically significant difference between the concurrent group and the biologic-alone group when specific drugs were examined (methotrexate and prednisone).

Implications for physicians
• Physicians should feel comfortable prescribing denosumab in combination with a biologic disease-modifying drug when treating patients with rheumatoid arthritis and osteoporosis.

• Providers can reassure patients that there is no greater risk of serious infection when receiving both a bDMARD and denosumab.

Disclosures:

Amgen Inc. provided funding for this study.

References:

1. Lau AN, Wong-Pack M, Rodjanapiches R, et al. Occurrence of serious infection in patients with rheumatoid arthritis treated with biologics and denosumab observed in a clinical setting. J Rheumatol. 2017 Nov 15. pii: jrheum.161270. doi: 10.3899/jrheum.161270. [Epub ahead of print]