Author: Hyoeun Ashley Kang, PharmD Candidate 2022, UMKC School of Pharmacy
Mentor: Annie Ungerman, PharmD, BCPS; Clinical Lead Pharmacist, Rheumatology Truman Medical Centers
Romosozumab subcutaneous injection was approved by the U.S. Food and Drug Administration (FDA) in April 2019 for osteoporosis in postmenopausal women who are at high risk of fracture.Osteoporosis is a common disease state in women and affects more than 10 million individuals in the United States.1 Among multiple risk factors for developing osteoporosis, glucocorticoid (GC)-induced osteoporosis is the most common cause of secondary osteoporosis. Long-term use of GC therapy reduces bone formation and can trigger significant bone loss. In rheumatology clinics, GC medications are frequently prescribed for the treatment of rheumatoid arthritis (RA).2 Lee et al. showed that the incidence of osteoporosis is 1.9 times higher in patients with RA than without.3 Romosozumab is not mentioned in the American College of Rheumatology (ACR) Glucocorticoid-induced Osteoporosis guideline as it was last updated in 2017.
Risk of Glucocorticoid-induced Osteoporosis
Mechanism of Action
Romosozumab is an agent that has a different mechanism of action to stimulate bone formation than other osteoporosis treatments. Romosozumab is a monoclonal antibody that inhibits the action of sclerostin protein, which is a regulatory factor to block bone formation.Romosozumab is the first agent with a dual effect that increases bone formation (osteoblastic activity) and decreases bone resorption (osteoclastic activity).1,7
Dosage and Administration
The recommended dose of romosozumab is 210 mg by subcutaneous injection every four weeks for a total of 12 months. A healthcare professional should administer it as two separate injections of a 105 mg/1.7 mL syringe on the same day. The recommended injection sites of administration are abdomen, thigh, or upper arm. Additionally, patients should be on daily calcium and vitamin D supplements while taking romosozumab. If a dose is missed it is recommended to administer as soon as possible and reschedule subsequent doses from the date of the last dose.Use after 12 months is not advised as the effect of bone formation wanes after 12 doses.1,7
The most common side effects of romosozumab are arthralgia (8% to 13%), hypersensitivity reaction (7%), and headache (5% to 7%).10 Romosozumab has a black boxed warning that it can increase the risk of stroke, myocardial infarction (MI), and cardiovascular death. Thus, romosozumab should not be used in patients who previously have had an MI or stroke within the past year.7,10 The data for the Major Adverse Cardiac Events (MACE) from the ARCH trial (2017) are analyzed in Table 3.
Romosozumabis the first monoclonal antibody agent designed to target sclerostin protein. The ARCH trial and STRUCTURE trial demonstrated the efficacy and safety of romosozumab versus active comparator agents. This novel pathway of romosozumab provides an important treatment option for osteoporosis in postmenopausal women who are at high risk of fracture.