Evenity (Romosozumab) in Adults 65 and Older: Geriatric Use and Off-Label Considerations

What Romosozumab Is and Why Age Matters

Romosozumab blocks sclerostin, a glycoprotein that normally suppresses bone formation while also upregulating bone resorption. By inhibiting sclerostin, the drug does something no other approved osteoporosis agent does simultaneously: it increases bone formation markers and decreases resorption markers within the first weeks of treatment. This dual mechanism makes it particularly attractive for the geriatric patient who has already lost substantial bone mass and needs rapid structural recovery.

The FDA granted approval in April 2019 based on data from two phase 3 trials, FRAME (N=7,180) and ARCH (N=4,093), both of which enrolled predominantly older postmenopausal women. The average age across ARCH was 74 years, meaning the on-label evidence base already reflects real-world geriatric practice [1].

How the Drug Works at a Cellular Level

Sclerostin is secreted by osteocytes and binds LRP5/LRP6 co-receptors to antagonize Wnt signaling. Without Wnt signaling, osteoblast differentiation slows sharply. Romosozumab blocks that brake. Bone formation markers, specifically procollagen type 1 N-terminal propeptide (P1NP), rise by roughly 145% above baseline within one month of the first injection [2].

The resorption side of the equation also shifts favorably. Serum C-terminal telopeptide (CTX) falls approximately 55% below baseline at one month, then gradually returns toward baseline over the 12-month treatment period. This pattern is unique; teriparatide raises both formation and resorption simultaneously, but romosozumab suppresses resorption while building bone.

Why Geriatric Patients Have a Distinct Pharmacological Profile

Older adults show no clinically meaningful difference in romosozumab pharmacokinetics compared with younger postmenopausal women in population PK analyses, according to the FDA prescribing information [3]. Renal impairment is common in this population, and while no formal dose adjustment is recommended for CrCl <30 mL/min, clinical trial data in severe renal impairment are thin. Clinicians should monitor calcium closely in anyone with GFR below 35 mL/min/1.73m², given the hypocalcemia risk that accompanies any anabolic bone agent.

FDA-Approved Use in Postmenopausal Women Over 65

Most women treated with romosozumab in clinical practice are over 65. The ARCH trial enrolled postmenopausal women with a mean T-score of -2.96 at the lumbar spine and at least one prior vertebral fracture, a population heavily concentrated in the 65-to-85 range. At 24 months, romosozumab followed by alendronate reduced new vertebral fractures by 48% compared with alendronate alone (6.2% vs. 11.9%; P<0.001) [1].

FRAME Trial: The Denosumab Sequence

In FRAME, 12 months of romosozumab followed by 12 months of denosumab produced a 75% reduction in new vertebral fractures versus placebo at 24 months [4]. Nonvertebral fractures showed a 25% risk reduction (P=0.096 in year one, a trend that requires context because the placebo arm's nonvertebral rate was lower than expected).

Hip BMD gains in FRAME averaged 6.9% at the femoral neck after 12 months, which is approximately double the gain seen with 12 months of teriparatide in head-to-head data [5].

Practical Threshold: Who Qualifies in the 65-Plus Group

The 2020 American College of Rheumatology (ACR) guideline on glucocorticoid-induced osteoporosis conditionally recommends teriparatide or romosozumab for very high-risk patients, and "very high" typically means a FRAX 10-year major fracture probability above 20% or a T-score at or below -3.0. In the 65-plus population, these thresholds are crossed frequently [6].

The Endocrine Society's 2019 osteoporosis pharmacotherapy guideline states: "For patients at very high risk of fracture, anabolic agents should be used first, followed by an antiresorptive agent to preserve gains." Romosozumab is one of only two anabolic agents in that recommendation (teriparatide being the other) [7].

Off-Label Use in Older Men With Osteoporosis

Romosozumab is not FDA-approved for use in men. Full stop. Prescribing it to a 72-year-old man with a hip T-score of -2.8 and a prior wrist fracture is off-label. Whether that off-label use is clinically justified is a separate question, and the answer is increasingly yes.

The BRIDGE Trial in Men

The BRIDGE trial (N=245) enrolled men aged 55-90 with low bone mineral density (BMD) and treated them with either romosozumab 210 mg monthly or placebo for 12 months. At 12 months, lumbar spine BMD increased by 12.1% in the romosozumab group versus 1.2% in placebo. Femoral neck BMD rose by 2.7% versus 0% [8]. No fracture endpoint data were powered in BRIDGE because the trial was too small, but the BMD gains parallel what FRAME showed in women, and BMD gains of this magnitude have historically correlated with fracture risk reduction across multiple drug classes.

Clinical Reasoning for Off-Label Male Prescribing

Men account for roughly 30% of all osteoporotic hip fractures, and one-year mortality after a male hip fracture approaches 37%, higher than the equivalent figure in women [9]. The existing approved options in men (alendronate, risedronate, zoledronic acid, denosumab, teriparatide) do not always produce adequate BMD response, particularly in men with severe osteoporosis or who have already fractured on antiresorptive therapy.

A reasonable clinical framework for off-label romosozumab in older men includes all of the following criteria before prescribing:

• Prior fragility fracture OR T-score at or below -2.5 at hip or spine
• Cardiovascular risk stratification confirming no history of MI or stroke within the prior 12 months
• Failure of, intolerance to, or clinical inadequacy of at least one antiresorptive agent
• Adequate vitamin D and calcium baseline (25-OH vitamin D above 20 ng/mL, corrected calcium within normal limits)
• Documented informed consent discussion covering the cardiovascular boxed warning and the off-label nature of therapy

This framework aligns conceptually with the ACR's very-high-risk threshold but applies it to the male patient, where approved anabolic options are limited to teriparatide alone.

Off-Label Use in Glucocorticoid-Induced Osteoporosis

Long-term glucocorticoid use suppresses osteoblast activity and accelerates apoptosis of both osteoblasts and osteocytes. The result is low-turnover bone loss that responds poorly to antiresorptive monotherapy. An anabolic agent is biologically the more appropriate first choice in this setting.

Trial Evidence in Glucocorticoid-Induced Osteoporosis

A phase 2 randomized trial (N=92) compared romosozumab with teriparatide in patients on long-term glucocorticoids (prednisolone-equivalent dose of at least 7.5 mg/day for 3 or more months). At 12 months, lumbar spine BMD increased by 9.7% with romosozumab versus 6.2% with teriparatide (P<0.001 within each arm vs. Baseline; the between-group difference favored romosozumab) [10]. The trial was not powered for fracture outcomes, and no head-to-head fracture data exist.

ACR Guideline Position

The 2022 ACR guideline update states a conditional recommendation for romosozumab or teriparatide in adults at very high fracture risk who are initiating or continuing glucocorticoid therapy at prednisone-equivalent 2.5 mg/day or higher. For geriatric patients on, say, 10 mg prednisone daily for rheumatoid arthritis, this recommendation applies directly [6].

Cardiovascular Safety in Older Adults: The Boxed Warning in Context

The cardiovascular boxed warning was added after ARCH showed a higher rate of serious cardiovascular events in the romosozumab arm versus alendronate (2.5% vs. 1.9%; absolute difference 0.6 percentage points; P=0.07). Stroke was the primary driver. FRAME, which compared romosozumab with placebo, did not show this imbalance [4].

Interpreting the ARCH Signal

The most likely explanation for the imbalance is that alendronate has a modest cardioprotective effect, not that romosozumab is directly cardiotoxic. A meta-analysis of 9 randomized trials (N=21,615) found bisphosphonate use associated with a 20-30% lower risk of cardiovascular events [11]. Romosozumab appears cardiovascularly neutral relative to placebo, but unfavorable relative to alendronate.

For the geriatric clinician, this distinction matters. A 75-year-old woman who has never had an MI or stroke, whose 10-year ASCVD risk is 18%, and who needs an anabolic agent may accept that risk in exchange for a 48% vertebral fracture risk reduction. A 78-year-old who had an ischemic stroke 8 months ago should not receive romosozumab, per the FDA labeling, which states the drug should not be used in patients who have had an MI or stroke in the preceding year [3].

Hypocalcemia Risk in Older Patients

Hypocalcemia is more common in geriatric patients because CKD, malabsorption, and vitamin D insufficiency are all more prevalent in this group. The FDA label requires adequate calcium and vitamin D supplementation before and during romosozumab therapy. In clinical practice, a pre-treatment 25-OH vitamin D level below 20 ng/mL should delay the first injection until repletion is confirmed.

Sequential Therapy After the 12-Month Course

Romosozumab's anabolic window is exactly 12 months. The BMD gains achieved during treatment are lost rapidly if no antiresorptive is started afterward, a phenomenon called the "rebound" effect that is more pronounced after romosozumab than after teriparatide.

Choosing the Antiresorptive in an Older Adult

In ARCH, the active comparator after the 12-month romosozumab course was alendronate 70 mg weekly. That sequence produced the landmark 48% vertebral fracture reduction [1]. In FRAME, denosumab 60 mg every 6 months followed the romosozumab course and produced the 75% vertebral fracture reduction at 24 months [4].

Zoledronic acid 5 mg IV annually is a reasonable alternative in patients with GI intolerance to oral bisphosphonates, which is common in older adults. A phase 2 study (N=60) showed that a single dose of zoledronic acid after 12 months of romosozumab preserved 98% of the lumbar spine BMD gain at 12 months post-transition [12].

Drug Holiday Versus Continuous Therapy

Older patients and their families often ask whether therapy can stop after one 12-month romosozumab course. It should not. Antiresorptive continuation is mandatory to prevent rapid bone loss. The ACR and Endocrine Society both specify ongoing antiresorptive therapy following anabolic treatment, with duration guided by individual fracture risk reassessment every 2-3 years [6, 7].

Monitoring Parameters in Geriatric Patients on Romosozumab

Routine clinical monitoring during the 12-month course includes:

• Serum calcium and phosphorus at baseline, one month, and three months (more frequently if CKD stage 3b or higher)
• 25-OH vitamin D at baseline; recheck at 3 months if initially insufficient
• Bone turnover markers (P1NP, CTX) at 1-3 months to confirm biological response
• Blood pressure and cardiovascular event documentation at each monthly injection visit
• Lumbar spine and hip DXA at baseline; repeat at 12 months (end of treatment) and 24 months (one year after transition to antiresorptive)

Injection Site and Administration Considerations in Older Adults

Each 210 mg dose is delivered as two simultaneous 105 mg subcutaneous injections, one in each thigh or abdomen, administered by a healthcare provider or trained self-injector. Older adults with arthritis, poor hand strength, or visual impairment may need caregiver or clinic-based administration. Monthly injection visits also provide an opportunity for falls risk assessment, which is relevant given that fracture incidence correlates directly with fall frequency in this population.

Reimbursement and Access Considerations for 65-Plus Patients

Medicare Part B covers romosozumab when administered in a physician office as a medication requiring supervision or assistance. Medicare Part D covers self-administered supply, though prior authorization is nearly universal. CMS typically requires documentation of a T-score at or below -2.5 plus a clinical note confirming high fracture risk or a prior fragility fracture. Off-label use in men faces additional denial rates; prescribers should attach BRIDGE trial data and the ACR guideline supporting very-high-risk anabolic therapy when appealing denials.

The list price for romosozumab is approximately $2,100 per monthly injection, putting the 12-month course at roughly $25,000 before payer negotiations. Amgen's Evenity co-pay assistance program can reduce out-of-pocket costs for commercially insured patients, but Medicare beneficiaries are ineligible for manufacturer co-pay cards by federal law. Patient advocacy through Medicare Part D exception requests and state pharmaceutical assistance programs is the primary cost mitigation pathway for most geriatric patients.