Evenity (Romosozumab) for Women 65 and Older: What You Need to Know

What Romosozumab Actually Does in an Aging Skeleton

Romosozumab works through a mechanism no other approved osteoporosis drug uses. It inhibits sclerostin, a protein produced by osteocytes that normally puts the brakes on bone formation. By blocking sclerostin, romosozumab simultaneously increases bone formation and decreases bone resorption. This dual action is why its BMD gains come faster and larger than anything a bisphosphonate or denosumab can produce in the same time window.

For women 65 and older, this matters because the postmenopausal skeleton is already years into a resorption-dominant state. After menopause, estrogen withdrawal accelerates osteoclast activity, and by age 65 most women have lost between 30% and 50% of their peak trabecular bone mass, according to data reviewed by the National Institute of Arthritis and Musculoskeletal and Skin Diseases. Trabecular bone, the spongy interior lattice most concentrated in the spine and hip, is where fractures begin.

How Aging Changes the Sclerostin Biology

Sclerostin levels rise with age in both sexes, but the increase in postmenopausal women is steeper and more sustained than in age-matched men. A 2016 analysis published in the Journal of Bone and Mineral Research found that serum sclerostin concentrations were significantly higher in postmenopausal women compared with premenopausal controls, and that the rise correlated with years since last menstrual period rather than chronological age alone. This means the drug's target is biologically more expressed in the very women who need it most.

Bone Formation Markers: The First Signal

Within 2 weeks of the first romosozumab injection, bone formation markers like procollagen type 1 N-terminal propeptide (P1NP) rise sharply. By month 12, P1NP returns toward baseline while the bone resorption marker CTX remains suppressed. This transient anabolic window is why treatment is capped at 12 months. Trying to extend it does not extend the benefit.

The Clinical Evidence in Women 65 and Older

FRAME Trial: Spine and Hip BMD

The key FRAME trial (NCT01575834) enrolled 7,180 postmenopausal women aged 55 to 90, with a mean age of 67 years. Women received 210 mg romosozumab or placebo monthly for 12 months, then all crossed to denosumab for an additional 12 months.

Key findings at 12 months:

• Lumbar spine BMD increased by 13.3% in the romosozumab group vs. 0.0% in placebo
• Total hip BMD increased by 6.9% vs. 0.5%
• New vertebral fracture risk was reduced by 73% (relative risk reduction) at 12 months

At 24 months (after the denosumab extension), the vertebral fracture reduction was maintained at 75%. The nonvertebral fracture reduction was modest and did not reach statistical significance in FRAME, which led to further study.

ARCH Trial: Head-to-Head Against Alendronate

The ARCH trial (NCT01631214) compared romosozumab followed by alendronate against alendronate alone in 4,093 postmenopausal women with osteoporosis and a prior fragility fracture. Mean age was 74 years, making this trial more directly applicable to women in their late 60s and 70s.

The romosozumab-to-alendronate sequence reduced:

• New vertebral fractures by 48% vs. Alendronate alone at 24 months
• Nonvertebral fractures by 19% at 24 months
• Hip fractures by 38% at 24 months

These are the most clinically meaningful fracture data for geriatric women, because ARCH enrolled a higher-risk, older cohort than FRAME. The FDA prescribing information for Evenity cites both trials in its efficacy section.

What the Evidence Says About Very Old Women (Age 75+)

Subgroup analyses from FRAME and ARCH suggest that BMD gains are consistent across age subgroups, including women over 75. However, the absolute number of women over 80 in both trials was small, and fracture-endpoint power was not calculated for that subgroup. This is an honest evidence gap: the efficacy data in women over 80 is extrapolated from the broader trial population rather than directly demonstrated.

The Cardiovascular Boxed Warning: What It Means for You Specifically

This is the section you need to read carefully before any conversation with your prescriber.

In the ARCH trial, the romosozumab arm had a higher rate of serious cardiovascular events than the alendronate arm: 2.5% vs. 1.9%, a difference that was statistically significant. The events included myocardial infarction, stroke, and cardiovascular death. This finding drove the FDA boxed warning added at approval in April 2019.

The FRAME trial did not show the same imbalance, and researchers have debated whether the signal reflects a harmful effect of romosozumab or a protective effect of alendronate in that high-risk cohort. The FDA's position, stated in the boxed warning, is that romosozumab should not be initiated in patients who have had a myocardial infarction or stroke within the preceding year, and that prescribers should weigh CV risk carefully in all candidates.

Which Women 65+ Are Most Affected by This Warning

The cardiovascular warning changes the risk-benefit math most significantly for:

• Women with established coronary artery disease or peripheral arterial disease
• Women with prior stroke or TIA
• Women with poorly controlled hypertension or diabetes with end-organ damage
• Women over 75 with multiple CV risk factors

For women in this group, the standard approach is to go directly to a potent antiresorptive (zoledronic acid infusion or denosumab) rather than romosozumab, per the American Association of Clinical Endocrinology 2020 guidelines on postmenopausal osteoporosis.

Who Is a Good Candidate Despite the Warning

A 68-year-old woman with a T-score of minus 3.2 at the lumbar spine, a recent vertebral compression fracture, and no history of MI, stroke, or significant CV disease is exactly who this drug was designed for. The fracture risk in that scenario is immediate and severe. The CV risk, while real, is lower in a woman with a clean cardiovascular history.

A practical three-question framework for candidate selection:

1. Does she have a T-score at or below minus 2.5 with at least one fragility fracture, or a T-score at or below minus 3.0 regardless of fracture history?
2. Has she had a myocardial infarction or stroke in the past 12 months? (If yes, romosozumab is contraindicated.)
3. Does her FRAX 10-year major osteoporotic fracture probability exceed 20%, or hip fracture probability exceed 3%? (These thresholds, recommended by the National Osteoporosis Foundation / Bone Health and Osteoporosis Foundation, help identify who benefits most from aggressive treatment.)

If the answer to question 1 is yes, question 2 is no, and question 3 is yes, the case for romosozumab is strong.

Sex-Specific Pharmacokinetics and Dosing in Older Women

Romosozumab was studied primarily in women. The approved dose of 210 mg monthly is a dose derived from female pharmacokinetics and was not formally adjusted by body weight in clinical trials. This is worth noting because body composition shifts significantly after 65: lean mass decreases, adipose tissue increases, and renal function declines.

Population pharmacokinetic analyses included in the FDA clinical pharmacology review found that age and body weight had statistically significant effects on romosozumab exposure, but the effect sizes were not large enough to require dose adjustment. The 210 mg fixed dose produced adequate serum concentrations across the range of body weights and ages studied.

Renal impairment, common in women over 65, does not require dose modification because romosozumab is cleared primarily through the reticuloendothelial system rather than renal filtration. The prescribing information confirms no dose adjustment is needed for mild, moderate, or severe renal impairment.

Hepatic impairment also does not require dose adjustment. No formal hepatic impairment studies were conducted, which is an evidence gap, but given the clearance mechanism this is not expected to be clinically significant.

Injection Site Considerations in Older Women

Each monthly dose requires two separate 1.17 mL subcutaneous injections, typically into the abdomen, thigh, or upper arm, alternating sites. For women with reduced subcutaneous tissue or arthritis affecting hand dexterity, self-injection may be challenging. Most practices administer the injections in the clinic setting for geriatric patients.

Sequential Therapy: What Comes After 12 Months

Romosozumab is a 12-month treatment. Full stop. After that, you must transition to an antiresorptive agent or the BMD gains reverse rapidly, sometimes completely, within 12 to 24 months.

The FRAME extension data showed that denosumab following romosozumab maintained and slightly increased BMD gains at 24 months. The ARCH trial showed the romosozumab-to-alendronate sequence outperformed alendronate alone on all fracture endpoints.

Current guidance from The Menopause Society and the Bone Health and Osteoporosis Foundation recommends:

• Transitioning to denosumab (60 mg every 6 months) if CV risk permits and the woman has been unable to tolerate bisphosphonates
• Transitioning to zoledronic acid (5 mg IV annually) as the most evidence-backed option after romosozumab, especially for women who have difficulty with oral medication adherence
• Transitioning to oral alendronate (70 mg weekly) for women with no prior bisphosphonate intolerance, lower fracture risk at baseline, and preference for oral therapy

For women who received romosozumab after teriparatide (anabolic sequencing), the evidence base is thinner. A small crossover study in JBMR suggested BMD gains are still achievable when romosozumab follows teriparatide, but the magnitude may be attenuated at the spine compared to bisphosphonate-naive patients.

Conditions That Intersect With Romosozumab Use in Older Women

Osteoporosis and Fracture Risk: The Numbers

Osteoporosis affects an estimated 10.3 million Americans, of whom 80% are women. Among women over 65, the prevalence of osteoporosis at the hip or spine reaches roughly 25 to 30%. The lifetime fracture risk for a 65-year-old woman is approximately 40%, comparable to her combined risk of breast cancer, heart disease, and stroke, a statistic cited in the Bone Health and Osteoporosis Foundation's 2022 Clinician's Guide.

Prior Bisphosphonate Use

Women who have been on bisphosphonates for more than 3 to 5 years and still have T-scores below minus 2.5 with fractures are appropriate candidates for escalation to romosozumab. The concern about atypical femoral fractures (AFFs) with long-term bisphosphonates is real. A 2018 ASBMR task force report estimated AFF incidence at 3.2 to 50 cases per 100,000 person-years with bisphosphonate use, rising with duration of exposure. Switching to romosozumab offers a bisphosphonate holiday while still delivering aggressive fracture protection.

Type 2 Diabetes in Postmenopausal Women

Women over 65 with type 2 diabetes have higher fracture rates than nondiabetic peers despite often having normal or even elevated BMD, because diabetes impairs bone quality through advanced glycation end products and altered bone turnover markers. The interaction between romosozumab and diabetic bone disease has not been formally studied in a dedicated trial, which is an acknowledged evidence gap. Observational data suggest the BMD response to romosozumab is preserved in diabetic women, but fracture endpoint data specific to this population are not available.

Hypocalcemia Risk

Older women with vitamin D deficiency, which affects an estimated 41.6% of U.S. Adults and is more common in women over 65 who have reduced sun exposure and impaired skin synthesis, are at risk for hypocalcemia with any bone anabolic agent. The FDA prescribing label requires that providers pretreat hypocalcemia before starting romosozumab and ensure adequate calcium and vitamin D throughout the 12-month course. A reasonable starting point is 1,000 to 1,200 mg elemental calcium daily from diet plus supplement and 800 to 1,000 IU vitamin D3 daily, consistent with ACOG and National Academy of Medicine recommendations for women over 70.

Pregnancy and Lactation: Not Applicable at 65+, But Required Disclosure

Romosozumab is indicated only in postmenopausal women. Women 65 and older are universally postmenopausal, so pregnancy and lactation are not biologically possible. This section is included for completeness and because younger postmenopausal women using this article as background research should have access to this information.

The FDA prescribing information classifies romosozumab as contraindicated in pregnancy based on animal reproductive studies showing fetal harm at doses producing exposures below the human clinical exposure. No adequate human pregnancy data exist. The drug should not be used during lactation, as transfer into human breast milk has not been studied. No contraception requirement is listed for the geriatric indication because the population is postmenopausal by definition, but any woman under 50 being considered for off-label use would need confirmed postmenopausal status and reliable contraception throughout treatment.

Side Effects Most Relevant to Women 65 and Older

The side-effect profile shifts somewhat in older women because baseline CV risk is higher, falls are more common, and polypharmacy is prevalent.

Common side effects reported in clinical trials:

• Injection site reactions: seen in approximately 8% of women in FRAME, including erythema, pain, and bruising at the injection site
• Arthralgia and musculoskeletal pain: reported in 12% of the romosozumab group in FRAME vs. 8% in placebo
• Hypocalcemia: asymptomatic in most cases but requires monitoring, particularly in women with CKD stage 3 or worse
• Headache: reported in 6% of participants in FRAME

Rare but serious:

• Atypical femoral fractures: rare, based on postmarketing surveillance data, incidence not precisely quantified in clinical trials
• Osteonecrosis of the jaw: rare, with a higher background risk in women on concurrent oncologic bisphosphonate doses or with active dental disease
• Serious cardiovascular events: as described above, from the ARCH boxed warning

Drug interactions are limited because romosozumab is a monoclonal antibody cleared non-renally. It does not interact with CYP450 enzymes and has no known pharmacokinetic interactions with common medications used in geriatric women, including statins, ACE inhibitors, or thyroid hormone replacement.

Who This Treatment Is Right For and Who Should Choose a Different Path

Right for Romosozumab

• Postmenopausal woman aged 65 to 80 with a T-score at or below minus 2.5 plus at least one vertebral or hip fragility fracture
• Woman who has had a bisphosphonate holiday of 3 or more years due to AFF concern and still has high fracture risk
• Woman who has failed or is intolerant of bisphosphonates and cannot tolerate teriparatide's daily injections
• Woman whose FRAX score places her at very high fracture risk and who needs the fastest possible BMD recovery after a recent fracture

Not the Right Fit

• Woman with MI or stroke in the past 12 months (hard contraindication from the boxed warning)
• Woman with multiple uncontrolled cardiovascular risk factors and moderate osteoporosis where a bisphosphonate is adequate
• Woman over 80 with severe frailty, because the evidence base in that subgroup is thin and the practicalities of monthly injections and follow-up are more burdensome
• Woman who is currently being treated for hypocalcemia or who has advanced CKD (stage 4 to 5) without specialist nephrology comanagement

Monitoring During the 12-Month Course

Your prescriber should check the following before starting romosozumab and during treatment:

• Serum calcium and 25-OH vitamin D before the first injection and at clinical discretion during treatment
• Bone mineral density (DXA scan) at baseline and at the end of 12 months to document response and plan sequential therapy
• Cardiovascular risk assessment including blood pressure, history of prior cardiac events, and current cardiac medications
• Dental evaluation if there is a history of jaw problems, recent extractions, or upcoming dental surgery

No routine monitoring of romosozumab serum levels is needed or available in standard practice.

After the 12-month course, a follow-up DXA at 12 to 24 months into sequential antiresorptive therapy confirms that BMD gains are being maintained. If they are not, the choice of sequential agent may need to be reconsidered.

A Note on Cost and Access for Women on Medicare

Romosozumab costs approximately $1,800 to $2,100 per monthly dose in the United States before insurance, making the 12-month course roughly $21,000 to $25,000. For women 65 and older on Medicare, coverage falls under Medicare Part B (physician-administered) in most clinic settings. A 2022 analysis in JBMR Plus found that cost-effectiveness ratios for romosozumab were favorable for women with very high fracture risk (FRAX major osteoporotic fracture probability > 30%) but less favorable for women at moderate risk.

Prior authorization is required by most payers and typically requires documentation of a qualifying T-score, prior fracture, and often prior trial or intolerance of a bisphosphonate. Your prescriber's office should submit the prior authorization before scheduling the first injection appointment.