Evenity (Romosozumab) Global Regulatory Status: FDA Approval, Boxed Warning, and International Access

FDA Approval: Timeline and Scope

The FDA approved romosozumab-aqqg (brand name Evenity) on April 9, 2019, under BLA 761062 for the treatment of osteoporosis in postmenopausal women at high risk for fracture [1]. High risk is defined as a history of osteoporotic fracture, multiple risk factors for fracture, or failure of or intolerance to other available osteoporosis therapy.

This approval made Evenity the first and only sclerostin inhibitor available in the United States. The FDA reviewed two Phase 3 trials as the basis for its decision: FRAME and ARCH. The FRAME trial (N=7,180) compared romosozumab 210 mg monthly to placebo in postmenopausal women with osteoporosis and demonstrated a 73% reduction in new vertebral fractures at 12 months [2]. The ARCH trial (N=4,093) compared romosozumab to alendronate and showed a 48% lower risk of new vertebral fracture at 24 months [3].

The approval path was not straightforward. An FDA advisory committee voted 18 to 1 in favor of approval in January 2019, but the cardiovascular safety signal from ARCH generated prolonged discussion [1]. The FDA's decision to approve with a boxed warning rather than reject the application reflected the committee's view that the fracture-reduction benefit outweighed the cardiovascular risk in appropriately selected patients. Treatment duration is capped at 12 monthly doses. The labeling specifies that the anabolic effect of romosozumab wanes after 12 months, and patients should transition to antiresorptive therapy afterward [1].

The Boxed Warning: Cardiovascular Risk Signal

Evenity's prescribing information carries a boxed warning, the FDA's most serious safety designation. It states that romosozumab may increase the risk of myocardial infarction, stroke, and cardiovascular death [1]. The warning instructs prescribers not to initiate romosozumab in patients who have had a myocardial infarction or stroke within the preceding year.

This warning stems from adjudicated cardiovascular event data in the ARCH trial. Among 4,093 randomized patients, 50 patients in the romosozumab group experienced a confirmed major adverse cardiovascular event (MACE) during the 12-month treatment period, compared with 38 in the alendronate group [3]. The difference was not statistically significant in the primary fracture endpoints' context, but the numerical imbalance was consistent across myocardial infarction, stroke, and cardiovascular death subcategories.

The FDA's Dr. Hylton Joffe, director of the Division of Bone, Reproductive, and Urologic Products, stated during the advisory committee meeting: "The cardiovascular signal is a concern that we believe warrants prominent labeling to ensure informed prescribing decisions" [1]. The boxed warning does not constitute a contraindication. Prescribers retain the ability to use romosozumab in patients with cardiovascular risk factors after weighing individual benefit-risk profiles. The label recommends considering whether the benefits outweigh the risks in patients with other cardiovascular risk factors and discontinuing romosozumab if a patient experiences a myocardial infarction or stroke during therapy [1].

ARCH Trial: The Study That Shaped Global Labeling

ARCH (Active-Controlled Fracture Study in Postmenopausal Women with Osteoporosis at High Risk) enrolled 4,093 postmenopausal women with osteoporosis and a fragility fracture history [3]. Patients received either romosozumab 210 mg or oral alendronate 70 mg weekly for 12 months, followed by open-label alendronate in both groups.

The fracture efficacy results were striking. At 24 months, romosozumab-to-alendronate reduced new vertebral fractures by 48% compared with alendronate-to-alendronate (6.2% vs. 11.9%; P<0.001) [3]. Clinical fractures fell by 27% (9.7% vs. 13.0%; P=0.004), and hip fractures fell by 38% (2.0% vs. 3.2%; P=0.02) [3]. No prior osteoporosis therapy had demonstrated superiority over an active bisphosphonate comparator in hip fracture reduction.

The cardiovascular findings complicated this picture. Positively adjudicated MACE events during the first 12 months occurred at a rate of 2.5% in the romosozumab group versus 1.9% in the alendronate group [3]. Several post-hoc analyses have attempted to clarify whether this signal reflects a true drug effect or confounding. A 2020 analysis published in the Journal of Bone and Mineral Research found no dose-response relationship and no mechanistic pathway linking sclerostin inhibition to atherosclerosis [4]. The FRAME trial, which compared romosozumab to placebo rather than an active comparator, did not show the same cardiovascular imbalance, with similar MACE rates in both groups [2].

FRAME Trial: Placebo-Controlled Efficacy Data

The FRAME trial (FRActure Study in Postmenopausal Women with OstEoporosis) randomized 7,180 postmenopausal women with T-scores between -2.5 and -3.5 at the total hip or femoral neck to romosozumab 210 mg monthly or placebo for 12 months, followed by denosumab in both groups [2].

At 12 months, romosozumab reduced new vertebral fractures by 73% compared with placebo (0.5% vs. 1.8%; P<0.001) [2]. Through 24 months, after both groups transitioned to denosumab, the vertebral fracture risk reduction persisted at 75% (0.6% vs. 2.5%; P<0.001) [2]. Bone mineral density at the lumbar spine increased by 13.3% from baseline with romosozumab at 12 months, compared with -0.1% with placebo [2].

Cardiovascular safety in FRAME differed from ARCH. MACE rates were 1.0% in the romosozumab group and 1.0% in the placebo group during the 12-month blinded period [2]. This parity has fueled ongoing debate about whether ARCH's cardiovascular imbalance reflects a protective effect of alendronate rather than a harmful effect of romosozumab. The Endocrine Society's 2020 clinical practice guideline on postmenopausal osteoporosis acknowledged this uncertainty, noting: "Whether the cardiovascular signal represents a risk attributable to romosozumab or a benefit attributable to alendronate remains unresolved" [5].

European Medicines Agency Authorization

The European Medicines Agency (EMA) granted marketing authorization for romosozumab on December 12, 2019, under the brand name Evenity, for the treatment of severe osteoporosis in postmenopausal women at high risk of fracture and with no history of myocardial infarction or stroke [6]. This final clause is the key difference from FDA labeling. Where the FDA's boxed warning advises against use in patients with MI or stroke within the preceding year, the EMA's indication explicitly excludes patients with any history of these events, regardless of timing.

The EMA's Committee for Medicinal Products for Human Use (CHMP) initially issued a negative opinion in June 2019, citing the cardiovascular safety concern. Amgen requested a re-examination, and a second CHMP review reversed the decision, concluding that restricting the indication to patients without any cardiovascular history adequately mitigated the risk [6]. The re-examination included additional analyses of ARCH cardiovascular data stratified by baseline risk factors.

In practice, the EMA's stricter exclusion narrows the eligible patient population more than the FDA label does. A postmenopausal woman who had an MI five years ago can receive romosozumab under FDA labeling (the boxed warning only specifically cautions against use within the preceding year) but cannot receive it under the EMA indication.

Regulatory Status Across Asia-Pacific and Canada

Japan was the first country to approve romosozumab. The Pharmaceuticals and Medical Devices Agency (PMDA) granted approval on January 8, 2019, for the treatment of osteoporosis at high risk of fracture in postmenopausal women [7]. Japan's approval preceded the FDA's by three months and reflected the PMDA's assessment that the fracture efficacy data from FRAME and ARCH justified approval despite the cardiovascular signal.

South Korea's Ministry of Food and Drug Safety approved Evenity in September 2019 for postmenopausal osteoporosis in women at high fracture risk [7]. Australia's Therapeutic Goods Administration (TGA) followed with approval in August 2020 [7]. Both regulatory agencies included cardiovascular warnings consistent with the ARCH trial findings, though the specific exclusion criteria vary by jurisdiction.

Health Canada approved romosozumab in June 2019 with labeling similar to the FDA's, including a serious warning and precaution (Canada's equivalent of a boxed warning) regarding the cardiovascular risk [8]. The Canadian label mirrors the FDA's recommendation to avoid initiation in patients with MI or stroke within the prior year, rather than adopting the EMA's lifetime exclusion.

Clinical Decision Framework: Selecting Appropriate Candidates

Regulatory restrictions create a practical screening algorithm for prescribers considering romosozumab. The 2020 American Association of Clinical Endocrinology (AACE) guideline for postmenopausal osteoporosis recommends romosozumab as a first-line option for patients at very high fracture risk, defined as those with a recent fracture (within 24 months), fractures while on approved osteoporosis therapy, multiple fractures, T-score below -3.0, or high FRAX probability [9].

Before prescribing, the AACE guideline recommends cardiovascular risk assessment [9]. The practical steps are: review the patient's history for MI, stroke, or transient ischemic attack; assess baseline cardiovascular risk factors including hypertension, diabetes, hyperlipidemia, and smoking status; and weigh whether the 12-month fracture reduction benefit justifies any incremental cardiovascular risk in that specific patient.

For patients excluded from romosozumab by cardiovascular history, teriparatide (Forteo) or abaloparatide (Tymlos) provide alternative anabolic options without cardiovascular boxed warnings. Both are parathyroid hormone pathway agents that stimulate bone formation through a different mechanism than sclerostin inhibition [5]. The tradeoff is that neither teriparatide nor abaloparatide has demonstrated superiority over bisphosphonates in hip fracture reduction, which remains a distinguishing feature of romosozumab's ARCH data [3].

Post-Market Surveillance and Ongoing Monitoring

The FDA required Amgen to conduct a post-marketing study evaluating the cardiovascular risk of romosozumab in a real-world setting as a condition of approval [1]. This study, expected to enroll patients from U.S. healthcare systems, aims to characterize MACE incidence in clinical practice where patient selection differs from trial populations.

Real-world data from the FDA's Sentinel System and other pharmacovigilance databases have begun to accumulate since 2019. A 2023 analysis of the FDA Adverse Event Reporting System (FAERS) identified cardiovascular events among romosozumab reports but found that the reporting rates were consistent with the background rates expected in a postmenopausal osteoporosis population aged 65 and older [10]. These passive surveillance data have limitations, including underreporting and lack of denominator data, but they have not triggered additional regulatory action beyond the existing boxed warning.

The EMA conducts periodic safety update reviews as part of its routine pharmacovigilance. As of 2025, no changes to the European indication or cardiovascular restrictions have been made [6]. The ongoing post-market monitoring reflects a regulatory consensus across agencies: the cardiovascular signal from ARCH warrants vigilance but has not been confirmed as a causal drug effect by subsequent data.

Label Requirements: What Prescribers Must Communicate

The U.S. prescribing information for Evenity contains several specific requirements beyond the boxed warning [1]. The Medication Guide, which pharmacies must distribute with each prescription, informs patients about the cardiovascular risk and instructs them to seek emergency medical attention for symptoms of heart attack or stroke during treatment.

The label specifies that romosozumab should be administered by a healthcare professional. Each monthly dose consists of two subcutaneous injections of 105 mg each (total 210 mg), delivered consecutively in the abdomen, thigh, or upper arm [1]. Patients should receive adequate calcium (at least 1,000 mg daily) and vitamin D (at least 600 IU daily) supplementation during treatment [1].

Contraindications listed on the FDA label include hypocalcemia (which must be corrected before initiating therapy) and known hypersensitivity to romosozumab or any component of the formulation [1]. Post-marketing reports have identified cases of hypersensitivity reactions including angioedema, erythema multiforme, and urticaria. Osteonecrosis of the jaw (ONJ) and atypical femoral fractures, class effects associated with antiresorptive agents, are listed as warnings and precautions despite romosozumab's primarily anabolic mechanism, because the drug also reduces bone resorption through secondary effects on RANKL and OPG pathways [1].

The prescribing information limits the lifetime exposure to 12 monthly doses. There are no data supporting retreatment with romosozumab, and the label does not address repeat courses [1]. After completing the 12-dose regimen, patients should transition to an antiresorptive agent such as alendronate, zoledronic acid, or denosumab to maintain the bone density gains achieved during romosozumab therapy [5].