FDA Approval of Abaloparatide Expands Anabolic Options for Men With Osteoporosis
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- The FDA expanded approval of daily abaloparatide injections in December 2022 to include men at high risk for osteoporotic fractures.
- Men account for nearly one-third of all hip fractures and face higher mortality rates than women following a bone injury.
- Male osteoporosis remains widely underdiagnosed because screening programs focus primarily on postmenopausal women.
- Phase 3 trial data showed significant bone density gains at the spine and hip after one year of daily treatment compared with placebo.
- Patients are instructed to take their initial doses while sitting or lying down to manage a temporary drop in blood pressure.
Table of Contents
- Expanding Bone Density Care for Men
- How Abaloparatide Rebuilds Bone Mass
- Addressing the Diagnostic Gap and Evidence Limits
- Safety Considerations and Treatment Protocols
- Closing Thoughts
Expanding Bone Density Care for Men
The FDA expanded its approval of abaloparatide in December 2022 to include men at high risk of osteoporotic fracture, closing a long-standing gap in treatment options for male bone health. Abaloparatide, sold under the brand name Tymlos, had previously been approved only for postmenopausal women.
The expansion was based on the Phase 3 ATOM (Abaloparatide Treatment of Men) trial, a 12-month randomized, placebo-controlled study of 228 men ages 40 to 85 with osteoporosis, defined by either a low bone density reading or a prior fragility fracture. Participants were randomized 2:1 to a daily 80-microgram subcutaneous injection of abaloparatide (149 men) or placebo (79 men).
After 12 months, men receiving abaloparatide had significantly greater bone density gains than the placebo group at the lumbar spine (8.48% versus 1.17%), total hip (2.14% versus 0.01%), and femoral neck (2.98% versus 0.15%), all statistically significant differences [1]. Men account for roughly 30% of all hip fractures and face a higher mortality rate than women after a fracture [2].
How Abaloparatide Rebuilds Bone Mass
Abaloparatide is a synthetic analog of parathyroid hormone-related peptide, a naturally occurring hormone involved in bone metabolism. Delivered by daily injection, it stimulates osteoblasts, the specialized cells responsible for building new bone, to form additional bone tissue in both the dense outer cortical layer and the spongy inner trabecular layer of bone.
This mechanism is anabolic, meaning it builds new bone, rather than antiresorptive, meaning it only slows the rate of bone breakdown — the mechanism behind older osteoporosis drugs. Clinicians can track early treatment response through bone turnover markers, blood tests that reflect new bone formation, with measurable changes in bone mineral density typically visible on follow-up dual-energy X-ray absorptiometry (DXA) scans within several months. Treatment is generally paired with adequate vitamin D and calcium intake.
Addressing the Diagnostic Gap and Evidence Limits
An estimated 25% of men over age 50 will experience a bone fracture related to osteoporosis during their lifetime [2]. Despite this, bone density screening guidelines are oriented primarily toward postmenopausal women, who have a clear biological screening trigger in menopause-related bone loss. Men generally lack an equivalent trigger, and clinicians often do not consider osteoporosis in male patients until after a fracture has already occurred.
The ATOM trial data support abaloparatide’s effect on bone density in men, but the study enrolled a relatively small population and followed patients for only 12 months. It was not designed or powered to measure fracture reduction directly, so longer-term data are needed to establish whether the bone density gains observed translate into a reduced risk of fracture over time [1].
Safety Considerations and Treatment Protocols
Abaloparatide’s safety profile in men is consistent with prior trials in women. The most common treatment-related side effects in the ATOM trial were injection site reactions, dizziness, nasopharyngitis, joint pain, bronchitis, elevated blood pressure, and headache [1].
Patients are advised to take their first few doses while sitting or lying down because abaloparatide can cause orthostatic hypotension, a temporary drop in blood pressure upon standing that can cause lightheadedness shortly after injection.
Prescribing guidelines limit lifetime use of abaloparatide and other parathyroid hormone analogs to two years, a precaution based on osteosarcoma — a rare bone cancer — observed in animal studies at high doses. Patients with pre-existing hypercalcemia or an elevated baseline risk of osteosarcoma should discuss alternative treatments with their physician.
Closing Thoughts
The expanded approval gives men at high risk of fracture a bone-building option that had previously been available only to postmenopausal women, addressing a documented gap in male osteoporosis care. Patients and caregivers should still consult a physician to determine whether abaloparatide is an appropriate treatment given individual risk factors and health history.
References
[1] Czerwinski, E., Cardona, J., Plebanski, R., Recknor, C., Vokes, T., Saag, K. G., Binkley, N., Lewiecki, E. M., Adachi, J., Knychas, D., Kendler, D., Orwoll, E., Chen, Y., Pearman, L., Li, Y. H., & Mitlak, B. (2022). The efficacy and safety of abaloparatide-SC in men with osteoporosis: A randomized clinical trial. Journal of Bone and Mineral Research, 37(12), 2435–2442. https://doi.org/10.1002/jbmr.4719
[2] U.S. Food and Drug Administration. (2022). Tymlos (abaloparatide) injection: Prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2023/208743Orig1s015lbl.pdf
