The bone-building peptide abaloparatide produced meaningful bone density gains in 44.5% of osteoporosis patients at 18 months, versus 32.0% for teriparatide and 1.9% for placebo.
44.5% vs 32.0%Proportion of patients achieving >3% BMD gains at all three skeletal sites after 18 months — abaloparatide vs teriparatide
What the researchers found
In the ACTIVE phase 3 trial, the peptide drug abaloparatide produced significantly higher bone mineral density (BMD) response rates than both placebo and teriparatide at all time points and thresholds measured.
At 18 months, 44.5% of abaloparatide patients achieved >3% BMD gains at all three skeletal sites (total hip, femoral neck, and lumbar spine) compared to just 32.0% for teriparatide and 1.9% for placebo. The superiority was evident as early as 6 months: 19.1% of abaloparatide patients were responders versus 6.5% for teriparatide and 0.9% for placebo. Results were consistent across the >0%, >3%, and >6% response thresholds.
Why it matters
For postmenopausal women with severe osteoporosis, not just average bone density gain matters — what matters is what proportion of patients actually respond well to treatment. This analysis shows that abaloparatide produces meaningful bone density improvement in a larger proportion of patients than teriparatide (the existing peptide standard). Since abaloparatide is a 34-amino-acid peptide that selectively targets a specific conformation of the PTH receptor, it represents a next-generation peptide approach to bone building.
The numbers in context
18-month phase 3 trial · >3% BMD responders at 18 months: abaloparatide 44.5% vs teriparatide 32.0% vs placebo 1.9% · At 6 months: 19.1% vs 6.5% vs 0.9% · Measured at total hip, femoral neck, and lumbar spine
How the study worked
Prospective, exploratory responder analysis from the ACTIVE phase 3 trial (NCT01343004). Postmenopausal women with osteoporosis were randomized to abaloparatide, teriparatide, or placebo for 18 months. BMD was measured at total hip, femoral neck, and lumbar spine at 6, 12, and 18 months. Responders were defined as patients achieving BMD gains at all three sites simultaneously.
Who was studied
Postmenopausal women with osteoporosis at high risk of fracture (ACTIVE phase 3 trial)
What this study cannot tell us
This is an exploratory (not pre-specified primary) analysis of the ACTIVE trial. The responder definition requiring gains at all three sites is stringent and may not reflect clinical significance at individual sites. The trial was industry-sponsored (Radius Health, maker of abaloparatide). The study enrolled only postmenopausal women, so results may not generalize to men or premenopausal osteoporosis.
How to read the evidence
This is an exploratory analysis from a well-designed phase 3 randomized trial comparing two active treatments and placebo. Strong underlying data, though the responder analysis itself was not the pre-specified primary endpoint.
When this study was published
Published in 2019. Abaloparatide (brand name Tymlos) has been FDA-approved since 2017 and continues to be used clinically. This responder analysis remains relevant for clinical decision-making between abaloparatide and teriparatide.
The bigger picture
Abaloparatide and teriparatide are both peptide drugs that build bone by activating the PTH1 receptor, but abaloparatide does so by preferentially binding a specific receptor conformation (RG) that promotes bone building over bone resorption. This responder analysis supports abaloparatide's clinical edge and helps clinicians choose between the two available bone-building peptide options for high-risk osteoporosis patients.
Questions still open
- Does abaloparatide's higher BMD response rate translate to a greater fracture reduction advantage over teriparatide in longer follow-up?
- Would sequential therapy (abaloparatide followed by an antiresorptive) lock in the BMD gains better than teriparatide sequences?
- Can the RG receptor conformation selectivity of abaloparatide be further optimized in next-generation peptide analogs?
Common questions
What's the difference between abaloparatide and teriparatide?
Why is it important to gain bone density at all three sites?
Read the original research
Bone mineral density response rates are greater in patients treated with abaloparatide compared with those treated with placebo or teriparatide: Results from the ACTIVE phase 3 trial.
Bone, 120, 137-140
Citation
Miller, P D; Hattersley, G; Lau, E; Fitzpatrick, L A; Harris, A G; Williams, G C; Hu, M-Y; Riis, B J; Russo, L; Christiansen, C. (2019). Bone mineral density response rates are greater in patients treated with abaloparatide compared with those treated with placebo or teriparatide: Results from the ACTIVE phase 3 trial.. Bone, 120, 137-140. https://doi.org/10.1016/j.bone.2018.10.015