Teriparatide
The first bone-building osteoporosis drug, approved since 2002. Reduces vertebral fracture substantially and is one of the best-characterised anabolic agents in medicine.
Bone & Muscle
Abaloparatide
An approved daily injection for osteoporosis that builds new bone rather than slowing its loss. Phase 3 showed a large reduction in vertebral fracture.
Overview
Most osteoporosis drugs work by slowing the cells that break bone down. Abaloparatide does the opposite — it stimulates the cells that build bone. The trick is timing: a brief daily spike of PTH-type signalling favours bone formation, while a continuously high level would favour bone loss. Given once a day it produces the spike, not the plateau.
A 34-amino-acid analogue of parathyroid hormone-related protein, PTHrP(1-34), with substitutions conferring stability and a binding preference for the RG conformation of the PTH1 receptor over the R0 conformation. The shorter R0 residence time relative to teriparatide produces a more transient signal, proposed to favour anabolic over resorptive activity and to produce less hypercalcaemia. ACTIVE demonstrated an 86% relative reduction in new vertebral fractures over 18 months versus placebo, with significant reductions in nonvertebral fracture.
Research areas
OsteoporosisBone formationFracture prevention
Dosing reported in the literature
Every protocol below is reproduced from a published study or approved labelling, with its source named. These are records of what was studied — not recommendations, and not a suggestion that any of them is appropriate for any person.
| Protocol as reported | Source |
|---|---|
| 80 mcg subcutaneously once daily into the periumbilical regionRotate the injection site. First doses should be taken where the person can sit or lie down, because of orthostatic hypotension. | Approved product labelling |
| 80 mcg daily for 18 months followed by alendronate in the extension studyAnabolic gains are lost without a subsequent antiresorptive, which is why sequencing matters. | ACTIVE / ACTIVExtend, JAMA 2016 |
Trial status
Phase 3 ACTIVE and ACTIVExtend completed and published.
Reported safety signals
- Orthostatic hypotension and dizziness can occur in the first few hours after a dose.
- Hypercalcaemia and hypercalciuria occur, though less than with teriparatide; it should not be used where baseline hypercalcaemia exists.
- A rodent osteosarcoma signal drove a historical boxed warning for this drug class; the human boxed warning has since been removed but cumulative-use limits remain.
- Bone gains reverse after stopping unless followed by an antiresorptive agent.
Common questions
How does abaloparatide differ from teriparatide?
Both activate the PTH1 receptor, but abaloparatide favours a receptor conformation with shorter signalling duration. In practice that means a similar anabolic effect with somewhat less hypercalcaemia. No trial has established that one prevents fractures better than the other.
Primary sources
- 01
Effect of abaloparatide vs placebo on new vertebral fractures in postmenopausal women with osteoporosis: a randomized clinical trial
- 02
Effects of abaloparatide-SC followed by alendronate on fracture risk reduction in postmenopausal women with osteoporosis
- 03
Tymlos (abaloparatide) prescribing information
Medical disclaimer
This page is for informational and research purposes only. Nothing here constitutes medical advice. The compounds discussed are research chemicals. Consult a qualified clinician before starting any protocol.
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