Short answer: Both are daily under-the-skin injections that build bone in people with osteoporosis at high fracture risk. Forteo (teriparatide 20 mcg) is a PTH analog; Tymlos (abaloparatide 80 mcg) is a PTHrP analog.12 Forteo is also approved for steroid-induced osteoporosis. Tymlos pens stay at room temperature after first use; Forteo pens stay refrigerated.
| Forteo (teriparatide) | Tymlos (abaloparatide) | |
|---|---|---|
| What it is | Parathyroid hormone analog, PTH(1-34)1 | Parathyroid hormone-related peptide analog, PTHrP(1-34)2 |
| Approved for | Postmenopausal women with osteoporosis at high fracture risk; men with primary or hypogonadal osteoporosis; men and women with osteoporosis from long-term steroid use1 | Postmenopausal women with osteoporosis at high fracture risk; men with osteoporosis at high fracture risk2 |
| Label dose | 20 mcg under the skin once a day, in the thigh or abdomen1 | 80 mcg under the skin once a day, in the abdomen around the navel2 |
| Pen | 28 daily doses; discard 28 days after first use1 | 30 daily doses; discard 30 days after first use2 |
| Storage | Refrigerated at all times except when injecting1 | Refrigerated before first use, then up to 30 days at room temperature (68°F to 77°F)2 |
| Lifetime use | More than 2 years only if fracture risk stays or becomes high again1 | More than 2 years in a lifetime is not recommended2 |
| Half-life | About 1 hour after an injection1 | About 1 hour2 |
| New spine fractures in the main trial | 5.0% vs 14.3% on placebo, median 19 months1 | 0.6% vs 4.2% on placebo at 18 months2 |
| Shared warnings | Osteosarcoma in rats; orthostatic hypotension with early doses; hypercalcemia; kidney stones1 | Osteosarcoma in rats; orthostatic hypotension; hypercalcemia; hypercalciuria and kidney stones2 |
Each label reports its own placebo-controlled trial in postmenopausal women. In the Forteo trial, 1 or more new vertebral fractures occurred in 5.0% of women on 20 mcg vs 14.3% on placebo (median 19 months).1 In the Tymlos trial, new vertebral fractures occurred in 0.6% vs 4.2% at 18 months, and nonvertebral fractures in 2.7% vs 4.7%.2
These numbers come from separate placebo-controlled trials with different people, lengths and methods, so they are not a head-to-head comparison. The women in the Forteo trial were higher risk: 90% already had a vertebral fracture at baseline, vs 24% in the Tymlos trial.12
Yes, partly. The ACTIVE trial randomized 2,463 postmenopausal women to blinded placebo, blinded abaloparatide 80 mcg or open-label teriparatide 20 mcg for 18 months. Its main comparison was abaloparatide vs placebo, not vs teriparatide. A prespecified safety comparison found hypercalcemia in 3.4% on abaloparatide vs 6.4% on teriparatide.3
More detail: Forteo side effects, Tymlos side effects, and the Forteo and Tymlos dosing schedules.