Teriparatide Biosimilar Shows Comparable Efficacy to Reference Drug in Postmenopausal Osteoporosis

Researchers treated postmenopausal women with osteoporosis with teriparatide biosimilar RGB-10, which improved their bone health measures and reduced fracture risk comparably to reference teriparatide. | Image Credit: mat - stock.adobe.com

Teriparatide biosimilar RGB-10 and reference teriparatide showed consistent therapeutic effects in postmenopausal women with osteoporosis at very high risk of fracture, with no significant differences observed between the 2 treatments across various bone health measures or at any assessment time point, according to a study published in Osteoporosis International.¹

Current therapeutic strategies for postmenopausal women managing osteoporosis aim to decrease fracture risk by using either antiresorptive or anabolic agents. The development of the osteoanabolic therapies teriparatide, abaloparatide, and romosozumab has recently expanded the treatment landscape.

Eli Lilly originally gained US approval for teriparatide (Forteo) in 2002 and European approval in 2003, based on results from a phase 3 study. The originator teriparatide patent expired in 2019, which spurred the development of several biosimilar compounds that have since received marketing authorization.

In January 2017, the European Medicines Agency approved the first teriparatide biosimilar products, Terrosa (Gedeon Richter) and Movymia (Stada Arzneimittel).² Theramex received approval for Livogiva in 2020, followed by Accord Healthcare for Sondelbay in 2022, and Strides Pharma Limited for Kauliv in 2023. Preclinical studies confirmed the biologics' structure, purity, and biological activity, and a randomized, double-blind pharmacokinetic/pharmacodynamic study provided further support for these approvals.¹

The current retrospective study analyzed the real-world comparative efficacy of RGB-10, a teriparatide biosimilar, and reference teriparatide in reducing osteoporosis measures among postmenopausal women with very high fracture risk. Researchers used multiple assessment methods, including dual-energy x-ray absorptiometry (DXA) and 3D-SHAPER imaging, to evaluate bone microarchitecture and fracture risk by determining bone mineral density (BMD). They also performed trabecular bone score (TBS) assessments, quantitative ultrasound (QUS), and high-resolution peripheral quantitative CT (HRpQCT) imaging of the radius and tibia.

Researchers administered both RGB-10 (n = 25) and reference teriparatide (n = 25) once a day in 20 μg subcutaneous doses for over 2 years among postmenopausal women with very high fracture risk. They found no significant differences between groups in terms of mean (SD) age (reference teriparatide, 68.4 [7.3] years; RGB-10, 68.5 [6.7] years), weight (reference teriparatide, 61.3 [10.1] kg; RGB-10, 61.2 [11] kg), or body mass index (reference teriparatide, 22.6 [2.9]; RGB-10, 22.3 [3.2]).

The study showed no significant differences between reference teriparatide and RGB-10 regarding family history of osteoporosis, tobacco use, glucocorticoid use, the incidence of diabetes mellitus and rheumatoid arthritis, prior bisphosphonate use, or the prevalence of fractures. Researchers also found no significant differences among the treatment groups at baseline for any measurement parameters assessed by DXA, 3D-SHAPER, TBS, QUS, and HRpQCT.

At 12 and 24 months of treatment, both reference teriparatide and biosimilar RGB-10 showed significant improvements from baseline in mean BMD at the lumbar spine, as measured by DXA. Researchers found no significant statistical difference between the treatment groups at any site or time point.

Both treatment groups experienced significant increases in trabecular volumetric BMD at both 12 and 24 months, with no significant differences between the groups. This technique showed no significant changes from baseline in other measured parameters for either treatment group.

RGB-10 treatment significantly increased integral volumetric BMD from baseline at both 12 and 24 months. Reference teriparatide treatment showed no statistically significant changes in integral volumetric BMD from baseline, and there were no significant intergroup differences.

Neither treatment group experienced significant changes in median TBS from baseline at 24 months. However, at 12 months, the RGB-10 group showed transient but significant improvement in TBS from baseline, without any statistically significant intergroup differences.

The RGB-10 group showed a significant increase in median QUS from baseline at 24 months, but the study found no significant differences between treatment groups in median QUS scores at either 12 or 24 months. Similarly, although some significant changes from baseline occurred at the radius and tibia at 12 and 24 months within both groups, the study observed no statistically significant intergroup differences related to treatment.

The study also found no statistically significant differences between the teriparatide biosimilar and reference teriparatide groups for any measured parameter at any timepoint. No incident fractures occurred during the treatment period.

Although the retrospective nature of this study introduced the possibility of selection bias and limited the ability to draw definitive conclusions, the observed consistency between RGB-10 and reference teriparatide across a range of bone health parameters is noteworthy.

“Real-world evidence of the clinical benefit of the RGB-10 biosimilar in high fracture risk osteoporosis patients provides clinicians and patients with a valuable therapeutic option in this vulnerable patient group,” the study authors concluded. 

References

1. Hadji P, KamaliL, ThomasiusF, Horas K, Kurth A, Bock N. Real-world efficacy of a teriparatide biosimilar (RGB-10) compared with reference teriparatide on bone mineral density, trabecular bone score, and bone parameters assessed using quantitative ultrasound, 3D-SHAPER and high-resolution peripheral computer tomography in postmenopausal women with osteoporosis and very high fracture risk. Osteoporos Int. 2024;35:2107-2116. doi:10.1007/s00198-024-07208-z
2. Biosimilar Approvals. The Center for Biosimilars®. January 7, 2025. Accessed February 14, 2025. https://www.centerforbiosimilars.com/biosimilar-approvals