CalciumNEW2026

Case Report: Reopening the anabolic window - romosozumab added to ongoing denosumab for severe osteoporosis in two kidney transplant recipients.

Barbuto Simona, Mastromauro Paolo, Zavatta Guido, Vetrano Daniele et al. — Frontiers in endocrinology

Summary

This case report describes a new treatment approach for severe bone thinning (osteoporosis) in two kidney transplant patients. By adding a bone-building medication, romosozumab, to their ongoing denosumab treatment, researchers observed significant improvements in bone density, especially in the spine. This combination therapy appeared safe and effective for these specific patients, offering a potential new option for those struggling with bone loss after transplantation.

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Key points

This study explored a new treatment for severe bone thinning in two kidney transplant patients.
Adding a bone-building drug (romosozumab) to an existing bone-strengthening drug (denosumab) improved their bone density.
The combination therapy specifically strengthened the spine without causing significant side effects.
This approach might be considered for similar patients who do not respond well to standard bone treatments.

What the study looked at

What question the study asked: This study investigated whether adding a newer bone-building medication, romosozumab, could be a safe and effective strategy for kidney transplant patients with severe osteoporosis who were not adequately responding to their long-term denosumab treatment. The goal was to see if this combination could further improve bone strength and reduce fracture risk. How it was studied (design/participants): This was a case report, which means it focused on two specific female kidney transplant recipients. Both patients had severe osteoporosis and a high risk of fractures despite already receiving denosumab for an extended period. Researchers added romosozumab to their ongoing treatment for 12 months, carefully monitoring changes in their bone density, bone formation markers, calcium levels, and overall health, including kidney function. What it found: The study observed positive outcomes in both patients. Adding romosozumab led to an early increase in markers indicating new bone formation and significant improvements in bone mineral density, particularly in the lumbar spine. Importantly, their blood calcium levels, parathyroid hormone, vitamin D, and kidney transplant function remained stable, with no new fractures reported. This suggests the combination therapy was well-tolerated and effective for these two individuals.

Dietary takeaway

While this study focuses on specific medical treatments for severe osteoporosis in a very particular patient group, it underscores the importance of maintaining strong bones. For the general public, ensuring adequate calcium intake through a balanced diet, including dairy products, fortified plant-based milks, and leafy green vegetables, is crucial for bone health. However, this was a small case report involving only two patients, so these findings are not definitive and require confirmation through larger, controlled studies before being widely recommended.

Abstract

Kidney transplant recipients develop disorders of mineral and bone metabolism that further impair bone strength, leading to osteoporosis and a high fracture risk. However, evidence in this setting is limited. Romosozumab, a sclerostin inhibitor with both anabolic and antiresorptive effects, is an attractive option, but its use in transplant recipients, as well as its combination with denosumab, has rarely been reported. We describe two female kidney transplant recipients with severe osteoporosis and persistently high fracture risk despite long-term denosumab, in whom romosozumab (210 mg monthly) was added to ongoing denosumab for 12 months. In both patients the bone-formation markers P1NP and BAP rose early, and bone mineral density improved preferentially at the lumbar spine (Case 1 + 5.9%, Case 2 + 11.2%), with only modest changes at the femoral neck and total hip. Serum calcium, parathyroid hormone, 25-hydroxyvitamin D and allograft function remained stable throughout, with no clinically significant hypocalcemia, and neither patient sustained a new vertebral fracture. Adding romosozumab to ongoing denosumab thus reopened the anabolic window and improved lumbar-spine bone mineral density without compromising mineral metabolism or graft function. This combination may represent a reasonable option for carefully selected transplant recipients who continue to lose bone or to fracture despite antiresorptive therapy, pending confirmation in controlled studies.

View on PubMed →DOI: 10.3389/fendo.2026.1947545