Bone Findings With Pegloticase Among Transplant Recipients With Gout

At the National Kidney Foundation Spring Clinical Meetings 2025, researchers will report bone-related findings from the PROTECT trial of pegloticase. Their study examined bone health at 24 weeks in a subset of immunosuppressed kidney transplant recipients with uncontrolled gout.

Eight patients had dual-energy CT (DECT) scans. All of them were more than 1 year post transplant, had an estimated glomerular filtration rate (eGFR) of 15 mL/min/1.73 m² or greater, and were men. Their mean (±SD) age was 52.3±11.2 years and time from transplant was 18.7±6.9 years. Mean eGFR was 45.6±12.4 mL/min/1.73 m², mean serum urate was 10.4±2.1 mg/dL, and mean flare rate was 5.3±4.6 flares/6 months.

Imaging followed standard protocols, with default postprocessing for monosodium urate (MSU) identification, scanning bilateral hands/wrists and feet/ankles/knees. To interpret images and calculate scan erosion scores (additive percentage of prespecified bones), a central reader was used.

The DECT images taken at baseline revealed multiple bone abnormalities, including erosion of more than 10% in the feet and ankles of 3 patients. Of 6 patients who received pegloticase, 4 met the imaging criteria of screening V_MSU less than 0.5 cm³ in one imaged region. At week 24, all 4 of these patients experienced sustained reductions in serum urate and V_MSU reduction (mean change in V_MSU, –98.9%±1.7%).

Erosions that were MSU adjacent, unknown mineral deposit adjacent, and deposit independent were observed in all patients before and after pegloticase administration. Monosodium urate–adjacent erosions diminished in size in one patient with no DECT findings of osteopenia or osteomalacia.

In conclusion, DECT scans uncovered poor bone health among kidney transplant recipients with uncontrolled gout. Although pegloticase greatly resolved MSU deposits at week 24, alterations in MSU-adjacent erosions were not widespread. The authors posited that this may be due to underlying chronic kidney disease–related demineralization.

Source: Marder B, Dalbeth N, Abdellatif A, Botson J, Kumar A, Becce F. Dual-energy CT bone erosion findings before and after pegloticase treatment in kidney transplant patients with uncontrolled gout: PROTECT trial. Abstract #G-575. Presented at the National Kidney Foundation Spring Clinical Meetings 2025; April 10-13, 2025; Boston, MA. doi:10.1053/j.ajkd.2025.02.576