Dual-energy CT assessment of rapid monosodium urate depletion and bone erosion remodelling during pegloticase plus methotrexate co-therapy.

Abstract

OBJECTIVES:

Pegloticase rapidly lowers serum urate in uncontrolled/refractory gout patients, with ≥1 tophus resolution in 70% of pegloticase responders and 28% of non-responders. Dual-energy computed tomography (DECT) non-invasively detects MSU deposition, including subclinical deposition, quantifies MSU volumes and depicts bone erosions. This report presents DECT findings in MIRROR open-label trial participants receiving pegloticase+MTX co-therapy.

METHODS:

Serial DECT scans were obtained during pegloticase (8 mg biweekly infusions)+oral MTX (15 mg/week) co-therapy. Bilateral hand/wrist, elbow, foot/ankle and knee images were analysed with default post-processing settings. MSU volumes were quantified and bone erosions were identified and evaluated for remodelling (decreased size, sclerosis, new bone formation). DECT and physical examination findings were compared.

RESULTS:

2 patients underwent serial DECT. Patient 1 (44-year-old male) completed 52 weeks of pegloticase+MTX co-therapy (26 infusions). Baseline examination detected 4 tophus-affected joints while DECT identified 73 MSU-affected joints (total MSU volume: 128.76 cm3). At end-of-treatment, there were no clinically-affected joints and 4 joints with DECT-detected MSU deposition. MSU volume decreased by 99% and bone erosion remodelling was evident. Patient 2 (51-year-old male) had 10 weeks of therapy (5 infusions), discontinuing because of urate-lowering response loss. Baseline examination detected 7 tophus-affected joints while DECT identified 55 MSU-affected joints (total MSU volume: 59.20 cm3). At end-of-treatment, there were 5 clinically affected joints and 42 joints with DECT-detected MSU deposition. MSU volume decreased by 58% and bone erosion remodelling was evident.

CONCLUSION:

DECT detected subclinical MSU deposition and quantified changes over time. Rapid tophus resolution and bone erosion remodelling occurred during pegloticase+MTX co-therapy.

TRIAL REGISTRATION:

ClinicalTrials.gov, https://clinicaltrials.gov, NCT03635957.

• Authors: Nicola Dalbeth, Fabio Becce, John K Botson, Lin Zhao, Ada Kumar
• Journal: Rheumatology (Oxford, England) (Rheumatology (Oxford)) Vol. 61 Issue 12 Pg. 4898-4904 (11 28 2022) ISSN: 1462-0332 [Electronic] England
• PMID: 35293984 (Publication Type: Case Reports, Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © The Author(s) 2022. Published by Oxford University Press on behalf of the British Society for Rheumatology.

Chemical References

• Uric Acid
• Pegloticase
• Methotrexate

Topics

• Male
• Humans
• Adult
• Middle Aged
• Uric Acid
• Methotrexate (therapeutic use)
• Tomography, X-Ray Computed
• Gout (drug therapy)
• Arthritis, Gouty