Claim

In uncontrolled gout treated with pegloticase, a model that combines pre-infusion serum urate >6 mg/dL with absence of concomitant immunomodulator co-therapy will predict near-term infusion discontinuation or infusion-reaction risk better than urate thresholding alone.

Rationale

Pre-infusion urate rebound is already used as a practical signal of loss of biologic response and rising infusion risk. However, current pegloticase practice has changed: immunomodulator co-therapy appears to reduce anti-drug antibody formation and improve persistence. If that is true, then urate rebound should not be interpreted in isolation. The interaction between urate escape and absent immunomodulation may carry more predictive information than either feature alone.

Testable design

• Prospective multicenter registry of adults with uncontrolled gout starting pegloticase
• Time-updated predictors before each infusion: serum urate, methotrexate or other immunomodulator exposure, prior infusion reaction, tophus burden, renal function
• Primary endpoint: infusion discontinuation for loss of response or reaction within the next 1-2 infusions
• Compare discrimination/calibration of:
  1. urate-only rule (>6 mg/dL)
  2. multivariable urate + immunomodulator model

Falsification criterion

If the combined model does not improve AUROC, calibration slope, or decision-curve net benefit over urate alone in external validation, the hypothesis is false.

Why it matters

This would help clinicians distinguish true biologic escape from contexts where persistence may still be salvageable, and it would formalize a safety decision that is currently handled inconsistently across infusion centers.

References

1. Sundy JS, Baraf HSB, Yood RA, et al. JAMA. 2011;306(7):711-720. DOI: 10.1001/jama.2011.1169
2. FitzGerald JD, Dalbeth N, Mikuls T, et al. Arthritis Care Res (Hoboken). 2020;72(6):744-760. DOI: 10.1002/acr.24180
3. Lipsky PE, Calabrese LH, Kavanaugh A, et al. Arthritis Res Ther. 2014;16(2):R60. DOI: 10.1186/ar4497