Urine protein:creatinine ratio vs 24-hour urine protein for proteinuria management: analysis from the phase 3 REFLECT study of lenvatinib vs sorafenib in hepatocellular carcinoma

Background: Proteinuria monitoring is required in patients receiving lenvatinib, however, current methodology involves burdensome overnight urine collection. Methods: To determine whether the simpler urine protein:creatinine ratio (UPCR) calculated from spot urine samples could be accurately used for proteinuria monitoring in patients receiving lenvatinib, we evaluated the correlation between UPCR and 24-hour urine protein results from the phase 3 REFLECT study. Paired data (323 tests, 154 patients) were analysed. Results: Regression analysis showed a statistically significant correlation between UPCR and 24-hour urine protein (R2: 0.75; P < 2 × 10−16). A UPCR cut-off value of 2.4 had 96.9% sensitivity, 82.5% specificity for delineating between grade 2 and 3 proteinuria. Using this UPCR cut-off value to determine the need for further testing could reduce the need for 24-hour urine collection in ~74% of patients. Conclusion: Incorporation of UPCR into the current algorithm for proteinuria management can enable optimisation of lenvatinib treatment, while minimising patient inconvenience. Clinical trial registration: NCT01761266.