Evaluation of proteinuria monitoring practice patterns and treatment implications in patients with cancer receiving bevacizumab products.

Introduction: Proteinuria is a well-known toxicity of bevacizumab which can lead to kidney injury or nephrotic syndrome. There is little guidance on the frequency of monitoring and management of those that experience bevacizumab-induced proteinuria. Previous literature has suggested routine monitoring with every dose has limited clinical significance. Currently, there is no standardization of proteinuria monitoring at OhioHealth.

Methods: This retrospective descriptive study included 100 adult patients who received at least 3 doses of a bevacizumab product for a malignant condition at any OhioHealth facility from April 15, 2022 to October 15, 2022. The primary outcome was to describe the average number of proteinuria tests ordered over the course of therapy.

Results: Of the 100 patients evaluated, 91 received proteinuria monitoring during treatment with bevacizumab. The overall average number of tests completed per patient per month based on treatment period of bevacizumab was 1.51. Twenty-two of 91 patients (24%) developed grade 2+ proteinuria. Average time to first grade 2+ proteinuria event was 5.7 months. A history of baseline renal dysfunction or chronic kidney disease was the only predefined factor found to be significantly associated with developing grade 2+ proteinuria. The most common treatment modification following a grade 2+ proteinuria result was a delay in therapy.

Conclusion: Proteinuria monitoring may not be necessary for short definitive courses of bevacizumab and closer monitoring should be considered in patients with baseline renal dysfunction or CKD. Future direction includes evaluating the cost of varying proteinuria tests and developing a recommendation for OhioHealth to standardize testing.