Purpose: Patients with chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GIST) are treated with tyrosine kinase inhibitors (TKI), namely, imatinib, nilotinib, and dasatinib. Recent studies suggest that TKI therapy may be linked to the development of an acute kidney injury (AKI) and chronic kidney disease (CKD). This review evaluates current monitoring procedures at the Cincinnati VAMC.
Methods: A retrospective chart review using the electronic medical record was used to identify patients receiving TKI therapy ≥ 1 year with a diagnosis of CML or GIST. Demographics collected include: age, gender, baseline and subsequent serum creatinine, comorbid conditions possibly confounding kidney dysfunction, and receipt of nephrotoxic agents. The average change in renal function for the duration of treatment as well as per year of therapy with TKI and average number of days between lab draws were calculated.
Results: Forty-two patients were identified with active prescriptions for a TKI between January 1, 2005 and December 31, 2014. Twenty-four patients were included, of which 22 did not receive a basic metabolic panel at the recommended interval based on VA PBM Guidance. The average time between lab draws was 114 days. Fifteen patients incurred an acute kidney injury. The average change in serum creatinine for the duration of treatment was a +0.29 mg/dL. Five patients were identified that met manufacturer renal dosing criteria. Of these patients, 2 had an appropriately adjusted dose. Two patients developed CKD during the treatment period who did not have CKD at baseline.
Conclusion: Current monitoring of renal function at the Cincinnati VAMC is not in compliance with VA PBM recommendations for patients receiving TKI therapy. However, they are in line with manufacturer recommendations. While a large portion of patients developed an AKI with therapy, direct causation cannot be established as several of these patients received nephrotoxic agents in the immediately preceding 7 days of the elevated serum creatinine value. The increase in serum creatinine does not appear to be sustained, as the average change in serum creatinine for the duration of therapy was not large. Thus, quarterly monitoring of renal function appears to be appropriate in this population.