Hemodiafiltration and plasma levels of axitinib in a patient with metastatic renal clear cell carcinoma.

Background. The standard treatment for metastatic renal cancer is based on vascular endothelial growth factor (VEGF) and mammalian target of rapamycin (mTor) inhibitors. Compared to other advanced tumors, the treatment of renal cancer is highly affected by impaired renal function; therefore, patients with severe renal insufficiency, including patients on hemodialysis, are generally excluded from clinical trials. Case report. In the present manuscript we present the case of a renal cancer patient who underwent bilateral nephrectomy and received two lines of treatment. We hypothesized that axitinib, a tyrosine kinase inhibitor, would have a similar plasma concentration to patients without hemodialysis and that the levels before and after hemodiafiltration will not differ significantly, as observed in other targeted therapies. Conclusion. The observed axitinib concentrations were at least an order of magnitude lower than expected based on the literature and measurements in other patients. The present case report indicates a potential risk of axitinib underdosing in patients on hemodiafiltration with the standard dose; therefore, drug dosage may need to be corrected based on the plasma levels of axitinib.