Selpercatinib and Pseudo-Decreases in Kidney Function

This correspondence highlights how selpercatinib, a RET kinase inhibitor used in RET altered lung and thyroid cancers, may cause reversible increases in serum creatinine without true renal impairment. The authors describe a case where creatinine rose during treatment, but cystatin C levels and direct GFR measurements remained normal. They attribute the pseudo decrease in kidney function to selpercatinib’s inhibition of renal creatinine transporters MATE1 and MATE2 K. The article recommends using cystatin C as a more reliable marker of kidney function in patients receiving selpercatinib.

This correspondence highlights how selpercatinib, a RET kinase inhibitor used in RET altered lung and thyroid cancers, may cause reversible increases in serum creatinine without true renal impairment. The authors describe a case where creatinine rose during treatment, but cystatin C levels and direct GFR measurements remained normal. They attribute the pseudo decrease in kidney function to selpercatinib’s inhibition of renal creatinine transporters MATE1 and MATE2 K. The article recommends using cystatin C as a more reliable marker of kidney function in patients receiving selpercatinib.