Injection of an improperly stored proprotein convertase subtilisin/kexin type 9 monoclonal antibody in a patient with secondary dyslipidemia from nephrotic syndrome: a case report

Background: Elevated plasma cholesterol and/or plasma triglyceride levels in nephrotic syndrome patients are the result of impaired lipoprotein clearance and a compensatory increase in hepatic lipoprotein synthesis. Plasma proprotein convertase subtilisin/kexin type 9 levels directly correlate to the amount of proteinuria in nephrotic syndrome patients. Proprotein convertase subtilisin/kexin type 9 monoclonal antibody has been used to treat dyslipidemia in some refractory nephrotic syndrome cases. As a therapeutic protein, proprotein convertase subtilisin/kexin type 9 monoclonal antibody simply deteriorates if stored in inappropriate temperatures or conditions. Case presentation: In this article, we present the case of a 16-year-old Thai female with severe combined dyslipidemia secondary to refractory nephrotic syndrome. She received proprotein convertase subtilisin/kexin type 9 monoclonal antibody (alirocumab) treatment. However, the drugs were mistakenly frozen in a freezer for up to 17 hours before being stored at 4 °C. After using two frozen devices, serum total cholesterol, free proprotein convertase subtilisin/kexin type 9, and lipoprotein(a) significantly decreased. Nonetheless, the patient developed a skin rash 2 weeks after the second injection and the lesion spontaneously resolved without any treatment approximately 1 month later. Conclusions: The effectiveness of proprotein convertase subtilisin/kexin type 9 monoclonal antibody seems to be stable after being stored under freeze–thaw conditions. However, improperly stored drugs should be discarded to avoid any potential undesirable side effects.