Non-Responder to Inclisiran and Evolocumab-A Female Patient with Heterozygous Familial Hypercholesterolemia and Statin Intolerance.

Despite the availability of numerous lipid-lowering agents, the treatment of lipid disorders remains a public health challenge. A substantial portion of patients, especially those with severe dyslipidemia or familial hypercholesterolemia (FH), fail to achieve the LDL-C goal. The leading causes of suboptimal LDL-C control include underprescription and poor adherence; however, in rare cases, it may result from an unusual biological response to treatment. In the presented case, a 78-year-old female with a history of transient ischemic attack and myocardial infarction was diagnosed with a heterozygous variant of FH and true statin intolerance following trials of simvastatin, rosuvastatin and pitavastatin. Initially, inclisiran was added to ezetimibe, leading to an unexpected increase in LDL-C. Due to the patient's refusal of another statin re-challenge and the unavailability of bempedoic acid, nutraceuticals were introduced. After 6 months, inclisiran was discontinued because only a 22% reduction in LDL-C was achieved, likely attributable to the nutraceutical's effect. Another PCSK9 inhibitor, evolocumab, was subsequently initiated. Shortly after the treatment onset, the patient complained of paraesthesia in the upper extremities and discontinued therapy. LDL-C levels increased by 7% after one month of treatment with evolocumab. The patient refused treatment with lipid apheresis. Possible causes of poor response to PCSK9 inhibitors include elevated lipoprotein(a) and FH.