Efficacy of Inclisiran in Patients Having Familial Hypercholesterolemia: Heterozygous Compared to Homozygous Trait, a Systematic Review and Meta-analysis

Objective: To find out whether inclisiran sodium has different efficacy in heterozygous familial hypercholesterolemia (HeFH) and homozygous familial hypercholesterolemia (HoFH) patient groups. Methods: We conducted the systematic review and meta-analysis of ORION clinical trials. PubMed, Embase, and Clinicaltrials.gov databases were searched for the relevant studies. Atheroscalerotic parameters considered for our objective were low-density lipoprotein cholesterol, total cholesterol, proprotein convertase subtilisin/kexin type 9 (PCSK9), apolipoprotein B, and nonhigh-density lipoprotein cholesterol. Primary outcomes were the percentage difference in atheroscalerotic parameters at follow-up relative to baseline values. Our study examined these primary outcomes to determine whether there is a statistically significant difference between the HeFH and HoFH groups. Risk of bias was assessed by the Cochrane risk of bias tool. Meta-analysis was performed when at least 2 studies reported on the same variable. Results: Four ORION clinical trials provided the data related to the mean difference in the atheroscalerotic parameters at follow-up relative to baseline, of HeFH and HoFH patient populations, after administration of 300 mg inclisiran subcutaneously. We pooled together these mean differences for each group and applied a statistical test to analyze if the values were significantly different between the groups. The results of our study unveiled the significant difference in pooled mean differences in low-density lipoprotein cholesterol (HeFH: -48.62%; HoFH: -9.12%; P < 0.05), total cholesterol (HeFH: -30.31%; HoFH: -11.50%; P < 0.05), apolipoprotein (HeFH: -39.97%; HoFH: -14.68%; P < 0.05), and nonhigh-density lipoprotein (HeFH: -44.51%; HoFH: -12.22%; P < 0.05) between HeFH and HoFH groups. However, the difference in pooled mean difference in PCSK9 values (HeFH: -68.41%; HoFH: -56.25%; P = 0.2) between HeFH and HoFH groups was statistically insignificant. Studies were of high quality. Conclusions: There was a significant difference in the reductions in atherosclerotic lipid parameters in heterozygous and homozygous populations after the administration of inclisiran except for PCSK9 parameter. Further studies are needed to support this conclusion.