Current treatments for the management of homozygous familial hypercholesterolaemia: a systematic review and commentary

Aims Homozygous familial hypercholesterolaemia (HoFH) is a rare disorder characterized by markedly elevated circulating low-density lipoprotein cholesterol (LDL-C) from birth. This review aimed to critically evaluate treatments for HoFH with respect to their efficacy, safety, accessibility, overall context and position within the treatment pathway.Methods and results A mixed-methods review was undertaken to systematically identify and characterize primary interventional studies on HoFH, with a focus on LDL-C reduction as the primary outcome. Interventions assessed were ezetimibe, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), lomitapide, evinacumab, with or without LDL apheresis. Twenty-six seminal studies reporting unique patient data were identified. Four studies were randomized controlled trials (RCTs) with the remainder being single-arm trials or observational registries. Data extracted were heterogeneous and not suitable for meta-analyses. Two RCTs, assessed at being low risk of bias, demonstrated PCSK9i were safe and moderately effective. A randomized controlled trial (RCT) demonstrated evinacumab was safe and effective in all HoFH subgroups. Lomitapide was reported to be efficacious in a single-arm trial, but issues with adverse events, tolerability, and adherence were identified. An RCT on ezetimibe showed it was moderately effective when combined with a statin. LDL apheresis was reported as effective, but its evidence base was at very high risk of bias. All interventions lowered LDL-C, but the magnitude of this, and certainty in the supporting evidence, varied.Conclusion In practice, multiple treatments are required to treat HoFH. The sequencing of these should be made on an individualized basis, with consideration made to the benefits of each intervention. Homozygous familial hypercholesterolaemia (HoFH) is a rare genetic disorder that results in elevated cholesterol levels, which can cause premature cardiovascular events such as heart attacks and stroke. We performed a literature review to systematically identify and analyse studies reporting on newer treatments for HoFH which lower cholesterol levels, focusing on the overall advantages and disadvantages of each treatment. We identified 26 studies, including clinical trials and observational research, reporting on the interventions ezetimibe, proprotein convertase subtilisin/kexin type 9 inhibitors, lomitapide, evinacumab, and LDL apheresis.While all treatments showed promise in reducing cholesterol levels, none were sufficient to effectively treat HoFH on their own, and often the confidence in the results were limited by the methodological weaknesses of the studies. The evidence suggests that management of HoFH requires an individualized approach, with consideration given to the efficacy, safety, tolerability, and accessibility of each treatment. Graphical Abstract The left column shows the scope of the review. In the middle column, the review process is illustrated. A schematic diagram of the summary results is provided in the right column.