Evolocumab treatment reduces carotid intima-media thickness in paediatric patients with heterozygous familial hypercholesterolaemia.

Aim: Children with heterozygous familial hypercholesterolaemia (HeFH) show greater carotid intima-media thickness (cIMT). Evolocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor monoclonal antibody, substantially reduced low-density lipoprotein cholesterol (LDL-C) and modestly reduced lipoprotein(a) in children with HeFH. We investigated evolocumab's effect on cIMT progression.

Methods: HAUSER-RCT was a randomised, placebo-controlled trial. 157 paediatric patients with FH (age: 10-17 years) and LDL-C >130mg/dL despite statin therapy received monthly evolocumab 420mg or placebo for 24 weeks. Patients who continued into an open-label extension (HAUSER-OLE; n=150) received 80 weeks of monthly evolocumab plus statins. cIMT was measured by B-mode ultrasound scanning of right and left common carotid artery at baseline; week 24 of RCT [day 1 OLE]; and weeks 24, 48, and 80 of OLE. Descriptive analysis of cIMT was a prespecified HAUSER secondary endpoint, and inferential tests reported here were post-hoc.

Results: 151 patients had evaluable cIMT summary scores at ≥1 visit. From RCT baseline to week 24, mean cIMT increased by 0.006mm (SD=0.05) with placebo (n=37) and decreased by 0.003mm (SD=0.05) with evolocumab (n=76). From RCT baseline to OLE week 80, mean cIMT summary score decreased by 0.019mm (SD=0.04) and 0.012mm (SD=0.05), respectively, in patients who initially received placebo (n=34, P=0.007) versus receiving evolocumab throughout (n=59, P=0.067). Across patients who received evolocumab in OLE, mean cIMT significantly decreased by 0.011mm (SD=0.05) from OLE day 1 to week 80 (n=94, P=0.034).

Conclusions: In children with HeFH, evolocumab plus statin treatment up to 104 weeks led to regression in carotid arterial wall thickening.