PCSK9 inhibitor reduces LDL-c in pediatric HeFH patients

HAUSER-RCT Evolocumab in Pediatric Patients With Heterozygous Familial Hypercholesterolemia

Presented at the ESC congress 2020 by Raul Santos (Sao Paulo, Brazil)

Introduction and methods

FH is characterized by increased low-density lipoprotein cholesterol (LDL-c) from birth and associated with increased risk of premature ASCVD. Early onset of lipid-lowering therapy in pediatric patients not only reduces the progression of the development of subclinical ASCVD, but also may prevent clinical manifestations of the disease in early adulthood. However, many FH patients do not achieve recommended LDL-c levels even with the use of standard lipid-lowering therapies, such as statins or ezetimibe.

Evolocumab reduces LDL-c levels between 55%-60% in FH and non-FH populations with hypercholesterolemia. However, evolocumab has not been tested in pediatric heterozygous FH (HeFH) patients.

The HAUSER-RCT is a multi-center, double-blind, randomized study that tested the effect of evolocumab (420 mg/month) in comparison with placebo in pediatric HeFH patients (10-17 years of age). Follow-up was 24 weeks. The cohort (n=158) was randomized in a 2:1 fashion (evolocumab group: n=104, placebo: n=53). All participants were on a low-fat diet, lipid-lowering medication (stable LDL-c for ≥4 weeks) and a l fasting LDL-c level of ≥130 mg/dL. Primary objective was the mean relative reduction of LDL-c from baseline to week 24 in comparison with placebo. Secondary objectives were mean relative change in LDL-c from baseline to week 22 and 24, and the absolute change in LDL-c from baseline to week 24 with evolocumab treatment compared to placebo.

Main results

• Baseline LDL-c levels were 183.0 (47.2) mg/dL in the placebo group and 185.0 (45) mg/dL in the evolocumab group.
• The primary endpoint of least square mean % change was -38.3% (-45.5%--31.1%) (P<0.0001).
• Secondary endpoints showed that the mean % change in LDL-c with evolocumab vs. placebo from baseline to week 22 and 24 was -42.1% (-48.3% to -35.8%) (P<0.0001) and mean change in absolute LDL-c levels was -68.6 mg/dL (-83.1 to- 54.0 mg/dL) compared to placebo (P<0.0001).
• Least square mean % difference with evolocumab vs. placebo for lipid parameter were: -35% (-41.8%--28.3%) for non-HDL-c; -32.5% (-38.8% to- 26.1%) for ApoB; -30.3% (-36.4%to -24.%) for total cholesterol/HDL-c; and - 36.4% (-43.0% to -29.8% for ApoB/ApoA1) (all P<0.0001).
• Evolocumab in pediatric HeFH patients appeared to be safe and was well tolerated.

Conclusion

In pediatric HeFH patients, evolocumab treatment resulted in a placebo-corrected reduction of 38.3% in LDL-c levels (38.3%) and improved all secondary lipid parameters compared to placebo. Evolocumab was well tolerated and rate of adverse effects was similar to that in the placebo group.

Participants will be followed in an extension study for 2 years to further study effectiveness and safety.

- Our reporting is based on the information provided at the ESC congress -