Study of Alirocumab (REGN727/SAR236553) in Patients With Heterozygous Familial Hypercholesterolemia (HeFH) Undergoing Low-density Lipoprotein (LDL) Apheresis Therapy

Inclusion Criteria:

1. Men and women ≥18 years of age at the time of the screening visit

2. Diagnosis of HeFH (Heterozygous familial hypercholesterolemia)

3. Currently undergoing LDL (low-density lipoprotein) apheresis therapy QW (weekly) or Q2W (every 2 weeks) or at least 8 weeks prior to the screening visit

Exclusion Criteria:

1. Homozygous FH (familial hypercholesterolemia)

2. Background medical LMT (lipid-modifying therapy) (if applicable) that has not been stable for at least 8 weeks prior to the screening visit

3. LDL apheresis schedule/ apheresis settings that have not been stable for at least 8 weeks prior to the screening visit

4. An LDL apheresis schedule other than QW to Q2W

5. Initiation of a new exercise program or exercise that has not remained stable within 8 weeks prior to the screening visit (week -2)

6. Initiation of a new diet or a diet that has not been stable within 8 weeks prior to the screening visit (week -2)

7. Use of nutraceuticals or over-the-counter therapies known to affect lipids, at a dose/amount that has not been stable for at least 8 weeks prior to the screening visit (week -2), or between the screening and randomization visit

8. Presence of any clinically significant uncontrolled endocrine disease known to influence serum lipids or lipoproteins

9. Known history of a positive test for human immunodeficiency virus

10. Use of any active investigational drugs within 1 month or 5 half-lives of screening, whichever is longer

11. Patients who have been treated with at least 1 dose of alirocumab or any other anti-PCSK9 monoclonal antibody in any other clinical studies

12. Pregnant or breastfeeding women