Trial Assessing Long Term USe of PCSK9 Inhibition in Subjects With Genetic LDL Disorders

This phase 2/3 open-label extension study was designed to characterize the safety and tolerability of long-term administration of evolocumab to adults and adolescents with severe FH (HoFH or non-HoFH severe FH). Participants not on lipid apheresis at enrollment or within the prior 8 weeks initiated treatment with evolocumab 420 mg once monthly (QM). Participants on lipid apheresis at enrollment initiated treatment with evolocumab 420 mg once every 2 weeks (Q2W). Dose frequency changes (420 mg QM vs 420 mg Q2W) were permitted at week 12, 24, or other visits with Sponsor approval. Participants with \< 5% LDL-C reduction from baseline and serum unbound proprotein convertase subtilisin/kexin type 9 (PCSK9) \< 100 ng/mL could discontinue evolocumab. If serum unbound PCSK9 was ≥ 100 ng/mL with QM dosing, the participant could switch to evolocumab 420 mg Q2W treatment. Participants on apheresis with ≥ 5% LDL-C reduction from baseline and serum unbound PCSK9 \< 100 ng/mL with Q2W treatment could switch to QM dosing. Participants were to continue to receive open-label evolocumab for up to 5 years or until evolocumab became commercially available in the relevant patient population, whichever occurred first.