Reduction in low-density lipoprotein
(LDL) cholesterol levels has proved to
be highly effective in reducing rates of
major cardiovascular events in numerous large
outcome trials.1-3 For this reason, LDL cholesterol
reduction has been incorporated into practice
guidelines as a fundamental means of reducing
cardiovascular morbidity and mortality.4-7
During the past 3 years, monoclonal antibodies
that inhibit proprotein convertase subtilisin–
kexin type 9 (PCSK9) have emerged as a new
class of drugs that very effectively lower LDL
cholesterol levels.8 One of the members of this
class is evolocumab, a fully human monoclonal
antibody that typically achieves approximately a
60% reduction in LDL cholesterol levels when
administered at the doses that were studied in
phase 3 trials.9-13
On completing a trial of evolocumab (parent
trial), patients could enroll into one of two longer-term
extension trials, designated Open-Label
Study of Long-Term Evaluation against LDL Cholesterol
1 (OSLER-1), for patients completing
phase 2 trials, and OSLER-2, for those completing
phase 3 trials. The OSLER-1 and OSLER-2
trials had as their primary goal the gathering of
longer-term data on safety, side-effect profile,
and LDL cholesterol reduction and also included
a prespecified exploratory analysis on adjudicated
cardiovascular outcomes. Here, we report
on the combined results of the OSLER-1 and
OSLER-2 trials