Clinical Safety Outcomes in Relation to Lipoprotein(a) Concentration: Insights from the FOURIER Trial

Background: Lipoprotein(a) is believed to play a causal role in atherogenesis. Drugs are in development that directly target Lp(a) and lower levels by >75%. Thus, the safety of low Lp(a) levels is of importance. Methods: FOURIER randomized 27,564 patients w/ stable ASCVD to evolocumab (EVO) vs placebo on background statin (median f/up 2.2 y); EVO lowered Lp(a) levels by 27%. The relationships between Lp(a) levels, change in Lp(a) and 5 safety outcomes of interest based on prior reports (diabetes [DM], serious bleeding, hemorrhagic stroke, neurocognitive events, malignancy) were examined. Analyses were conducted in the overall population and by treatment arm. Multivariable models included age, sex, race, region, clinical predictors, high-intensity statin, ezetimibe, baseline hs-CRP, “Lp(a)-corrected” LDL-C, and treatment arm. Results: Lp(a) was assessed in 25,083 participants at baseline (median 37nM, range 5-1451) and 25,686 at week 12. There was no association between baseline or achieved Lp(a) levels and risk of serious bleeding, hemorrhagic stroke, neurocognitive events, or malignancy, even in the 3271 patients with Lp(a) levels ≤6nM. There was an inverse association between baseline Lp(a) levels and prevalent or incident DM [OR 1.09, 95%CI 1.07-1.12, for every 50nM lower Lp(a) below 250nM]. However, absolute change in Lp(a) with EVO was not associated with subsequent DM risk (HR 1.03, 0.91-1.16, per 50nM) and EVO did not increase the risk of DM irrespective of baseline Lp(a) (P int=0.97), even in participants in the top decile of baseline Lp(a) (HR 0.91, 0.51-1.62) in whom EVO reduced Lp(a) by 63nM. Conclusion: Lp(a) concentration and changes in Lp(a) were not associated with serious bleeding, hemorrhagic stroke, neurocognitive events, or malignancy. Levels were inversely correlated with having DM, but Lp(a) lowering over a median of 2.2 years with EVO did not further increase the risk. These findings provide new insights for ongoing trials of Lp(a)-lowering drugs.