Background Alirocumab and evolocumab (PCSK9-Inhibitors), are new drugs incorporated into the therapeutic arsenal for the treatment of hypercholesterolaemia, having shown effectiveness and safety in the performed clinical trials.

Purpose To assess the effectiveness and safety of PCSK9-Inhibitors, to evaluate if both drugs are equally effective and to evaluate if there is any efficacy difference when using them as monotherapy agents or plus other lipid-lowering therapies (OLLT).

Material and methods Observational, retrospective and analytical study of patients in treatment with PCSK9-Inhibitors between February 2016 and August 2017. Patients’ selection, demographic and clinical parameters (sex, age, diagnosis, prescribed PCSK9-Inhibitors, OLLT, adverse events(AE)), analytical data (LDL-Cholesterol (LDL-C) and transaminases at week 0, 24 and 48) were obtained from Farmatools^® and MambrinoXXI^®.

Effectiveness was defined as the percent change in LDL-C from baseline to week 24 or 48. Safety was assessed by analysing AE andincrease in transaminases during treatment.

Effectiveness difference between groups were analysed (alirocumab vs evolocumab and PCSK9-Inhibitors vs PCSK9-Inhibitors plus OLLT) using t-test with SPSS^®v23.

Results Thirty-nine patients were included: 62% male, between 34 and 78 years’ old. Diagnosis were 77% primary hypercholesterolaemia (97% heterozygous, 3% homozygous) and 23% mixed dyslipidaemia, with mean basal LDL-C of 165.13±45.37 mg/dl. Evolocumab was prescribed in 59% of patients and alirocumab 41%. Only six patients were on PCSK9-Inhibitors monotherapy (33 plus OLLT).

The percentage change in LDL-C from baseline to week 24 were −41% and to week 48 were −61%.

The percentage change in LDL-C from baseline to week 24 in the evolocumab group were −50% and −46% in the alirocumab group (p=0.736). The percentage change in LDL-C in the monotherapy group were −36% and −51% in the group plus OLLT (p=0.283).

No EA were reported, however, 5% of patients presented elevation of transaminases at 12 weeks. There were no cases of patients requiring suspension or interruption of the treatment.

Conclusion Our study has shown a reduction in LDL-C that is comparable with that shown in clinical trials, with a greater tendency for reduction in the evolocumab group and in patients with OLLT combined, probably associated with the synergistic effect of both drugs. We must continue to study whether this is related to a reduction in morbidity and mortality.

No conflict of interest