Efficacy and Safety of PCSK9 Monoclonal Antibodies in Patients With Diabetes

Purpose Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are novel drugs that have proven efficacy in improving cardiovascular outcomes. Roles for the PCSK9 molecule in metabolic pathways beyond LDL receptor processing and cholesterol homeostasis are well established. PCSK9 genetic variants associated with lower LDL-C levels correlate with a higher incidence of type 2 diabetes (T2DM), calling into question the appropriateness of these drugs in patients with T2DM and those at high risk of developing diabetes, and whether cardiovascular benefit seen with PCSK9 inhibitors might be offset by resultant dysglycemia. The purpose of this review was to examine the role of PCSK9 protein in glucose homeostasis, the impact of PCSK9 inhibition in relation to glucose homeostasis, and whether some of the cardiovascular benefit seen with PCSK9 inhibitors and statins might be offset by resultant dysglycemia. Methods Comprehensive literature searches of electronic databases of PubMed, EMBASE, and OVID were conducted by using the search terms hyperlipidaemia, PCSK9, diabetes, and glucose as well as other relevant papers of interest collected by the authors. The retrieved papers were reviewed and shortlisted most relevant ones. Findings Genetically determined lower circulating LDL-C and PCSK9 concentrations may have an incremental effect in increasing T2DM incidence, but any perceived harm is outweighed by the reduced risk of atherosclerotic cardiovascular disease achieved through lower lifetime exposure to LDL-C. PCSK9 monoclonal antibodies are effective and safe in patients with T2DM and those at high risk of developing it. The number-needed-to-treat to prevent one atherosclerotic cardiovascular disease event in the FOURIER (Further Cardiovascular Outcomes Research with PCSK9 Inhibition in Subjects with Elevated Risk) study in the subgroup with diabetes is significantly lower than for those without. Therefore, T2DM or being at high risk to develop it should not be a reason to avoid these agents. The safety of PCSK9 inhibition in relation to glucose homeostasis may depend on the method of inhibition and whether it occurs in circulation or the cells. Data from experimental studies and randomized controlled trials suggest no detrimental effect of PCSK9 monoclonal antibodies on glucose homeostasis. More data and large randomized controlled studies are needed to assess the impact of other methods of PCSK9 inhibition on glucose homeostasis. Implications PCSK9monoclonal antibodies markedly reduce LDL-C and consistently reduce cardiovascular mortality in patients with and without diabetes. Current evidence does not suggest an adverse effect of PCSK9 monoclonal antibodies on glycemic parameters.