Indications for apheresis as an ultima ratio treatment of refractory hyperlipidemias

Changing from lipoprotein apheresis to evolocumab treatment lowers circulating levels of arachidonic acid and oxylipins

Background and aims

Previous studies have shown that lipoprotein apheresis can modify the plasma lipidome and pro-inflammatory and pro-thrombotic lipid mediators. This has not been examined for treatment with protein convertase subtilisin/kexin type 9 inhibitors such as evolocumab, which are increasingly used instead of lipoprotein apheresis in treatment-resistant familial hypercholesterolemia. The aim of this study was to compare the effects of evolocumab treatment and lipoprotein apheresis on the fatty acid profile and on formation of lipid mediators in blood samples.

Methods

We analyzed blood samples from 37 patients receiving either lipoprotein apheresis or evolocumab treatment as part of a previous study. Patients were stratified according to receiving lipoprotein apheresis (n = 19) and evolocumab treatment (n = 18). Serum fatty acid analysis was performed using gas chromatography flame ionization detection and plasma oxylipin analysis was done using liquid chromatography tandem mass spectrometry.

Results

Changing from lipoprotein apheresis to evolocumab treatment led to lower levels of omega-6 polyunsaturated fatty acid (n-6 PUFA) including arachidonic acid, dihomo-γ-linolenic acid and linoleic acid. Moreover, several n-6 PUFA-derived oxylipins were reduced after evolocumab treatment.

Conclusions

Given that arachidonic acid, either directly or as a precursor, is associated with the development of inflammation and atherosclerosis, evolocumab-mediated reductions of arachidonic acid and its metabolites might have an additional beneficial effect to lower cardiovascular risk.

[Lipoprotein apheresis : State of the art and case report of the longest HELP treatment worldwide]

Lipoprotein apheresis is an extracorporeal procedure for the treatment of patients with homozygous familial hypercholesterolemia, patients with severe treatment-resistant hypercholesterolemia and patients with lipoprotein(a) hypercholesterolemia, who show progressive atherosclerotic cardiovascular disease despite optimal treatment. This article reports on the historical developments of the procedures, the most frequently used methods for apheresis as well as the data situation on efficacy and tolerability. Randomized prospective studies on clinical outcomes are not available. Furthermore, the article reports on a patient with homozygous familial hypercholesterolemia and 34 years of treatment with heparin-induced extracorporeal low-density lipoprotein (LDL) precipitation (HELP) apheresis, the longest treatment of this kind worldwide. A second patient with combined heterozygous familial hypercholesterolemia and 31 years of liposorber and HELP apheresis is also described. The observational studies and the case reports demonstrate the safety and long-term tolerability of the procedure.

Lomitapide and Mipomersen-Inhibiting Microsomal Triglyceride Transfer Protein (MTP) and apoB100 Synthesis

PURPOSE OF REVIEW

The goal of this review is to evaluate the role of inhibiting the synthesis of lipoproteins when there is no or little residual LDL-receptor function as in patients with homozygous familial hypercholesterolaemia. Lomitapide is administered orally once a day while mipomersen is given by subcutaneous injection once a week. Lomitapide inhibits microsomal triglyceride transfer protein while mipomersen is an antisense oligonucleotide directed against apoB100.

RECENT FINDINGS

The pivotal registration trials for lomitapide and mipomersen were published in 2013 and 2010, respectively. More recently published data from extension trials and cohort studies provides additional information on long-term safety and efficacy. The mean LDL cholesterol reduction was 50% with lomitapide in its single-arm open-label registration trial. Mipomersen reduced LDL cholesterol by approximately 25% in its double-blind, placebo-controlled registration study. Both lomitapide and mipomersen therapy are associated with variable increases in hepatic fat content. The long-term safety of increased hepatic fat content in patients receiving these therapies is uncertain and requires further study. Both drugs may cause elevated transaminase in some patients, but no cases of severe liver injury have been reported. Lomitapide may also cause gastrointestinal discomfort and diarrhoea, especially if patients consume high-fat meals and patients are advised to follow a low-fat diet supplemented with essential fatty acids and fat-soluble vitamins. Mipomersen may cause injection-site and influenza-like reactions. The effect of lomitapide and mipomersen on cardiovascular outcomes has not been studied, but circumstantial evidence suggests that the LDL cholesterol lowering achieved with these two agents may reduce cardiovascular event rates.

Activation of Lipid Mediator Formation Due to Lipoprotein Apheresis

Lipoprotein apheresis reliably reduces low-density lipoprotein (LDL) cholesterol in patients with atherosclerotic disease and therapy-refractory hypercholesterolemia or elevated lipoprotein (a) (Lp(a)). Besides lowering lipoproteins and triglycerides, apheresis also decreases levels of essential omega-6 and omega-3 polyunsaturated fatty acids (n-6 and n-3 PUFAs) in blood plasma. In contrast, heparin-induced extracorporeal low-density lipoprotein precipitation (HELP) lipid apheresis might increase the formation of potentially pro-inflammatory and pro-thrombotic lipid mediators derived from n-6 and n-3 PUFAs. The study presented here analyzed lipid mediator profiles in the plasma of patients with hyperlipidemia treated by one of three different apheresis methods, either HELP, direct absorption (DA), or membrane filtration (MDF), in a direct pre- and post-apheresis comparison. Using gas chromatography and liquid chromatography tandem mass spectrometry (LC-MS/MS) we were able to analyze fatty acid composition and the formation of lipid mediators called oxylipins. Our data illustrate—particularly in HELP-treated patients—significant decreases of essential omega-6 and omega-3 polyunsaturated fatty acids in blood plasma but significant increases of PUFA-derived lipoxygenase-, as well as cyclooxygenase- and cytochrome P450-derived lipid mediators. Given that n-3 PUFAs in particular are presumed to be cardioprotective and n-3 PUFA-derived lipid mediators might limit inflammatory reactions, these data indicate that n-3 PUFA supplementation in the context of lipid apheresis treatment might have additional benefits through apheresis-triggered protective n-3 PUFA-derived lipid mediators.

Efficacy of lipid reduction with DALI and MONET

BACKGROUND

Lipidapheresis techniques are increasingly used to treat drug-resistant hyperlipidemia but few efficacy studies under routine application are available. In this multicenter observational study we investigated direct adsorption of lipoproteins (DALI) and lipoprotein filtration (MONET) for the short and the long-term effects on lipid-lowering effects.

METHODS

Data of 122 apheresis patients from 11 centers (DALI: n = 78, MONET: n = 44) were prospectively collected for a period of 2 years. Routine lipid measurements were evaluated (2154 DALI and 1297 MONET sessions). It was investigated whether the relative reduction of LDL-C during apheresis session achieves at least 60%. Also relative reduction of total cholesterol, HDL, triglyceride, and Lp(a) were analyzed.

RESULTS

The relative reduction of LDL-C was at least 60%: DALI: 70.62%, 95% CI = [69.34; 71.90] and MONET: 64.12%, 95% CI = [60.79; 67.46]. Also triglycerides were reduced with both systems: DALI 38.63%, 95% CI = [33.95; 43.30] vs. MONET 57.68%, 95% CI = [51.91; 63.45]. Relative reductions of total cholesterol were in the range of 50% (DALI 95% CI = [46.49; 49.65] MONET 95% CI = [48.93; 55.26]) and of Lp(a) in the range of 65% (DALI 95% CI = [61.92; 65.83] MONET 95% CI = [63.71; 70.30]. HDL reduction was: DALI 15.01%, 95% CI = [13.22; 16.79] and MONET 22.59%, 95% CI = [19.33; 25.84]. For both devices treated patient plasma/blood volume and in case of DALI the use of the larger adsorber configurations (DALI 1000 and DALI 1250) were independent positive predictors of the relative reduction of LDL-C and of Lp(a).

CONCLUSIONS

Both systems effectively improved lipid profile and reduced atherogenic lipids. The results point to the importance of the individualized application of these valuable therapies to achieve clinical targets.