Symptoms and impacts of familial chylomicronemia syndrome: a qualitative study of the patient experience

BACKGROUND

Familial chylomicronemia syndrome (FCS) is a rare, hereditary, metabolic disorder. FCS causes high levels of triglycerides in the blood, which can lead to abdominal pain, xanthomas, and acute pancreatitis (AP). Volanesorsen, along with adherence to a very low-fat diet is used to reduce triglyceride levels in individuals with FCS. We aimed to understand the symptoms of FCS and their impact on health-related quality of life (HRQoL).

METHODS

Interviews were conducted with individuals with genetically confirmed FCS in the UK and Spain, some of whom had been treated with volanesorsen. Interview guides were developed with input from a patient advocacy group to explore the symptoms, impacts and management of FCS. Interviews were conducted by telephone and were recorded and transcribed. Data were analyzed using thematic analysis and saturation was recorded.

RESULTS

Seventeen interviews were conducted with individuals with FCS (aged 27-68 years), thirteen of whom were currently/previously treated with volanesorsen. Episodes of AP were the most impactful reported symptom, resulting in severe abdominal pain, nausea, vomiting, fever, bloating and appetite loss. Other symptoms and functional issues included abdominal pain, gastrointestinal symptoms, impaired cognitive function and fatigue. These had an impact on work, social activities, relationships and psychological wellbeing. These symptoms and impacts were illustrated in a conceptual model, including management strategies. The challenges of managing a low-fat diet and experience with volanesorsen were discussed.

CONCLUSION

Individuals with FCS experience a range of interrelated symptoms and functional limitations which impact their broader HRQoL. Treatments which alleviate symptoms and reduce the incidence of AP episodes have the potential to improve the HRQoL of these individuals.

Hypertriglyceridemia: rationale, design and implementation of the Australian Hypertriglyceridemia Registry

PURPOSE OF REVIEW

Hypertriglyceridemia (HTG) is a risk factor for atherosclerotic cardiovascular disease (ASCVD), aortic stenosis, hepatic steatosis and pancreatitis. We briefly review the aetiology and treatment of HTG and familial chylomicronemia syndrome (FCS), as well as the implementation of a clinical quality registry for improving care, the Australian Hypertriglyceridemia (AUSTRIG) Registry.

RECENT FINDINGS

There is a need to improve the detection of individuals with severe HTG and FCS, who could benefit from more intense and novel treatments to prevent end-organ damage. Patient registries provide valuable data for advancing care of individuals with severe HTG at high risk of acute pancreatitis, steatohepatitis and ASCVD. However, there is a paucity of registries of such patients. We outline the design and implementation of the AUSTRIG Registry.

SUMMARY

Clinical registries can be employed in many ways for improving outcomes for patients with HTG, through the collation and analysis of data for enabling health service planning, clinical trials and audits, and for better informing and empowering registrants.

Triglyceride metabolism and classification of hypertriglyceridemias

Triglycerides (TG) are the most important molecules for the energy reserve of our body. After their hepatic or intestinal synthesis from fatty acids, they are carried by chylomicrons (QM (intestinal origin) or VLDL (hepatic origin) in plasma. Their catabolism is determined by the action of the lipoprotein lipase protein complex (LPL) and the hepatic receptors (RLDL and LRP-1) are responsible for their clearance are. Changes in the production or catabolism leads to hypertriglyceridaemia (HTG). The HTG are classified according to severity as, mild-moderate (150-885mg/dl), severe (>885mg/dl), or very severe (>1770mg/dl). They can be primary and secondary depending on origin. In the main primary form is highlighted Familial Chylomicronaemia Syndrome (CFS), a very severe form due to mutations in the LPL gene or associated proteins. Most HTG are due to a combination of genetic and environmental predisposing factors.

Effectiveness and safety of lomitapide in a patient with familial chylomicronemia syndrome

BACKGROUND

Familial chylomicronemia syndrome (FCS) is characterized by severe fasting hypertriglyceridemia, abdominal pain, and recurrent acute pancreatitis. Available triglyceride-lowering drugs are insufficient to avoid pancreatitis. Therefore, there is a significant unmet medical need for effective triglyceride-lowering drugs for patients with FCS.

CASE REPORT

We report the second case of a patient with FCS and recurrent pancreatitis treated with lomitapide. Lomitapide treatment resulted in a reduction of fasting TG levels from 2897 mg/dL (32.71 mmol/L) to an average of 954 mg/dL (10.77 mmol/L) on the 30 mg lomitapide equating to a 67% reduction from baseline. After 26 months of lomitapide treatment, histological activity score for hepatic fibrosis was stable although liver biopsy showed a marked increase of liver steatosis and mild perivenular and perisinusoidal fibrosis.

CONCLUSIONS

Lomitapide is effective in reducing triglycerides in FCS and preventing the recurrence of acute pancreatitis. A longer follow-up is necessary to evaluate long-term risk of progression toward severe stages of liver fibrosis. A prospective clinical trial may identify which subgroup of FCS patients would benefit from lomitapide treatment in the absence of significant liver adverse effects.

An Infant with Milky Serum and a Rare Mutation

A 40-day-infant having milky serum, eruptive xanthomas, hepatosplenomegaly, lipemia retinalis, high cholesterol and triglyceride, was found to have lipoprotein lipase (LPL) deficiency on genetic workup. Triglyceride decreased with dietary fat restriction, medium chain triglyceride and fibrates. LPL deficiency in early infancy can be treated with pharmacological and dietary interventions.

[Familial chylomicronemia]

Familial chylomicronemia is a disease in which a genetic mutation affects the ability of the organism to metabolize triglycerides bound to lipoproteins, causing extremely high plasma triglycerides and associated consequences. The most frequent complication is acute pancreatitis, which may lead to multiorganic failure or pancreatic insufficiency. Familial chylomicronemia also exerts a profound negative impact on quality of life, social relationships and professional development. The gene most frequently affected is lipoprotein lipase-1 gene (LPL), the enzyme in charge of hydrolyzing circulating triglycerides for tissue uptake. Mutations in other genes regulating maturation, transport or polymerization (eg. APOC2, APOAV, LMF-1, GPIHBP-1) of lipoprotein lipase-1, may also be involved. However, in about 30% of patients the causal variant is not identified. Familial chylomicronemia should be suspected in patients with severe hypertriglyceridemia with poor response to conventional treatment, or accompanied by eruptive xanthomas, lipemia retinalis or abdominal pain. The availability of risk scores and genetic tests should facilitate its opportune detection and management. Nutritional therapy is based on a very-low-fat diet with adequate supply of lipid-soluble vitamins and essential fatty acids, plus avoidance of alcohol consumption. Current pharmacological treatment may include fibrates and omega-3 fatty acids but prioritizes biotechnological agents targeting the molecular disturbances of the disease. These include an antisense oligonucleotide against apoC-III (volanesorsen), a monoclonal antibody against angiopoietin-like protein-3 (evinacumab), and other agents currently in development.

STUDIES OF THE INFLUENCE OF DIET ON CLEARING-FACTOR LIPASE (CFL) AND BLOOD LIPID LEVELS OF A PATIENT WITH HYPERLIPIDEMIA

A 30-year-old man was studied who had hyperlipidemia of a hereditary nature which was at first thought to be refractory to changes in diet. It was subsequently shown that the lipemia was adequately controlled by diet. The patient had no defect in his ability to produce clearing-factor lipase (CFL) following heparin injection, his chylomicra were not refractory to CFL, and his plasma showed no more than ordinary inhibitory activity against CFL. Under dietary conditions which resulted in a high degree of lipemia, much of the CFL was rendered inactive by adsorption on the chylomicra. The results suggest that the role of CFL in patients with hyperlipidemia may be minor.