Management of severe hypertriglyceridemia due to lipoprotein lipase deficiency in children

Plozasiran (ARO-APOC3) for Severe Hypertriglyceridemia: The SHASTA-2 Randomized Clinical Trial

Importance

Severe hypertriglyceridemia (sHTG) confers increased risk of atherosclerotic cardiovascular disease (ASCVD), nonalcoholic steatohepatitis, and acute pancreatitis. Despite available treatments, persistent ASCVD and acute pancreatitis-associated morbidity from sHTG remains.

Objective

To determine the tolerability, efficacy, and dose of plozasiran, an APOC3-targeted small interfering-RNA (siRNA) drug, for lowering triglyceride and apolipoprotein C3 (APOC3, regulator of triglyceride metabolism) levels and evaluate its effects on other lipid parameters in patients with sHTG.

Design, Setting, and Participants

The Study to Evaluate ARO-APOC3 in Adults With Severe Hypertriglyceridemia (SHASTA-2) was a placebo-controlled, double-blind, dose-ranging, phase 2b randomized clinical trial enrolling adults with sHTG at 74 centers across the US, Europe, New Zealand, Australia, and Canada from May 31, 2021, to August 31, 2023. Eligible patients had fasting triglyceride levels in the range of 500 to 4000 mg/dL (to convert to millimoles per liter, multiply by 0.0113) while receiving stable lipid-lowering treatment.

Interventions

Participants received 2 subcutaneous doses of plozasiran (10, 25, or 50 mg) or matched placebo on day 1 and at week 12 and were followed up through week 48.

Main Outcomes and Measures

The primary end point evaluated the placebo-subtracted difference in means of percentage triglyceride change at week 24. Mixed-model repeated measures were used for statistical modeling.

Results

Of 229 patients, 226 (mean [SD] age, 55 [11] years; 176 male [78%]) were included in the primary analysis. Baseline mean (SD) triglyceride level was 897 (625) mg/dL and plasma APOC3 level was 32 (16) mg/dL. Plozasiran induced significant dose-dependent placebo-adjusted least squares (LS)-mean reductions in triglyceride levels (primary end point) of -57% (95% CI, -71.9% to -42.1%; P < .001), driven by placebo-adjusted reductions in APOC3 of -77% (95% CI, -89.1% to -65.8%; P < .001) at week 24 with the highest dose. Among plozasiran-treated patients, 144 of 159 (90.6%) achieved a triglyceride level of less than 500 mg/dL. Plozasiran was associated with dose-dependent increases in low-density lipoprotein cholesterol (LDL-C) level, which was significant in patients receiving the highest dose (placebo-adjusted LS-mean increase 60% (95% CI, 31%-89%; P < .001). However, apolipoprotein B (ApoB) levels did not increase, and non-high-density lipoprotein cholesterol (HDL-C) levels decreased significantly at all doses, with a placebo-adjusted change of -20% at the highest dose. There were also significant durable reductions in remnant cholesterol and ApoB48 as well as increases in HDL-C level through week 48. Adverse event rates were similar in plozasiran-treated patients vs placebo. Serious adverse events were mild to moderate, not considered treatment related, and none led to discontinuation or death.

Conclusions and Relevance

In this randomized clinical trial of patients with sHTG, plozasiran decreased triglyceride levels, which fell below the 500 mg/dL threshold of acute pancreatitis risk in most participants. Other triglyceride-related lipoprotein parameters improved. An increase in LDL-C level was observed but with no change in ApoB level and a decrease in non-HDL-C level. The safety profile was generally favorable at all doses. Additional studies will be required to determine whether plozasiran favorably modulates the risk of sHTG-associated complications.

Trial Registration

ClinicalTrials.gov Identifier: NCT04720534.

[A case of neonatal-onset type I hyperlipoproteinemia with bloody ascites]

This report presents a case of a male infant, aged 32 days, who was admitted to the hospital due to 2 days of bloody stools and 1 day of fever. Upon admission, venous blood samples were collected, which appeared pink. Blood biochemistry tests revealed elevated levels of triglycerides and total cholesterol. The familial whole genome sequencing revealed a compound heterozygous variation in the LPL gene, with one variation inherited from the father and the other from the mother. The patient was diagnosed with lipoprotein lipase deficiency-related hyperlipoproteinemia. Acute symptoms including bloody stools, fever, and bloody ascites led to the consideration of acute pancreatitis, and the treatment involved fasting, plasma exchange, and whole blood exchange. Following the definitive diagnosis based on the genetic results, the patient was given a low-fat diet and received treatment with fat-soluble vitamins and trace elements, as well as adjustments to the feeding plan. After a 4-week hospitalization, the patient's condition improved and he was discharged. Follow-up showed a decrease in triglycerides and total cholesterol levels. At the age of 1 year, the patient's growth and psychomotor development were normal. This article emphasizes the multidisciplinary diagnosis and treatment of familial hyperlipoproteinemia presenting with symptoms suggestive of acute pancreatitis, including bloody ascites, in the neonatal period.

Diagnosis of Acute Pancreatitis Secondary to Hypertriglyceridemia in a Pediatric Patient in the Emergency Department

The incidence of acute pancreatitis in pediatric patients has increased in the last decade. We present the case of an eight-year-old boy who presented to the emergency department from another healthcare facility for the evaluation of appendicitis and was found to have acute pancreatitis secondary to hypertriglyceridemia. Clinical suspicion of pancreatitis should remain high in the pediatric patient population with nausea, emesis, and abdominal pain considering that pancreatitis' often atypical and non-specific presentation may lead to delayed diagnosis.

Comparison of plasmapheresis with medical apheresis in terms of efficacy and cost in the acute treatment of hypertriglyceridemia in children with lipoprotein lipase deficiency

OBJECTIVES

We aimed to compare plasmapheresis and medical apheresis as lipid-lowering therapies in children with familial lipoprotein lipase (LPL) deficiency.

METHODS

The data of 13 patients who were followed up after a diagnosis of LPL deficiency were retrospectively analyzed. Plasma triglyceride, cholesterol, amylase, and lipase values and complications were recorded before and after each patient underwent plasmapheresis or medical apheresis.

RESULTS

The mean follow-up period of the patients was 99.64 ± 52.92 months in the medical apheresis group and 118 ± 16.97 months in the plasmapheresis group. While the mean triglyceride level before plasmapheresis was 1,875.38 ± 547.46 mg/dL, it was 617 ± 228.28 mg/dL after plasmapheresis. While the mean triglyceride level before medical apheresis was 1,756.86 ± 749.27 mg/dL, it was found to be 623.03 ± 51.36 mg/dL after medical apheresis. Triglyceride levels were decreased by 59.62% with medical apheresis and 65.57% with plasmapheresis. The cost of treatment for medical apheresis was found to be lower compared to plasmapheresis 296.93 ± 29.94 Turkish lira (USD 43.34 ± 4.01) vs. 3,845.42 ± 156.17 Turkish lira (USD 561.37 ± 20.93; p<0.001).

CONCLUSIONS

Although there is no standardized strategy for the acute treatment of hypertriglyceridemia due to LPL deficiency, medical apheresis is a safe and effective treatment with a low risk of side effects. Unlike plasmapheresis, medical apheresis can be performed in any center, which is another important advantage of the procedure.

Management strategy and novel ophthalmological findings in neonatal severe hypertriglyceridemia: a case report and literature review

Background

Neonatal severe hypertriglyceridemia is rarely reported in the literature and there is no consensus for hypertriglyceridemia management at this age group.

Methods

The index case is a 4-week-old male infant with severe hypertriglyceridemia accidentally discovered during a circumcision surgery. His clinical and genetic characteristics and his successful management strategy are described. Furthermore, a detailed ophthalmological examination of the proband was conducted at 3 and 6 months of age using Fourier-domain-optical coherence tomography.

Results

Triglycerides level at presentation was extremely high 33,727 mg/dL (380.8 mmol/L). Two sessions of exchange blood transfusion on two consecutive days successfully reduced triglycerides to 382 mg/dL (4.3 mmol/L) with no adverse effects. The infant was discharged 3 days later. At discharge, the mother was advised to continue breastfeeding together with a medium-chain triglycerides formula. Satisfactory growth parameters and lipid profile values were obtained for a follow-up duration of 5 months with no reported attacks of acute pancreatitis. Lipoprotein lipase deficiency was confirmed by the detection of the LPL homozygous pathogenic variant c.805G > A; p.(Glu269Lys). Early corneal and macular lesions were detected and persisted on follow-up despite relatively good lipemic control.

Conclusion

This case highlights the importance of the early discovery of severe hypertriglyceridemia during the neonatal period, which is needed for prompt management and prevention of severe complications. Rationalized breastfeeding can be tolerated within the diet plan of the disease with satisfactory outcomes. To our knowledge, it is the first study reporting early corneal and macular affection by severe hypertriglyceridemia in a neonate. Prolonged follow-up is needed to determine the extent of ophthalmological lesions.