RARE DISEASE
Familial chylomicronemia syndrome
Familial chylomicronemia syndrome
Familial chylomicronemia syndrome
Drug discovery
10
drugs
With orphan designations
Overview
Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder characterized by severe hypertriglyceridemia (>10 mmol/L or >885 mg/dL) due to impaired chylomicron clearance. Caused primarily by bi-allelic loss-of-function variants in LPL (60-80% of cases) or genes regulating lipoprotein lipase activity (APOA5, APOC2, GPIHBP1, LMF1), FCS manifests with recurrent pancreatitis, abdominal pain, eruptive xanthomas, and lipemia retinalis [1][3][7]. Management centers on lifelong strict fat restriction (<20 g/day), though standard lipid-lowering therapies are largely ineffective [1][11]. Emerging RNA-targeted therapies (e.g., ApoC-III inhibitors) show promise in reducing triglycerides and pancreatitis risk [8][13].
Population
Burden
Clinical: Median 34 lifetime pancreatitis episodes; 40% require annual hospitalization [4][9][16]
Psychosocial: 58–82% report impaired mental health, employment limitations (94%), and restricted social functioning [4][14]
Economic: Mean 6.5-day hospital stays per pancreatitis episode; frequent specialist consultations and dietary management costs [4][9][14]
Therapies
Diet: First-line very low-fat diet (<10% of calories from fat) [1][3][16]
Pharmacotherapy: Volanesorsen (EU-approved ApoC-III inhibitor), olezarsen (FDA-approved RNA-targeted therapy), and investigational plozasiran (siRNA) [8][11][13]
Adjuncts: Medium-chain triglyceride (MCT) supplementation; avoidance of alcohol, refined carbohydrates, and estrogen [1][6]
Categories: rare endocrine diseases, rare genetic diseases, rare inborn errors of metabolism
Research Papers
272 drug discovery papers about Familial chylomicronemia syndrome, with 5 first-in-class and 6 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
272 drug discovery papers about Familial chylomicronemia syndrome, with 5 first-in-class and 6 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
2026-08-05 | Monogenic Familial Chylomicronemia Syndrome in Children: Clinical Divergences and Management Paradigms
Monogenic familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder caused by disrupted intravascular lipoprotein lipase (LPL) pathways. Phenotypic variation often leads to diagnostic delays. We contrast two unique pediatric presentations of FCS, highlighting distinct pathophysiology. Case 1 describes a 21-month-old girl with eruptive xanthomas, which was initially misdiagnosed as an infectious rash, later revealed to be secondary to severe hypertriglyceridemia of 100.6 mmol/L (reference range < 0.8 mmol/L). Molecular testing confirmed a genetic mutation in the GPIHBP1 gene. Case 2 describes a 2-day-old neonate with incidental finding of lipemia during jaundice evaluation, subsequently revealing a fasting triglyceride level of 8.5 mmol/L. Genetic analysis identified compound heterozygous mutations in the LPL gene. Case 1 required intensive insulin therapy, strict dietary fat restriction and adjunctive gemfibrozil. Case 2 was managed via dietary restriction and medium-chain triglyceride formula supplementation. This two-case series illustrates the diagnostic challenges of FCS in pediatric practice and the contribution of molecular confirmation to establishing the underlying aetiology and informing counselling and long-term management.
2026-07-31 | Olezarsen for hypertriglyceridemia and familial chylomicronemia syndrome: A Next-generation APOC3-targeted RNA therapy
Abstract: Olezarsen is a next-generation N acetylgalactosamine-conjugated antisense oligonucleotide (ASO) designed to selectively suppress the synthesis of apolipoprotein C-III (ApoC-III), hence reducing triglyceride (TG)-rich lipoproteins and reducing the metabolic burden of familial chylomicronemia syndrome (FCS) and severe hypertriglyceridemia (HTG). Olezarsen achieves highly efficient ApoC-III inhibition and substantial, sustained TG lowering, simultaneously minimizing systemic exposure and related adverse eventsas observed with earlier ASO therapies. Evidence accumulated from Phase 2 and pivotal Phase 3 clinical trials, namely ESSENCE–TIMI 73b, CORE–TIMI 72a/72b, and BALANCE which established consistent ~ 50%–70% reductions in plasma TGs and 60%–80% decline in ApoC-III levels among patients with severe HTG. These lipid level improvements extend to remnant cholesterol and nonhigh-density lipoprotein cholesterol, and importantly, resulted in meaningful reductions in acute pancreatitis risk in population groups who are predisposed to recurrent episodes. Compared with conventional therapy, Olezarsen exhibits enhanced hepatoselectivity and a distinctly favorable platelet safety profile, allowing its suitability for long-term management. The once-monthly subcutaneous dosing regimen further enhances adherence potential and real-world feasibility experience. With the United States Food and Drug Administration approval granted in 2024 for the treatment of FCS, Olezarsen stands as a major evolution in precision lipid therapeutics. Regulatory review is ongoing globally for broader HTG indications. Although cardiovascular outcome data and extended postmarketing surveillance results are still awaited, present clinical evidence establishes Olezarsen as a transformative therapy for patients with FCS, severe HTG, and treatment-refractory TG elevation, efficiently addressing an unmet clinical need in reducing both metabolic risk and pancreatitis-related morbidity.
2026-07-06 | Olezarsen and Plozasiran: Novel apoC-III targeting medications for the treatment of hypertriglyceridemia.
Hypertriglyceridemia is a prevalent lipid disorder associated with residual atherosclerotic cardiovascular disease (ASCVD) risk and increased risk of acute pancreatitis at triglyceride (TG) levels above 1000 mg/dL. Causes of hypertriglyceridemia are multifactorial and may be a result of secondary causes (Western diet, alcohol, medications, uncontrolled diseases/disorders), genetic disorders, or a combination of both. Two novel medications (olezarsen, plozasiran), which inhibit hepatic production of apoC-III mRNA and increase TG clearance, have recently been approved to reduce TG levels in adults with familial chylomicronemia syndrome (FCS). Both olezarsen and plozasiran have been evaluated in randomized, placebo-controlled, clinical trials in patients with varying degrees of hypertriglyceridemia. In this review, we report the lipid-lowering effects and safety of both olezarsen and plozasiran from clinical trials in patients with hypertriglyceridemia. Based on available data, both agents are associated with significant TG-lowering effects via reductions in apoC-III, as well as favorable effects on other lipid parameters. Overall, both agents appear generally well tolerated, although monitoring of liver enzymes and glycemic control is warranted for both agents, and additional monitoring of platelet counts for olezarsen. Future clinical trials are needed to assess whether the TG-lowering effects of each agent are associated with reduced risk of pancreatitis and ASCVD events.
2026-06-19 | Comparative efficacy and safety of olezarsen versus volanesorsen for familial chylomicronemia syndrome: a matching-adjusted indirect comparison.
Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by severe hypertriglyceridemia causing recurrent acute pancreatitis (AP). Since FCS is a genetic deficiency in functional lipoprotein lipase, conventional triglyceride-lowering therapies are ineffective in this metabolic disorder. Apolipoprotein C-III (apoC-III) inhibitors, including volanesorsen and olezarsen, have emerged as targeted treatments for FCS. Aim: To compare the efficacy and safety of olezarsen 80 mg every four weeks (Q4W) versus volanesorsen 300 mg weekly (QW) in patients with FCS using an anchored matching-adjusted indirect comparison. Materials & methods: Individual patient data from the Balance trial of olezarsen (n = 45) were weighted to match baseline characteristics reported in the APPROACH trial of volanesorsen (n = 66). Outcomes included percent change in fasting triglycerides (TG) and apoC-III at 26 and 52 weeks, and risks of AP events and adverse events at 52 weeks. Results: At 52 weeks, mean differences in fasting TG and apoC-III were -27.4% (95% CI: -69.4, 14.5) and -21.3% (95% CI: -61.9, 19.3). Relative risks of AP, treatment-emergent adverse events, and serious adverse events were 0.23 (95% CI: 0.01, 5.02), 0.87 (95% CI: 0.66, 1.13) and 0.50 (95% CI: 0.08, 3.26) at week 52. The rate ratio for AP events per patient-year was 0.06 (95% CI: 0.003, 1.41). No comparisons were statistically significant. Conclusion: In this matching-adjusted indirect comparison, no statistically significant differences in outcomes were observed between olezarsen and volanesorsen in patients with FCS. These findings provide important comparative context in a setting where head-to-head evidence is unavailable.
2026-06-18 | A Case of Familial Chylomicronemia Syndrome Caused by a Novel Homozygous GPIHBP1 Mutation Successfully Treated with the Selective PPARα Modulator Pemafibrate.
Familial chylomicronemia syndrome (FCS) is a rare disorder characterized by the accumulation of chylomicrons in the circulation due to genetic defects or autoantibodies affecting lipoprotein lipase (LPL), the key enzyme responsible for the metabolism of chylomicrons and very-low-density lipoproteins (VLDL), or its associated proteins, including apolipoprotein (apo) C-II, apoA-V, glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), and lipase maturation factor 1 (LMF1). This condition is associated with markedly elevated serum triglyceride (TG) levels and, in severe cases, recurrent episodes of pancreatitis and eruptive xanthomas. Among these etiologies, genetic deficiency of GPIHBP1 is exceedingly rare. We aimed to clarify the clinical and genetic basis and treatment strategies of a patient with GPIHBP1 deficiency. A 47-year-old woman with a childhood diagnosis of FCS presented with severe epigastric pain and was admitted to Rinku General Medical Center for emergency management of acute pancreatitis secondary to severe chylomicronemia. She had a history of severe hypertriglyceridemia complicated by pancreatitis during her first pregnancy and extreme hypertriglyceridemia exceeding 6,000 mg/dL during her second pregnancy without the development of pancreatitis. DNA sequence analysis was performed as a clinical diagnostic test and outsourced to KUBIX Inc. (Hakusan, Ishikawa, Japan). Laboratory evaluation revealed marked hypertriglyceridemia (1,262 mg/dL) with a type V hyperlipoproteinemia pattern. Serum preheparin LPL mass was markedly reduced, and circulating GPIHBP1 was undetectable. Genetic analysis identified a novel homozygous frameshift mutation in the GPIHBP1 gene (NM_178172.4:c.20del [p.Val7AlafsTer73]), which has not been previously reported in public databases. No pathogenic variants were detected in other LPL-related genes. Acute pancreatitis improved rapidly with fasting and intravenous fluid therapy. Strict dietary fat restriction, followed by the addition of the selective PPARα modulator pemafibrate, successfully maintained TG levels below 500 mg/dL during follow-up. We report an extremely rare case of FCS caused by a novel homozygous mutation in the GPIHBP1 gene, in which pregnancy served as a major trigger for severe hypertriglyceridemia. Early diagnosis and strict lipid control are essential to prevent recurrent pancreatitis in patients with GPIHBP1 deficiency.
2026-08-05 | Monogenic Familial Chylomicronemia Syndrome in Children: Clinical Divergences and Management Paradigms
Monogenic familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder caused by disrupted intravascular lipoprotein lipase (LPL) pathways. Phenotypic variation often leads to diagnostic delays. We contrast two unique pediatric presentations of FCS, highlighting distinct pathophysiology. Case 1 describes a 21-month-old girl with eruptive xanthomas, which was initially misdiagnosed as an infectious rash, later revealed to be secondary to severe hypertriglyceridemia of 100.6 mmol/L (reference range < 0.8 mmol/L). Molecular testing confirmed a genetic mutation in the GPIHBP1 gene. Case 2 describes a 2-day-old neonate with incidental finding of lipemia during jaundice evaluation, subsequently revealing a fasting triglyceride level of 8.5 mmol/L. Genetic analysis identified compound heterozygous mutations in the LPL gene. Case 1 required intensive insulin therapy, strict dietary fat restriction and adjunctive gemfibrozil. Case 2 was managed via dietary restriction and medium-chain triglyceride formula supplementation. This two-case series illustrates the diagnostic challenges of FCS in pediatric practice and the contribution of molecular confirmation to establishing the underlying aetiology and informing counselling and long-term management.
2026-07-31 | Olezarsen for hypertriglyceridemia and familial chylomicronemia syndrome: A Next-generation APOC3-targeted RNA therapy
Abstract: Olezarsen is a next-generation N acetylgalactosamine-conjugated antisense oligonucleotide (ASO) designed to selectively suppress the synthesis of apolipoprotein C-III (ApoC-III), hence reducing triglyceride (TG)-rich lipoproteins and reducing the metabolic burden of familial chylomicronemia syndrome (FCS) and severe hypertriglyceridemia (HTG). Olezarsen achieves highly efficient ApoC-III inhibition and substantial, sustained TG lowering, simultaneously minimizing systemic exposure and related adverse eventsas observed with earlier ASO therapies. Evidence accumulated from Phase 2 and pivotal Phase 3 clinical trials, namely ESSENCE–TIMI 73b, CORE–TIMI 72a/72b, and BALANCE which established consistent ~ 50%–70% reductions in plasma TGs and 60%–80% decline in ApoC-III levels among patients with severe HTG. These lipid level improvements extend to remnant cholesterol and nonhigh-density lipoprotein cholesterol, and importantly, resulted in meaningful reductions in acute pancreatitis risk in population groups who are predisposed to recurrent episodes. Compared with conventional therapy, Olezarsen exhibits enhanced hepatoselectivity and a distinctly favorable platelet safety profile, allowing its suitability for long-term management. The once-monthly subcutaneous dosing regimen further enhances adherence potential and real-world feasibility experience. With the United States Food and Drug Administration approval granted in 2024 for the treatment of FCS, Olezarsen stands as a major evolution in precision lipid therapeutics. Regulatory review is ongoing globally for broader HTG indications. Although cardiovascular outcome data and extended postmarketing surveillance results are still awaited, present clinical evidence establishes Olezarsen as a transformative therapy for patients with FCS, severe HTG, and treatment-refractory TG elevation, efficiently addressing an unmet clinical need in reducing both metabolic risk and pancreatitis-related morbidity.
2026-07-06 | Olezarsen and Plozasiran: Novel apoC-III targeting medications for the treatment of hypertriglyceridemia.
Hypertriglyceridemia is a prevalent lipid disorder associated with residual atherosclerotic cardiovascular disease (ASCVD) risk and increased risk of acute pancreatitis at triglyceride (TG) levels above 1000 mg/dL. Causes of hypertriglyceridemia are multifactorial and may be a result of secondary causes (Western diet, alcohol, medications, uncontrolled diseases/disorders), genetic disorders, or a combination of both. Two novel medications (olezarsen, plozasiran), which inhibit hepatic production of apoC-III mRNA and increase TG clearance, have recently been approved to reduce TG levels in adults with familial chylomicronemia syndrome (FCS). Both olezarsen and plozasiran have been evaluated in randomized, placebo-controlled, clinical trials in patients with varying degrees of hypertriglyceridemia. In this review, we report the lipid-lowering effects and safety of both olezarsen and plozasiran from clinical trials in patients with hypertriglyceridemia. Based on available data, both agents are associated with significant TG-lowering effects via reductions in apoC-III, as well as favorable effects on other lipid parameters. Overall, both agents appear generally well tolerated, although monitoring of liver enzymes and glycemic control is warranted for both agents, and additional monitoring of platelet counts for olezarsen. Future clinical trials are needed to assess whether the TG-lowering effects of each agent are associated with reduced risk of pancreatitis and ASCVD events.
2026-06-19 | Comparative efficacy and safety of olezarsen versus volanesorsen for familial chylomicronemia syndrome: a matching-adjusted indirect comparison.
Background: Familial chylomicronemia syndrome (FCS) is a rare genetic disorder characterized by severe hypertriglyceridemia causing recurrent acute pancreatitis (AP). Since FCS is a genetic deficiency in functional lipoprotein lipase, conventional triglyceride-lowering therapies are ineffective in this metabolic disorder. Apolipoprotein C-III (apoC-III) inhibitors, including volanesorsen and olezarsen, have emerged as targeted treatments for FCS. Aim: To compare the efficacy and safety of olezarsen 80 mg every four weeks (Q4W) versus volanesorsen 300 mg weekly (QW) in patients with FCS using an anchored matching-adjusted indirect comparison. Materials & methods: Individual patient data from the Balance trial of olezarsen (n = 45) were weighted to match baseline characteristics reported in the APPROACH trial of volanesorsen (n = 66). Outcomes included percent change in fasting triglycerides (TG) and apoC-III at 26 and 52 weeks, and risks of AP events and adverse events at 52 weeks. Results: At 52 weeks, mean differences in fasting TG and apoC-III were -27.4% (95% CI: -69.4, 14.5) and -21.3% (95% CI: -61.9, 19.3). Relative risks of AP, treatment-emergent adverse events, and serious adverse events were 0.23 (95% CI: 0.01, 5.02), 0.87 (95% CI: 0.66, 1.13) and 0.50 (95% CI: 0.08, 3.26) at week 52. The rate ratio for AP events per patient-year was 0.06 (95% CI: 0.003, 1.41). No comparisons were statistically significant. Conclusion: In this matching-adjusted indirect comparison, no statistically significant differences in outcomes were observed between olezarsen and volanesorsen in patients with FCS. These findings provide important comparative context in a setting where head-to-head evidence is unavailable.
2026-06-18 | A Case of Familial Chylomicronemia Syndrome Caused by a Novel Homozygous GPIHBP1 Mutation Successfully Treated with the Selective PPARα Modulator Pemafibrate.
Familial chylomicronemia syndrome (FCS) is a rare disorder characterized by the accumulation of chylomicrons in the circulation due to genetic defects or autoantibodies affecting lipoprotein lipase (LPL), the key enzyme responsible for the metabolism of chylomicrons and very-low-density lipoproteins (VLDL), or its associated proteins, including apolipoprotein (apo) C-II, apoA-V, glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), and lipase maturation factor 1 (LMF1). This condition is associated with markedly elevated serum triglyceride (TG) levels and, in severe cases, recurrent episodes of pancreatitis and eruptive xanthomas. Among these etiologies, genetic deficiency of GPIHBP1 is exceedingly rare. We aimed to clarify the clinical and genetic basis and treatment strategies of a patient with GPIHBP1 deficiency. A 47-year-old woman with a childhood diagnosis of FCS presented with severe epigastric pain and was admitted to Rinku General Medical Center for emergency management of acute pancreatitis secondary to severe chylomicronemia. She had a history of severe hypertriglyceridemia complicated by pancreatitis during her first pregnancy and extreme hypertriglyceridemia exceeding 6,000 mg/dL during her second pregnancy without the development of pancreatitis. DNA sequence analysis was performed as a clinical diagnostic test and outsourced to KUBIX Inc. (Hakusan, Ishikawa, Japan). Laboratory evaluation revealed marked hypertriglyceridemia (1,262 mg/dL) with a type V hyperlipoproteinemia pattern. Serum preheparin LPL mass was markedly reduced, and circulating GPIHBP1 was undetectable. Genetic analysis identified a novel homozygous frameshift mutation in the GPIHBP1 gene (NM_178172.4:c.20del [p.Val7AlafsTer73]), which has not been previously reported in public databases. No pathogenic variants were detected in other LPL-related genes. Acute pancreatitis improved rapidly with fasting and intravenous fluid therapy. Strict dietary fat restriction, followed by the addition of the selective PPARα modulator pemafibrate, successfully maintained TG levels below 500 mg/dL during follow-up. We report an extremely rare case of FCS caused by a novel homozygous mutation in the GPIHBP1 gene, in which pregnancy served as a major trigger for severe hypertriglyceridemia. Early diagnosis and strict lipid control are essential to prevent recurrent pancreatitis in patients with GPIHBP1 deficiency.
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Drug Discovery Landscape
10 orphan drug designations for Familial chylomicronemia syndrome, including 5 approved therapies.
10 orphan drug designations for Familial chylomicronemia syndrome, including 5 approved therapies.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
Olezarsen sodium [Tryngolza] | oligonucleotides | EMA | 2024-08-21 | 2025-09-18 | Swedish Orphan Biovitrum AB (publ) |
olezarsen [Tryngolza] | RNAs | FDA | 2024-02-14 | 2024-12-19 | Ionis Pharmaceuticals |
Synthetic double-stranded siRNA oligonucleotide directed against apolipoprotein C-III mRNA and covalently linked to a ligand containing three N-acetylgalactosamine residues [Redemplo] | RNAs | EMA | 2021-07-19 | 2026-06-22 | Arrowhead Pharmaceuticals Ireland Limited |
plozasiran [Redemplo] | RNAs | FDA | 2019-06-20 | 2025-11-18 | Arrowhead Pharmaceuticals, Inc. |
volanesorsen sodium, apolipotrotein C-III antisense oligonucleotide | oligonucleotides | FDA | 2015-06-23 | — | Akcea Therapeutics, Inc. |
Phosphorothioate oligonucleotide targeted to apolipoprotein C-III [Waylivra] | oligonucleotides | EMA | 2014-02-19 | 2019-05-08 | Akcea Therapeutics Ireland Limited |
Pradigastat | small molecules | EMA | 2012-09-14 | — | Novartis Europharm Limited |
selective deacylglycerol acyltransferase 1 inhibitor | small molecules | FDA | 2011-03-28 | — | Novartis Pharmaceuticals Corporation |
lomitapide | small molecules | FDA | 2011-03-03 | — | Chiesi Farmaceutici S.p.A. |
Lomitapide | small molecules | EMA | 2010-12-17 | — | Chiesi Farmaceutici S.p.A. |
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