Drug Update · Cardiology

FDA Approves Olezarsen for FCS: Cuts TG 43% vs Placebo

September 03, 2026

Primary efficacy (FCS Month 6)

-43% (treatment difference vs placebo; 95% CI: -74%, -11%; p=0.0084)

Trial

Trial 1 (NCT04568434)

FDA approval date

12/19/2024

FCS approved dose

80 mg subcutaneously once monthly

Clinical Perspective

Clinicians caring for lipid specialists, cardiologists, endocrinologists, and other clinicians who manage adults with familial chylomicronemia syndrome may consider TRYNGOLZA as an adjunct to diet to reduce triglycerides based on the FDA approval and Trial 1 efficacy data ^[4]^[5]. The source-confirmed data support clinically meaningful TG lowering (treatment difference -43% vs placebo at Month 6) and a numerical reduction in pancreatitis events over 12 months in Trial 1, with safety signals that include hypersensitivity, platelet reductions, injection site reactions, liver enzyme and hepatic fat changes, and glycemic increases that warrant monitoring per the label ^[5]^[1]^[2]. What role TRYNGOLZA will have relative to existing background therapies (including fibrates used by many trial participants) and long-term effects on pancreatitis prevention require further real-world and longer-term data?

Dr. Kavya Sharma, MBBS, MD (General Medicine), DM (Cardiology) · Cardiology

The U.S. Food and Drug Administration approved TRYNGOLZA (olezarsen) to reduce triglycerides (TG) in adults with familial chylomicronemia syndrome (FCS) on 12/19/2024 based on a randomized, placebo-controlled trial (Trial 1; NCT04568434) showing a treatment difference in percent change in fasting TG of -43% versus placebo at Month 6 (95% CI: -74%, -11%; p=0.0084) ^[4]^[5]. The label also includes dosing and safety information for adults with severe hypertriglyceridemia (sHTG) following supplemental labeling updates in 2026 ^[2]^[3]^[5].

Clinical Context

Olezarsen (TRYNGOLZA) is an apolipoprotein C-III (apoC-III)-directed antisense oligonucleotide (ASO) conjugated to a GalNAc ligand for hepatocyte delivery; the mechanism is to reduce apoC-III mRNA and serum apoC-III protein, leading to increased clearance of plasma triglycerides and VLDL ^[1]^[5]. The FDA described the approval for FCS as a first-in-class approval reflecting a different mechanism of action from existing therapies used in these patients ^[4]. Ionis Pharmaceuticals is the developer/packager listed in prescribing materials and DailyMed ^[1]^[2]^[3]. In Trial 1, many patients were already treated with background lipid-lowering therapies including statins, omega-3 fatty acids, and fibrates at study entry, but the trials reported placebo-controlled effects of olezarsen rather than head-to-head comparisons with other lipid-lowering agents ^[5].

Key Findings

Trial 1 (NCT04568434) in adults with genetically identified FCS and fasting TG ≥880 mg/dL showed TRYNGOLZA 80 mg every 4 weeks reduced fasting triglycerides by a treatment difference of -43% versus placebo in percent change from baseline to Month 6 (95% CI: -74%, -11%; p=0.0084) ^[5].
Clinicians should consult current prescribing information for full dosing guidance.
Median and mean TG reductions were consistent over a 12-month treatment period, and the numerical incidence of acute pancreatitis over 12 months was lower with TRYNGOLZA 80 mg (1 patient, 5%) versus placebo (7 patients, 30%); all affected patients had prior pancreatitis within 10 years before screening ^[5].
In pooled Phase 3 trials in adults with severe hypertriglyceridemia (Trials 2 and 3), TRYNGOLZA demonstrated placebo-corrected percent TG reductions at Month 6 of -63% for 50 mg and -72% for 80 mg in Trial 2, with statistically significant decreases at Month 6 and Month 12 across trials ^[5]^[2].

Safety & Tolerability

Hypersensitivity reactions, including bronchospasm, diffuse erythema, facial swelling, urticaria, chills, and myalgias, have been reported; TRYNGOLZA is contraindicated in patients with a history of serious hypersensitivity to olezarsen or excipients ^[1]^[2]^[5].
Injection site reactions were reported more frequently with TRYNGOLZA than placebo (Trial 1: 8/43 [19%] vs 2/23 [9%]; Trials 2/3 pooled: TRYNGOLZA 50 mg 12%, 80 mg 18%, placebo 2%) ^[1]^[2]^[3]^[5].
Clinicians should consult current prescribing information for full dosing guidance.
Decreased platelet count occurred (Trial 1: 5/43 [12%] vs 1/23 [4%]); mean percent changes in platelet count in the TRYNGOLZA 80 mg group were -10% at Week 53 versus +22% in the placebo group in Trial 1; no TRYNGOLZA-treated patient with FCS had platelet count <50,000/mm3 and there were no major bleeding events associated with low platelet counts ^[1]^[5].
Arthralgia was reported (Trial 1: 4/43 [9%] vs 0/23 [0%]) ^[1]^[5].
Increases in fasting glucose (≤17 mg/dL) and HbA1c (<0.2 percentage points) were observed over time in the FCS population; incidence of hyperglycemia was higher in olezarsen-treated patients without diabetes at baseline (52%) versus placebo (35%) in Trial 1 ^[1]^[5].
Increases in liver enzymes and hepatic fat fraction were observed; in sHTG trials, elevations ≥3× ULN were reported more frequently with TRYNGOLZA 80 mg (7%) compared with TRYNGOLZA 50 mg (3%) and placebo (3%); hepatic fat fraction increased dose-dependently at 12 months (mean +2 percentage points for 50 mg, +4 percentage points for 80 mg vs 0 for placebo in substudy) ^[2]^[3]^[5].
Increases in LDL-C and total apolipoprotein B were observed; most patients treated with TRYNGOLZA had maximum LDL-C <70 mg/dL (74%) in Trial 1 ^[1]^[5].

Study Design

The FCS approval was supported by a randomized, placebo-controlled, double-blind trial (Trial 1; NCT04568434) enrolling 66 adult patients with genetically identified FCS and fasting TG ≥880 mg/dL; patients were randomized to TRYNGOLZA 80 mg every 4 weeks (n=22) or placebo (n=23) over a 53-week treatment period, and the primary endpoint was percent change in fasting TG from baseline to Month 6 (average of Weeks 23, 25, and 27) ^[5]. The two sHTG trials (Trial 2, NCT05079919 and Trial 3, NCT05552326) were randomized, double-blind, placebo-controlled trials in adults with fasting TG ≥500 mg/dL and showed statistically significant percent TG reductions at Month 6 for 50 mg and 80 mg dosing ^[5]^[2]. Details on randomization stratification and analysis methods are provided in the full prescribing information ^[5]. Clinicians should consult current prescribing information for complete dosing guidance.

FAQ

Q1 What is TRYNGOLZA (olezarsen) approved for?

TRYNGOLZA is approved as an adjunct to diet to reduce triglycerides in adults with familial chylomicronemia syndrome (FCS). The prescribing information and FDA communication for the original approval date the action to 12/19/2024; supplemental labeling for severe hypertriglyceridemia (sHTG) appears in later DailyMed updates.

Q2 How does olezarsen work?

Olezarsen is an apolipoprotein C-III-directed antisense oligonucleotide conjugated to a GalNAc ligand that binds to apoC-III mRNA, leading to mRNA degradation and reduction in serum apoC-III protein; reduction of apoC-III increases clearance of plasma triglycerides and very low-density lipoprotein (VLDL).

Q3 What is the recommended dose of TRYNGOLZA?

For adults with familial chylomicronemia syndrome (FCS) the recommended dosage is 80 mg administered subcutaneously once monthly. For adults with severe hypertriglyceridemia (sHTG) the prescribing information lists a recommended starting dosage of 50 mg subcutaneously once monthly, with the option to increase to 80 mg once monthly if tolerated and additional TG reduction is clinically indicated. Clinicians should consult current prescribing information for complete dosing guidance.

Q4 What are the most common side effects?

The most common adverse reactions in clinical trials included injection site reactions, decreased platelet count, and arthralgia in patients with FCS; in sHTG trials the most commonly reported events were injection site reactions and increases in liver enzymes. Hypersensitivity reactions, reductions in platelet count, increases in liver enzymes and hepatic fat, increases in fasting glucose and LDL-C were observed and are described in the prescribing information.

FDA Approves Olezarsen for FCS: Cuts TG 43% vs Placebo

Direct Clinical Takeaway & Evidence Summary

FDA Approves Olezarsen for FCS: Cuts TG 43% vs Placebo

Clinical Perspective

Clinical Context

Key Findings

Safety & Tolerability

Study Design

FAQ

References

Get weekly clinical updates for Cardiology in your inbox.

Related Clinical Updates

FDA Approves Olezarsen for Severe Hypertriglyceridemia: Reduces TG and Pancreatitis Risk

FDA Approves Etripamil for PSVT: 64% 30‑min Conversion in RAPID

AZALEA–TIMI 71: Abelacimab Reduced Bleeding Risk (HR 0.38) vs Rivaroxaban in AF

Verified HCP Portal