Evinacumab

Mechanism of Action

Mechanism of Action

Angiopoietin-like 3 (ANGPTL3) plays a prominent role in regulating lipid metabolism by blocking lipoprotein lipase and endothelial lipase. In HoFH, LDL-C levels increase because the low-density lipoprotein receptor (LDLR) function is diminished or absent, slowing or preventing LDL clearance. Evinacumab is a monoclonal antibody that binds to ANGPTL3, thereby allowing LPL, lipoprotein lipase, and endothelial lipase to enhance the clearance of very low-density lipoprotein (VLDL) remnants via remnant receptors in the liver, resulting in decreased LDL-C levels in an LDLR-independent manner.[8] This novel therapeutic approach stemmed from patients with a loss-of-function mutation in the angiopoietin-like 3 gene (ANGPTL3), who were noted to have decreased LDL-C, triglyceride, and high-density lipoprotein levels. Patients with this loss-of-function mutation also had reduced cardiovascular risk compared with those without the loss-of-function mutation.[9] 

Evinacumab has demonstrated broad effects on triglyceride-rich lipoprotein metabolism. Results from a 2024 post hoc analysis of 3 randomized clinical trials found that mean triglyceride-rich lipoprotein levels decreased, with reductions of 50% or greater observed at the highest doses.[10] Additionally, decreases in apolipoprotein C3 and apolipoprotein B100 levels have been observed with evinacumab therapy. Clinicians should be aware that in patients with severe hypertriglyceridemia, LDL-C levels may appear to increase during treatment, likely because of enhanced conversion of VLDL to LDL during clearance of triglyceride-rich lipoproteins. [11]

Pharmacokinetics

Absorption: A steady-state concentration of evinacumab is achieved after 4 doses. For adults, population pharmacokinetic modeling reveals an average steady-state trough concentration of 266 mg/L with a standard deviation of 120 mg/L.

Distribution: The estimated steady-state volume of distribution, determined through population pharmacokinetic analysis, is approximately 4.7 L.

Metabolism: The metabolic pathway for evinacumab remains uncharacterized. Evinacumab is a human monoclonal IgG4 antibody; it is believed to be degraded into small peptides and amino acids, similar to endogenous IgG, via catabolic pathways.

Excretion: Evinacumab, a monoclonal antibody, is unlikely to be renally excreted. The elimination half-life of evinacumab is linked to its serum concentration, with an approximate duration of 20 weeks for the serum concentration to decrease below the lower detection limit.

Administration

Dosage Forms

Evinacumab should be administered to patients with HoFH via intravenous infusion. For proper storage, evinacumab injection should be refrigerated at 36 °F to 46 °F (2 °C to 8 °C). The vial should be kept in its original carton to protect it from light exposure. Clinicians should avoid freezing or shaking the vial.

Strength

Two standard single-dose vial preparations are available: 345 mg/2.3 mL (150 mg/mL) and 1200 mg/8 mL (150 mg/mL). The dosage should be calculated based on the patient's weight, and the prepared volume should be determined accordingly. Clinicians should withdraw the necessary quantity and transfer it into an intravenous infusion bag with a capacity of up to 250 mL, containing 0.9% sodium chloride USP or 5% dextrose injection. The diluted solution should be gently inverted to mix; clinicians should not shake the solution.

Adult Dosage

The recommended dosage is 15 mg/kg of body weight, administered once every 4 weeks by intravenous infusion over 60 minutes.[7]

Specific Patient Populations

Hepatic impairment: No clinical data are currently available.

Renal impairment: Although the definitive metabolic pathway of evinacumab is unknown, evinacumab is not thought to undergo renal clearance. Results from preliminary studies showed that patients with mild to moderate renal impairment demonstrated steady-state concentrations similar to those in patients with normal renal function. Dose adjustment is unnecessary for mild to moderate renal impairment. Data are lacking for patients with severe renal impairment.

Pregnancy considerations:  Special consideration is needed for pregnant patients because some animal models demonstrate the potential for fetal toxicity, including malformations during organogenesis. Human data are not available to evaluate the risk to the embryo and fetus; patients should be aware of potential risks. Patients who start the medication should be counseled on contraceptive methods due to potential teratogenic risks. All patients at risk of becoming pregnant should be monitored closely and counseled on the risk of pregnancy while receiving treatment with evinacumab.

Breastfeeding considerations: No known risk has been established for breastfeeding patients. Due to the high molecular weight of 146,000 Da, the presence of evinacumab in breast milk is expected to be minimal. Furthermore, the protein may be degraded in the infant's gastrointestinal tract, limiting absorption. Without further information, cautious use of evinacumab is advised during breastfeeding, particularly when nursing a neonate or preterm infant.[12]

Pediatric and geriatric patients:  No dosage adjustment is needed; the same ratio can be used to calculate the appropriate dosage for pediatric and older patients who meet the guidelines for initiating an evinacumab treatment regimen. Patients aged 65 years and older should be carefully evaluated before being prescribed evinacumab.

Adverse Effects

Adverse Effects

Common adverse effects reported in patients receiving evinacumab include hypersensitivity reactions, nasopharyngitis, nausea, influenza-like illness, dizziness, extremity pain, and rhinorrhea.[13] Injection site reactions to evinacumab include erythema, pain, bruising, swelling, induration, rash, and pruritus.[14] Anaphylaxis was the most severe adverse effect reported in clinical trials.[15] Clinical trial findings have not shown evidence that evinacumab alters hepatic or renal function, as evidenced by stable plasma concentrations of aspartate aminotransferase, alanine aminotransferase, and creatine kinase throughout the treatment periods.[14] Another potential complication of all monoclonal antibody treatments is immunogenicity. However, no patients in the clinical trials developed treatment-emergent antidrug antibodies against evinacumab.

In patients with severe hypertriglyceridemia treated with evinacumab, LDL-C levels have been reported to increase. The increase in LDL-C is thought to result from enhanced conversion of VLDL particles into LDL particles, as evinacumab promotes upstream clearance of triglyceride-rich lipoproteins. The increase in LDL-C levels is consistent with the drug's mechanism of action and should be distinguished from a true adverse lipid effect.

Drug-Drug Interactions

No significant drug interactions with evinacumab have been identified. In a clinical trial, the concentrations of simvastatin, atorvastatin, and rosuvastatin were not significantly altered when coadministered with evinacumab. Further drug interaction studies should be conducted.

Contraindications

Contraindications

Evinacumab is contraindicated in patients with severe hypersensitivity reactions such as anaphylaxis.[16] Patients with a history of allergic reactions to any excipients in evinacumab should not be prescribed the medication.

Warning and Precautions

Embryofetal toxicity: Evinacumab poses a potential risk for embryofetal toxicity. Patients receiving evinacumab should use contraceptive methods throughout the therapeutic interval and for 5 months following the last dose of evinacumab therapy.

Hypersensitivity reactions: Evinacumab has been linked to severe hypersensitivity reactions, including anaphylaxis. If significant hypersensitivity signs or symptoms emerge, clinicians should stop the evinacumab infusion, administer standard-of-care treatment, and monitor the patient until resolution.[17]

Monitoring

Throughout evinacumab therapy, lipid panels should be routinely obtained to measure triglyceride, LDL-C, and total cholesterol levels. LDL-C levels may be checked as early as 2 weeks after initiating evinacumab therapy to assess whether LDL-C levels have decreased. Patients should be evaluated regularly by their prescribing clinician to monitor laboratory values and ensure no adverse effects have occurred since the last infusion. If a scheduled evinacumab infusion is missed, patients should receive the infusion as soon as possible. Following the previous dosage, regular monthly infusions should be rescheduled to ensure continued treatment effectiveness. Routine administration and follow-up appointments with the clinician are vital to providing safe and effective evinacumab treatment. Because severe hypersensitivity reactions have occurred with evinacumab, clinicians should discontinue the evinacumab infusion if signs or symptoms of severe allergic reactions occur. Clinicians should treat the hypersensitivity reaction per standard-of-care protocols and observe the patient until signs and symptoms resolve.[4] Additionally, patients should be advised to begin or continue lifestyle modifications, such as diet and exercise, to further lower LDL-C levels.

Toxicity

There is no significant toxicity associated with evinacumab therapy apart from embryofetal toxicity.[18] No antidote to evinacumab exists. No known contraindications apply to patients with renal or hepatic impairment. Further studies should be performed to more accurately assess any long-term complications or adverse effects that may arise from evinacumab therapy.[19][20] Results from a 2024 systematic review and meta-analysis of 4 randomized controlled trials evaluated the safety and efficacy of evinacumab across diverse patient populations. The analysis demonstrated significant reductions in multiple lipid markers, and adverse event findings revealed no statistically significant safety concerns, supporting the favorable tolerability profile established in earlier studies.[21] If patients experience adverse reactions to evinacumab, they should consult their prescribing or primary care clinician as quickly as possible or seek immediate emergency care.

Enhancing Healthcare Team Outcomes

HoFH is a hereditary condition that negatively affects lipid metabolism. HoFH is associated with high cholesterol, particularly elevated LDL-C. High cholesterol levels predispose patients to early cardiovascular disease, which may lead to increased atherosclerosis. Increased atherosclerosis can lead to the development of either stroke or myocardial infarction.

Evinacumab is a novel monoclonal antibody medication used to treat HoFH. This medication may effectively treat patients with inadequate responses to more conventional pharmacologic treatments and lifestyle modifications. Evinacumab effectively lowers LDL-C levels in patients with HoFH. Evinacumab may be most effective when used with other lipid-lowering medications and dietary and lifestyle modifications to achieve optimal results.[22]

Evinacumab requires prior authorization before administration, with specific guidelines that may vary by insurance company. Another critical factor to consider before administering evinacumab is cost.[23] Due to the novelty of the medication, the expense of evinacumab may be quite high, with the annual wholesale cost as high as $450,000. Citing the substantial price of $450,000 per patient per year for evinacumab, the National Lipid Association emphasizes the need for cost-effective approaches and proposes a novel technique: customizing doses using weight bands, departing from the conventional mg/kg method and from dose individualization based on LDL-C response. This method can achieve a 34% cost reduction without compromising efficacy and offers a promising strategy to reduce the financial burden.[24] 

Treatment of HoFH usually requires the expertise of cardiologists and endocrinologists. However, primary care clinicians are essential to the optimal care of patients with HoFH because they routinely check laboratory values, including lipid panels. Pharmacists also play an indispensable role in treating HoFH; multiple lipid-lowering therapies must be rigorously trialed before initiating evinacumab therapy.

Other healthcare team members integral to evinacumab therapy include nurses, many of whom will start intravenous lines and initiate infusion therapy. Many nurses will be responsible for preparing the infusion and ensuring proper dosage and administration. Patients should feel comfortable with their treatment plan and receive informed consent for all risks and benefits before initiating treatment. In the event of anaphylaxis, emergency department clinicians should rapidly stabilize the patient. An interprofessional team approach with open communication among primary care clinicians, specialists, nurses, and pharmacists can optimize patient outcomes with evinacumab therapy.