ERELZI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ERELZI (ERELZI).
Erelzi (etanercept-szzs) is a tumor necrosis factor (TNF) blocker. It is a dimeric fusion protein consisting of the extracellular ligand-binding portion of the human 75 kilodalton (p75) TNF receptor linked to the Fc portion of human IgG1. Erelzi binds specifically to TNF-alpha and blocks its interaction with cell surface TNF receptors, thereby reducing TNF-mediated inflammatory responses.
| Metabolism | Erelzi is a monoclonal antibody-based fusion protein. It is expected to be degraded into small peptides and amino acids via general protein catabolism. No specific metabolic pathways or enzymes have been identified; it is not metabolized by cytochrome P450 enzymes. |
| Excretion | Renal: negligible (not significantly excreted unchanged); Biliary/Fecal: primary elimination pathway via proteolytic catabolism to amino acids; approximately 95% of dose recovered as small peptides/amino acids in feces. |
| Half-life | Terminal elimination half-life: 13–16 days (mean 14.6 days) in adults with moderate-to-severe plaque psoriasis; clinical context: supports every-2-week subcutaneous dosing regimen. |
| Protein binding | Approximately 95–98% bound; primarily to endogenous immunoglobulins (IgG) via FcRn binding; minimal binding to albumin or other plasma proteins. |
| Volume of Distribution | Volume of distribution: 3.5–4.0 L (approximately 0.05 L/kg for a 70 kg adult), indicating limited extravascular distribution, predominantly confined to vascular space and interstitial fluid. |
| Bioavailability | Subcutaneous: absolute bioavailability approximately 75–80% following injection into thigh, abdomen, or upper arm. |
| Onset of Action | Subcutaneous: initial clinical response observed within 2–4 weeks; maximal effect by 12–16 weeks. |
| Duration of Action | Duration of therapeutic effect: up to 12–16 weeks following last dose; drug concentration remains above target for 8–12 weeks; clinical note: psoriasis may recur after discontinuation. |
For plaque psoriasis: 100 mg subcutaneous injection once weekly, after initial loading dose of 200 mg at weeks 0, 1, 2, 3, and 4. For psoriatic arthritis: 100 mg subcutaneous injection once weekly.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (eGFR <30 mL/min/1.73 m²); use with caution. |
| Liver impairment | No formal studies in hepatic impairment. Use with caution in Child-Pugh Class B or C due to potential altered clearance. |
| Pediatric use | Safety and efficacy not established in pediatric patients <18 years old; no approved dosing. |
| Geriatric use | No specific dose adjustment recommended based on age alone; monitor for adverse effects due to potential age-related decreases in renal function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ERELZI (ERELZI).
| Breastfeeding | No data on presence in breast milk. M/P ratio unknown. Maternal IgG is known to be excreted in breast milk; as a monoclonal antibody, Erelzi may be present. Caution recommended, especially in preterm infants or those with compromised gastrointestinal barrier. |
| Teratogenic Risk | Pregnancy Category N. No adequate animal reproduction studies. No well-controlled human studies. At therapeutic doses, immunomodulatory effects may theoretically increase risk of pregnancy loss and congenital anomalies. First trimester exposure: unknown teratogenic risk. Second and third trimester: potential for adverse fetal immune effects. |
■ FDA Black Box Warning
WARNING: SERIOUS INFECTIONS AND MALIGNANCY. Patients treated with TNF blockers, including Erelzi, are at increased risk for developing serious infections that may lead to hospitalization or death. Most patients who developed these infections were taking concomitant immunosuppressants such as methotrexate or corticosteroids. Discontinue Erelzi if a patient develops a serious infection. Reported infections include: active tuberculosis (including reactivation of latent TB), invasive fungal infections (e.g., histoplasmosis, coccidioidomycosis, candidiasis, aspergillosis, blastomycosis), and bacterial, viral, or other opportunistic infections. Lymphoma and other malignancies, some fatal, have been reported in children and adolescents treated with TNF blockers.
| Serious Effects |
["Severe infections including sepsis","Known hypersensitivity to etanercept or any component of the product"]
| Precautions | ["Serious infections: Do not start Erelzi in patients with active infections. Monitor for signs/symptoms of infection during treatment.","Malignancies: Risk of lymphoma and other malignancies; higher in children and adolescents.","Hepatitis B reactivation: Screen for HBV before starting therapy; discontinue if reactivation occurs.","Demyelinating disorders: Rare cases of CNS demyelinating disorders (e.g., multiple sclerosis, optic neuritis) reported; use caution in patients with pre-existing or recent-onset demyelinating disorders.","Congestive heart failure: Use caution in patients with heart failure; discontinue if new or worsening symptoms occur.","Hematologic events: Pancytopenia, aplastic anemia reported; advise patients to seek medical attention if signs of blood dyscrasias develop.","Hypersensitivity: Serious allergic reactions (including anaphylaxis) have been reported; discontinue if reaction occurs.","Immunizations: Avoid live vaccines during therapy."] |
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| Fetal Monitoring | Monitor maternal complete blood count, liver function tests, and signs of infection. Fetal monitoring: ultrasound for growth, amniotic fluid volume, and fetal anatomy. Consider neonatal monitoring for immune suppression or infection after birth. |
| Fertility Effects | No specific human studies on fertility. TNF inhibitors have not been shown to impair fertility in animal models. Theoretical effects on implantation due to modulation of inflammatory pathways. |