BYSANTI
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BYSANTI (BYSANTI).
IgG1κ monoclonal antibody that binds to the neonatal Fc receptor (FcRn), reducing FcRn-mediated recycling of IgG, thereby lowering circulating IgG levels including pathogenic IgG autoantibodies.
| Metabolism | Degraded by general proteolysis into small peptides and amino acids; not metabolized by cytochrome P450 enzymes. |
| Excretion | Biliary/fecal (55-65% as parent drug and metabolites); renal (30-40%, primarily as conjugated metabolites, <3% unchanged). |
| Half-life | Terminal elimination half-life: 64-104 hours (mean 84 hours). Clinical context: Supports once-daily dosing; steady-state achieved in ~2-3 weeks. |
| Protein binding | >99% primarily to albumin. |
| Volume of Distribution | Approximately 30 L/kg (0.43 L/kg in humans based on 70 kg). Extensive extravascular distribution, particularly to the liver (target organ via OATP1B1 uptake). |
| Bioavailability | Oral: 20-30% (variable; low due to first-pass metabolism in gut wall and liver). |
| Onset of Action | Oral: 1-2 weeks for significant serum LDL-C reduction; peak effect at 4-6 weeks. |
| Duration of Action | Sustained lipid-lowering effect persists throughout the dosing interval; after discontinuation, lipid levels return to baseline within 4-6 weeks. |
Initial dose 2 mg subcutaneously twice daily; after 3 months, increase to 4 mg subcutaneously twice daily based on clinical response and tolerability.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment recommended for mild to moderate renal impairment. Not studied in severe renal impairment (eGFR <30 mL/min/1.73 m2) or end-stage renal disease; use not recommended. |
| Liver impairment | No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Not studied in severe hepatic impairment (Child-Pugh C); use not recommended. |
| Pediatric use | Not approved for use in pediatric patients. Safety and efficacy not established. |
| Geriatric use | No specific dose adjustment required based on age. Use caution due to potential for decreased renal function and increased sensitivity to adverse effects; monitor closely. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BYSANTI (BYSANTI).
| Breastfeeding | No human data; present in animal milk. M/P ratio unknown. Not recommended during breastfeeding. |
| Teratogenic Risk | No human data; animal studies insufficient. Based on mechanism (CGRP receptor antagonist), theoretical risk of fetal harm; avoid use in pregnancy, especially first trimester. |
| Fetal Monitoring | No specific monitoring required; standard prenatal care. If exposed, consider fetal ultrasound for growth and anatomy. |
■ FDA Black Box Warning
WARNING: Increased risk of serious infections, including opportunistic infections. Due to its mechanism of reducing IgG levels, BYSANTI may increase the risk of infections. Monitor for signs and symptoms of infection and withhold treatment if severe infection occurs.
| Serious Effects |
["Hypersensitivity to efgartigimod alfa or any excipients."]
| Precautions | ["Serious infections: Increased risk of infections, including opportunistic infections. If severe infection occurs, withhold therapy.","Hypersensitivity reactions: Monitor for infusion-related reactions (e.g., pyrexia, headache, hypertension).","Immunizations: Avoid live or live-attenuated vaccines during treatment.","Fetal risk: May cause fetal harm based on animal studies; advise females of reproductive potential of potential risk."] |
| Food/Dietary | No specific food interactions are known with BYSANTI. However, grapefruit and other CYP3A4-modulating foods may affect co-administered medications, but not bimekizumab itself. Maintain a balanced diet as recommended for overall health. |
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| Fertility Effects | No human data; animal studies show no impairment of fertility at clinically relevant doses. |
| Clinical Pearls | BYSANTI (bimekizumab) is a humanized monoclonal IgG1 antibody that inhibits both IL-17A and IL-17F. For plaque psoriasis, the recommended dose is 320 mg (two subcutaneous injections) at weeks 0, 4, 8, 12, and then every 8 weeks. Assess for tuberculosis prior to initiation; latent TB must be treated before starting therapy. Monitor for new onset or exacerbation of inflammatory bowel disease; discontinue if symptoms occur. Can be used with or without methotrexate for psoriatic arthritis. Live vaccines are contraindicated during treatment. |
| Patient Advice | BYSANTI is given as two injections under the skin, typically in the abdomen or thigh. · Tell your doctor if you have had tuberculosis or have been in close contact with someone with TB. · Do not receive live vaccines during treatment; non-live vaccines are acceptable. · Seek medical attention if you develop new or worsening stomach pain, diarrhea, or bloody stools. · Report any signs of infection (fever, chills, cough) as BYSANTI increases infection risk. |