SAPHNELO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SAPHNELO (SAPHNELO).

How it works

SAPHNELO (anifrolumab) is a human monoclonal antibody that binds to the type I interferon (IFN) receptor subunit 1 (IFNAR1), blocking the activity of all type I IFNs (including IFN-α, IFN-β, and IFN-κ). This inhibition reduces the downstream signaling and expression of interferon-stimulated genes, thereby decreasing inflammation and immune activation associated with systemic lupus erythematosus.

What the body does with it

Metabolism	Anifrolumab is a monoclonal antibody; it is degraded by catabolic pathways into small peptides and amino acids. No specific metabolic enzymes are involved.
Excretion	SAPHNELO (anifrolumab) is primarily eliminated via intracellular catabolism; no specific renal or biliary excretion data. As a monoclonal antibody, it is not excreted renally or hepatically.
Half-life	Terminal elimination half-life is approximately 27.4 days (range 17–34 days), supporting every-4-week dosing. Steady-state is reached by 10–12 weeks.
Protein binding	Primarily bound to endogenous IgG receptors (FcRn); specific protein binding data not available, but typical monoclonal antibody behavior with minimal binding to albumin or other plasma proteins.
Volume of Distribution	Volume of distribution is approximately 5.25 L (0.075 L/kg for a 70 kg adult), indicating distribution primarily within the vascular space and interstitial fluid.
Bioavailability	Subcutaneous: Approximately 86% (range 70–100%) relative to intravenous administration. Absolute bioavailability not determined due to lack of IV formulation data in humans.
Onset of Action	Subcutaneous: Clinical response observed as early as Week 4, with maximal effect typically by Week 12–24.
Duration of Action	Duration matches dosing interval (4 weeks) due to sustained receptor occupancy; effect may persist for 8–12 weeks after discontinuation due to slow clearance.

Classification & Brands

Dosing & administration

300 mg intravenously every 4 weeks, administered as a 1-hour infusion.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min/1.73 m²). 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 hepatic impairment (Child-Pugh class A). Not studied in moderate (Child-Pugh class B) or severe (Child-Pugh class C) hepatic impairment; use not recommended.
Pediatric use	Safety and efficacy in pediatric patients (age <18 years) have not been established; no approved dosing.
Geriatric use	No specific dose adjustment required based on age. Clinical studies included limited number of patients ≥65 years; no overall differences in safety or efficacy observed.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SAPHNELO (SAPHNELO).

Breastfeeding	No human data on excretion in milk; anifrolumab is a large monoclonal antibody expected to be present in low levels in breast milk. M/P ratio unknown; consider developmental and health benefits of breastfeeding vs. potential risk.
Teratogenic Risk	No adequate human data; in animal studies, anifrolumab crossed the placenta and caused increased fetal loss and reduced fetal weight at doses 6-10 times the human exposure. Based on mechanism (IFNAR blockade), potential for immune-mediated developmental harm; avoid in pregnancy unless benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Concurrent use with other biologic therapies (e.g., B-cell depleting agents) due to increased risk of infection.","Severe active infections (e.g., sepsis)."]

Clinical Precautions

Precautions

["Serious infections: Increased risk of infections, including herpes zoster and opportunistic infections. Do not administer during active infections.","Hypersensitivity reactions: Infusion-related reactions and allergic reactions have been reported.","Malignancy: Immunomodulatory effects may increase risk of malignancies.","Live vaccines: Should not be given concurrently with live vaccines.","Increase in major adverse cardiovascular events (MACE): Observed in clinical trials; use caution in patients with cardiovascular risk factors."]

Clinical Tips & Counseling

Drug interactions

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SAPHNELO

Clinical safety rating: caution

Comprehensive clinical and safety monograph for SAPHNELO (SAPHNELO).

How it works

What the body does with it

Metabolism	Anifrolumab is a monoclonal antibody; it is degraded by catabolic pathways into small peptides and amino acids. No specific metabolic enzymes are involved.
Excretion	SAPHNELO (anifrolumab) is primarily eliminated via intracellular catabolism; no specific renal or biliary excretion data. As a monoclonal antibody, it is not excreted renally or hepatically.
Half-life	Terminal elimination half-life is approximately 27.4 days (range 17–34 days), supporting every-4-week dosing. Steady-state is reached by 10–12 weeks.
Protein binding	Primarily bound to endogenous IgG receptors (FcRn); specific protein binding data not available, but typical monoclonal antibody behavior with minimal binding to albumin or other plasma proteins.
Volume of Distribution	Volume of distribution is approximately 5.25 L (0.075 L/kg for a 70 kg adult), indicating distribution primarily within the vascular space and interstitial fluid.
Bioavailability	Subcutaneous: Approximately 86% (range 70–100%) relative to intravenous administration. Absolute bioavailability not determined due to lack of IV formulation data in humans.
Onset of Action	Subcutaneous: Clinical response observed as early as Week 4, with maximal effect typically by Week 12–24.
Duration of Action	Duration matches dosing interval (4 weeks) due to sustained receptor occupancy; effect may persist for 8–12 weeks after discontinuation due to slow clearance.

Classification & Brands

Dosing & administration

300 mg intravenously every 4 weeks, administered as a 1-hour infusion.

Dosage form	INJECTABLE
Renal impairment	No dose adjustment required for mild to moderate renal impairment (eGFR ≥30 mL/min/1.73 m²). 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 hepatic impairment (Child-Pugh class A). Not studied in moderate (Child-Pugh class B) or severe (Child-Pugh class C) hepatic impairment; use not recommended.
Pediatric use	Safety and efficacy in pediatric patients (age <18 years) have not been established; no approved dosing.
Geriatric use	No specific dose adjustment required based on age. Clinical studies included limited number of patients ≥65 years; no overall differences in safety or efficacy observed.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for SAPHNELO (SAPHNELO).

Breastfeeding	No human data on excretion in milk; anifrolumab is a large monoclonal antibody expected to be present in low levels in breast milk. M/P ratio unknown; consider developmental and health benefits of breastfeeding vs. potential risk.
Teratogenic Risk	No adequate human data; in animal studies, anifrolumab crossed the placenta and caused increased fetal loss and reduced fetal weight at doses 6-10 times the human exposure. Based on mechanism (IFNAR blockade), potential for immune-mediated developmental harm; avoid in pregnancy unless benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

None.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Concurrent use with other biologic therapies (e.g., B-cell depleting agents) due to increased risk of infection.","Severe active infections (e.g., sepsis)."]