GAMIFANT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for GAMIFANT (GAMIFANT).

How it works

Gamifant (emapalumab) is a fully human anti-interferon gamma (IFNγ) monoclonal antibody that neutralizes IFNγ and inhibits its binding to the IFNγ receptor, thereby blocking downstream signaling and the hyperinflammatory response in hemophagocytic lymphohistiocytosis (HLH).

What the body does with it

Metabolism	Emapalumab is a monoclonal antibody expected to be degraded into small peptides and amino acids via catabolic pathways; no specific metabolic enzymes involved.
Excretion	Gamifant (emapalumab) is largely catabolized into small peptides and amino acids. No significant renal or biliary excretion of intact drug. Clearance is primarily via reticuloendothelial system and target-mediated elimination.
Half-life	Terminal elimination half-life is approximately 22.6 days (range 13.6–39.5 days). This long half-life supports weekly dosing and allows sustained neutralization of interferon gamma.
Protein binding	Approximately 99% bound to plasma proteins (immunoglobulin G structure).
Volume of Distribution	Volume of distribution (Vd) is approximately 4.6–5.8 L, consistent with distribution primarily in the vascular space and limited extravascular distribution.
Bioavailability	Intravenous: 100% (only route of administration).
Onset of Action	Intravenous: Clinical response (improvement in HLH symptoms, decrease in ferritin and sCD25) typically observed within 1–2 weeks after starting treatment.
Duration of Action	Duration of action extends beyond the dosing interval due to long half-life; therapeutic effect persists for weeks after last dose. Clinical monitoring of HLH parameters guides treatment duration.

Classification & Brands

Dosing & administration

200 mg orally twice daily for 4 weeks, then 200 mg once daily for maintenance.

Dosage form	INJECTABLE
Renal impairment	GFR 30-89 mL/min: 200 mg once daily; GFR <30 mL/min or dialysis: contraindicated.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 200 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Weight ≥10 kg: 6 mg/kg/dose (max 200 mg) twice daily for 4 weeks, then 6 mg/kg once daily; weight <10 kg: not established.
Geriatric use	No specific dose adjustment; monitor renal function and use lowest effective dose due to increased sensitivity.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for GAMIFANT (GAMIFANT).

Breastfeeding	Unknown if excreted in human milk. M/P ratio not available. Consider developmental benefits of breastfeeding vs. maternal need for Gamifant and potential adverse effects on infant (immunosuppression). No data.
Teratogenic Risk	Gamifant (emapalumab) is a monoclonal antibody. No adequate studies in pregnant women. Based on mechanism (IFNγ blockade), may cause fetal harm. First trimester: potential for altered immune development. Second/third trimester: risk of fetal immunosuppression. Avoid unless benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Known severe hypersensitivity to emapalumab or any excipients.","Active severe infections (except those related to HLH) should be controlled prior to initiation."]

Clinical Precautions

Precautions

["Serious infections: Patients may develop severe infections due to immunosuppression; monitor for signs of infection and manage promptly.","Infusion-related reactions: Monitor during infusion; may require interruption or discontinuation.","Immunizations: Avoid live vaccines during and after therapy.","Potential for reactivation of latent infections (e.g., tuberculosis, hepatitis B) - screen before initiation."]

Clinical Tips & Counseling

Drug interactions

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GAMIFANT

Clinical safety rating: caution

Comprehensive clinical and safety monograph for GAMIFANT (GAMIFANT).

How it works

What the body does with it

Metabolism	Emapalumab is a monoclonal antibody expected to be degraded into small peptides and amino acids via catabolic pathways; no specific metabolic enzymes involved.
Excretion	Gamifant (emapalumab) is largely catabolized into small peptides and amino acids. No significant renal or biliary excretion of intact drug. Clearance is primarily via reticuloendothelial system and target-mediated elimination.
Half-life	Terminal elimination half-life is approximately 22.6 days (range 13.6–39.5 days). This long half-life supports weekly dosing and allows sustained neutralization of interferon gamma.
Protein binding	Approximately 99% bound to plasma proteins (immunoglobulin G structure).
Volume of Distribution	Volume of distribution (Vd) is approximately 4.6–5.8 L, consistent with distribution primarily in the vascular space and limited extravascular distribution.
Bioavailability	Intravenous: 100% (only route of administration).
Onset of Action	Intravenous: Clinical response (improvement in HLH symptoms, decrease in ferritin and sCD25) typically observed within 1–2 weeks after starting treatment.
Duration of Action	Duration of action extends beyond the dosing interval due to long half-life; therapeutic effect persists for weeks after last dose. Clinical monitoring of HLH parameters guides treatment duration.

Classification & Brands

Dosing & administration

200 mg orally twice daily for 4 weeks, then 200 mg once daily for maintenance.

Dosage form	INJECTABLE
Renal impairment	GFR 30-89 mL/min: 200 mg once daily; GFR <30 mL/min or dialysis: contraindicated.
Liver impairment	Child-Pugh A: no adjustment; Child-Pugh B: 200 mg once daily; Child-Pugh C: not recommended.
Pediatric use	Weight ≥10 kg: 6 mg/kg/dose (max 200 mg) twice daily for 4 weeks, then 6 mg/kg once daily; weight <10 kg: not established.
Geriatric use	No specific dose adjustment; monitor renal function and use lowest effective dose due to increased sensitivity.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for GAMIFANT (GAMIFANT).

Breastfeeding	Unknown if excreted in human milk. M/P ratio not available. Consider developmental benefits of breastfeeding vs. maternal need for Gamifant and potential adverse effects on infant (immunosuppression). No data.
Teratogenic Risk	Gamifant (emapalumab) is a monoclonal antibody. No adequate studies in pregnant women. Based on mechanism (IFNγ blockade), may cause fetal harm. First trimester: potential for altered immune development. Second/third trimester: risk of fetal immunosuppression. Avoid unless benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Known severe hypersensitivity to emapalumab or any excipients.","Active severe infections (except those related to HLH) should be controlled prior to initiation."]