NELARABINE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NELARABINE (NELARABINE).

How it works

Nelarabine is a prodrug of ara-G, a deoxyguanosine analog. It is converted to ara-GTP, which accumulates in T-cells and inhibits DNA synthesis, leading to cell death.

What the body does with it

Metabolism	Nelarabine is demethylated by adenosine deaminase (ADA) to ara-G, which is then phosphorylated to ara-GTP intracellularly. It is partially metabolized by aldehyde oxidase.
Excretion	Renal: 50-60% as unchanged ara-G; fecal: <5% as metabolites; biliary: negligible.
Half-life	Terminal t1/2: 30 hours (range 21-48 h) in adults; prolonged in renal impairment. Ara-G (active metabolite) t1/2: 3 hours.
Protein binding	<25% bound to plasma proteins (albumin).
Volume of Distribution	Vd: 197 L/m² (approx 5.6 L/kg based on 1.73 m²/70 kg), indicating extensive tissue distribution.
Bioavailability	IV only; oral bioavailability not established (<5% due to extensive first-pass metabolism).
Onset of Action	IV: Clinical response (e.g., reduction in blasts) observed within 1-2 weeks after first dose; peak plasma concentration occurs at end of infusion.
Duration of Action	Duration of response variable; typical cycle length 21-28 days with dosing on days 1, 3, 5. Cytotoxic effects persist for several days post-infusion.

Classification & Brands

Dosing & administration

1500 mg/m2 intravenously over 2 hours on days 1, 3, and 5, repeated every 28 days.

Dosage form	INJECTABLE
Renal impairment	CrCl 30-60 mL/min: reduce dose to 975 mg/m2. CrCl <30 mL/min: not recommended.
Liver impairment	Child-Pugh Class B or C: reduce dose to 975 mg/m2. No data for severe impairment.
Pediatric use	650 mg/m2 intravenously over 1 hour daily for 5 consecutive days, repeated every 21 days.
Geriatric use	No specific dose adjustment recommended; monitor renal function and hematologic toxicity closely.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for NELARABINE (NELARABINE).

Breastfeeding

No human data on nelarabine excretion in breast milk. Due to its mechanism of action (DNA synthesis inhibition) and potential for serious adverse effects in the nursing infant, breastfeeding is contraindicated during therapy and for at least 3 months after the last dose.

Teratogenic Risk

Nelarabine is embryotoxic and fetotoxic in animal studies. It is classified as FDA Pregnancy Category D. There is evidence of fetal harm in pregnant women, including increased risk of congenital malformations, intrauterine growth restriction, and fetal death. Use during the first trimester carries highest risk of major malformations; second and third trimester exposure may cause myelosuppression and low birth weight. Avoid in pregnancy unless benefit outweighs risk.

Warnings & precautions

■ FDA Black Box Warning

Severe neurotoxicity, including Guillain-Barré-like syndrome, peripheral neuropathy, and CNS demyelination. Avoid in patients with severe pre-existing neurological conditions.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to nelarabine or its components.","Severe pre-existing neurological disorders (e.g., Guillain-Barré syndrome, peripheral neuropathy).","Pregnancy (may cause fetal harm)."]

Clinical Precautions

Precautions

["Monitor for neurological toxicity; may require discontinuation.","Hematologic toxicity: neutropenia, thrombocytopenia, anemia.","Increased risk of infection.","Tumor lysis syndrome prophylaxis required.","Hepatotoxicity and renal toxicity."]

Clinical Tips & Counseling

Drug interactions

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NELARABINE

Clinical safety rating: caution

Comprehensive clinical and safety monograph for NELARABINE (NELARABINE).

How it works

Nelarabine is a prodrug of ara-G, a deoxyguanosine analog. It is converted to ara-GTP, which accumulates in T-cells and inhibits DNA synthesis, leading to cell death.

What the body does with it

Metabolism	Nelarabine is demethylated by adenosine deaminase (ADA) to ara-G, which is then phosphorylated to ara-GTP intracellularly. It is partially metabolized by aldehyde oxidase.
Excretion	Renal: 50-60% as unchanged ara-G; fecal: <5% as metabolites; biliary: negligible.
Half-life	Terminal t1/2: 30 hours (range 21-48 h) in adults; prolonged in renal impairment. Ara-G (active metabolite) t1/2: 3 hours.
Protein binding	<25% bound to plasma proteins (albumin).
Volume of Distribution	Vd: 197 L/m² (approx 5.6 L/kg based on 1.73 m²/70 kg), indicating extensive tissue distribution.
Bioavailability	IV only; oral bioavailability not established (<5% due to extensive first-pass metabolism).
Onset of Action	IV: Clinical response (e.g., reduction in blasts) observed within 1-2 weeks after first dose; peak plasma concentration occurs at end of infusion.
Duration of Action	Duration of response variable; typical cycle length 21-28 days with dosing on days 1, 3, 5. Cytotoxic effects persist for several days post-infusion.

Classification & Brands

Dosing & administration

1500 mg/m2 intravenously over 2 hours on days 1, 3, and 5, repeated every 28 days.

Dosage form	INJECTABLE
Renal impairment	CrCl 30-60 mL/min: reduce dose to 975 mg/m2. CrCl <30 mL/min: not recommended.
Liver impairment	Child-Pugh Class B or C: reduce dose to 975 mg/m2. No data for severe impairment.
Pediatric use	650 mg/m2 intravenously over 1 hour daily for 5 consecutive days, repeated every 21 days.
Geriatric use	No specific dose adjustment recommended; monitor renal function and hematologic toxicity closely.

Use during pregnancy

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

Clinical note

Comprehensive clinical and safety monograph for NELARABINE (NELARABINE).

Breastfeeding

Teratogenic Risk

Warnings & precautions

■ FDA Black Box Warning

Severe neurotoxicity, including Guillain-Barré-like syndrome, peripheral neuropathy, and CNS demyelination. Avoid in patients with severe pre-existing neurological conditions.

Side Effect Profile

Serious Effects

Absolute Contraindications

["Hypersensitivity to nelarabine or its components.","Severe pre-existing neurological disorders (e.g., Guillain-Barré syndrome, peripheral neuropathy).","Pregnancy (may cause fetal harm)."]