ARRANON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ARRANON (ARRANON).
Purine nucleoside analog; after intracellular phosphorylation to ara-GTP, it incorporates into DNA, inhibits DNA synthesis, and induces apoptosis in T-cell progenitors.
| Metabolism | Intracellular deamination by cytidine deaminase; minimal hepatic metabolism via CYP450. |
| Excretion | Nelarabine is extensively metabolized to ara-G; elimination is primarily renal: ~27% as parent drug and 30-50% as ara-G in urine. Fecal excretion accounts for <5% of administered dose. |
| Half-life | Terminal elimination half-life of nelarabine is approximately 30 minutes; the active metabolite ara-G has a terminal half-life of approximately 20-24 hours. Clinically, this supports daily dosing in cycles. |
| Protein binding | Nelarabine is <25% bound to plasma proteins; ara-G is approximately 30% bound. Binding proteins include albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Nelarabine: mean Vd ~33 L/m² (approx 0.8-1.0 L/kg in adults); ara-G: Vd ~40 L/m². Indicates extensive distribution into total body water and tissues. |
| Bioavailability | Intravenous only; bioavailability is 100% by IV route. No oral formulation is available. |
| Onset of Action | Intravenous administration: Clinical effects (antileukemic activity) are observed within days to a week, with peak reduction of blasts typically seen after completion of a 5-day cycle. |
| Duration of Action | The pharmacodynamic effect (cytotoxicity) persists for days after drug clearance, due to intracellular accumulation of ara-G nucleotides. Duration of single-cycle effect can last several weeks, allowing for intermittent dosing schedules. |
2600 mg/m2 intravenously over 2 hours on days 1, 3, and 5, repeated every 28 days.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment recommended for renal impairment; use caution in severe renal impairment (CrCl < 30 mL/min) due to lack of data. |
| Liver impairment | Child-Pugh Class A: 2600 mg/m2. Child-Pugh Class B: Reduce dose by 50% to 1300 mg/m2. Child-Pugh Class C: Avoid use due to lack of data. |
| Pediatric use | Safety and efficacy not established in pediatric patients; no standard dosing available. |
| Geriatric use | No specific dose adjustment recommended; monitor for increased toxicity (e.g., neurotoxicity, myelosuppression) due to age-related organ function decline. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ARRANON (ARRANON).
| Breastfeeding | No data on M/P ratio; likely excreted in human milk due to low molecular weight, but unknown. Discontinue breastfeeding during therapy due to potential serious adverse reactions in nursing infants. |
| Teratogenic Risk | Pregnancy Category D. First trimester: evidence of fetal risk based on animal studies and human data; second and third trimesters: continued risk, including myelosuppression and teratogenicity. Avoid use unless benefit outweighs risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
Neurologic toxicity: severe, life-threatening neurologic reactions including coma, seizures, and peripheral neuropathy have occurred; dose reduction or discontinuation may be required.
| Serious Effects |
Hypersensitivity to nelarabine or any component of the formulation.
| Precautions | Neurologic toxicity (somnolence, confusion, ataxia, paralysis); bone marrow suppression; embryo-fetal toxicity; tumor lysis syndrome; pancreatitis; elevated liver enzymes. |
| Food/Dietary | Avoid foods high in riboflavin (beef liver, fortified cereals, dairy) and NADH precursors as they may reduce drug efficacy. No known significant food interactions with standard diets. Maintain adequate hydration. |
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| Monitor complete blood counts (CBC) with differential weekly during induction and periodically during consolidation; monitor liver function tests (AST, ALT, bilirubin) and serum creatinine; monitor for signs of infection, bleeding, and neurological toxicity (seizures, peripheral neuropathy). Fetal monitoring: ultrasound for growth and anatomy if used in pregnancy. |
| Fertility Effects | Nelarabine may cause reduced fertility in males and females based on animal studies; human data limited. Potential for gonadal suppression and irreversible infertility; consider fertility preservation prior to treatment. |
| Clinical Pearls | Monitor for severe neurological toxicity including somnolence, confusion, and ataxia; discontinue if grade ≥3. Administer over 2 hours intravenously; do not use with flavin adenine dinucleotide (FAD) or NADH supplements due to potential antagonism. Premedicate with antiemetics. Contraindicated in patients with G6PD deficiency due to risk of hemolysis. |
| Patient Advice | Report any new or worsening drowsiness, confusion, dizziness, or difficulty walking immediately. · Avoid driving or operating machinery if you experience drowsiness or dizziness. · Do not take supplements containing riboflavin (vitamin B2) or NADH without consulting your doctor. · You may need blood tests to monitor your blood counts and liver function regularly. · Notify your doctor if you have a history of glucose-6-phosphate dehydrogenase (G6PD) deficiency or if you experience yellowing of skin or eyes. |