Eflornithine Hydrochloride

What it is and how it works

Mechanism of Action Eflornithine is an irreversible inhibitor of the enzyme ornithine decarboxylase (ODC), the first and rate-limiting enzyme in the biosynthesis of polyamines and a transcriptional target of MYCN . Polyamines are involved in differentiation and proliferation of mammalian cells and are important for neoplastic transformation. Inhibition of polyamine synthesis by eflornithine restored the balance of the LIN28/Let-7 metabolic pathway, which is involved in regulation of cancer stem cells and glycolytic metabolism, by decreasing expression of the oncogenic drivers MYCN and LIN28B in MYCN -amplified neuroblastoma.

Indications

(eflornithine) is indicated to reduce the risk of relapse in adult and pediatric patients with high-risk neuroblastoma (HRNB) who have demonstrated at least a partial response to prior multiagent, multimodality therapy including anti-GD2 immunotherapy. IWILFIN is an ornithine decarboxylase inhibitor indicated to reduce the risk of relapse in adult and pediatric patients with high-risk neuroblastoma (HRNB) who have demonstrated at least a partial response to prior multiagent, multimodality therapy including anti-GD2 immunotherapy.

Dosage and administration (summary)

Prior to initiation of IWILFIN, perform baseline audiogram, complete blood count, and liver function tests. ( 2.1 , 5.3 ) Recommended dosage of IWILFIN is based on body surface area (see Table 1 ). IWILFIN is taken orally twice daily with or without food until disease progression, unacceptable toxicity, or for a maximum of two years. IWILFIN tablets may be swallowed whole, chewed, or crushed and mixed with soft food or liquid. Recommended Testing Before Initiating IWILFIN Prior to initiating IWILFIN, perform complete blood count, liver function tests, and baseline audiogram .

Contraindications

None. None

Warnings and precautions

Myelosuppression: Monitor blood counts before and during treatment with IWILFIN. Withhold, reduce dose, or permanently discontinue based on severity. Hepatotoxicity: Monitor liver function tests before and during treatment with IWILFIN. Withhold, reduce dose, or permanently discontinue based on severity. Hearing Loss: Monitor hearing before and during treatment with IWILFIN. Withhold, reduce dose, or permanently discontinue based on severity. Embryo-Fetal Toxicity: Can cause fetal harm.

Pregnancy

Pregnancy Risk Summary Based on findings from animal studies and its mechanism of action , IWILFIN can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, oral administration of eflornithine to pregnant rats and rabbits during the period of organogenesis resulted in embryolethality at doses equivalent to the reco…

Storage and supply

Store at room temperature, 20°C to 25°C (68°F to77°F), excursions permitted between 15°C to 30°C (59°F to 86°F) .

Source: Eflornithine Hydrochloride (Iwilfin) — US FDA prescribing information, 2026-03-26, DailyMed. Summarised and shortened; the full label governs. Iranian registration, indications and labelling may differ.