Iwilfin

Pronunciation: I-WILL-fin
Generic name: eflornithine
Dosage form: oral tablet
Drug class: Miscellaneous antineoplastics

Medically reviewed by Carmen Pope, BPharm. Last updated on Dec 20, 2023.

What is Iwilfin?

Iwilfin (eflornithine) is an oral ornithine decarboxylase inhibitor used to reduce the risk of relapse in adults and children with high-risk neuroblastoma (HRNB) who have demonstrated at least a partial response to prior treatment with other agents including anti-GD2 immunotherapy.

Iwilfin works as an irreversible inhibitor of the enzyme ornithine decarboxylase which is an enzyme that plays a critical role in the synthesis of polyamines which are nitrogenous bases that are involved in cell growth and proliferation, including the transformation of normal cells into cancerous cells. Iwilfin also targets the MYCN gene which is an oncogene. When mutated, oncogenes have the potential to cause normal cells to become cancerous. By inhibiting these processes suppresses neuroblastoma tumor growth and formation.

High-risk neuroblastoma is a highly aggressive solid cancerous tumor that most commonly begins in the nerve cells outside the brain (most commonly the adrenal glands located on the top of both kidneys) of infants and children younger than 5. It can sometimes be found during a prenatal (before birth) ultrasound, and more rarely, can develop in older children and young adults.

Eflornithine was first approved under the brand name Ornidyl (eflornithine hydrochloride) in 1990 in injection form for the treatment of African trypanosomiasis (sleeping sickness). A topical cream formulation of eflornithine was approved under the brand name Vaniqa (eflornithine hydrochloride) in 2000 for the treatment of hirsutism (unwanted facial hair) in women. Both Ornidyl and Vaniqa are now discontinued in the United States.

Iwilfin was FDA-approved on the 13th of December 2023.

Warnings

Iwilfin may cause bone marrow suppression and liver toxicity. Your healthcare provider will monitor your blood counts and liver function tests before and during treatment and may modify treatment based on severity.

Iwilfin can cause hearing loss. Your healthcare provider will monitor your hearing before and during treatment with Iwilfin and may modify treatment depending on the presence of hearing loss.

Can cause fetal harm. If you are a woman of childbearing potential you will need to use effective contraception before and during Iwilfin treatment.

Before taking

Before taking Iwilfin, tell your healthcare provider about all of your medical conditions, including if you:

have hearing problems
are pregnant or plan to become pregnant
are breastfeeding or plan to breastfeed.

Before starting Iwilfin, your healthcare provider will perform a baseline hearing assessment, complete blood count, and liver function tests.

Pregnancy and breastfeeding

Iwilfin can harm an unborn baby. Tell your healthcare provider right away if you become pregnant during treatment with Iwilfin or think you may be pregnant.

Females who can become pregnant should have a pregnancy test before starting treatment with Iwilfin and use effective birth control during treatment and for 1 week after the last dose.

Males with female partners who can become pregnant should use effective birth control during treatment with Iwilfin and for 1 week after the last dose.

It is not known if Iwilfin passes into your breast milk. Do not breastfeed during treatment with and for 1 week after the last dose.

How should I take Iwilfin?

Take it exactly as your healthcare provider tells you to take it. The recommended dosage is based on body surface area. Your healthcare provider will calculate this for you.

Take Iwilfin 2 times a day with or without food.
Swallow the tablets whole. If you cannot swallow tablets whole, you can chew or crush the tablets and then mix them with 2 tablespoons of soft food or liquid. If you are crushing Iwilfin tablets:
Eat the entire mixture.
- If any crushed tablet pieces remain, mix with another small amount (about 2 tablespoons) of soft food or liquid.
- Take all of the mixture within 1 hour of mixing. Throw away any mixture left after 1 hour.

Iwilfin is taken until disease progression or unacceptable toxicity occurs, or for a maximum of two years.

What happens if I miss a dose?

If you miss a dose of Iwilfin, take it as soon as you remember. If it is within 7 hours of your next scheduled dose, skip the missed dose and take your next dose at your regular time.

If you vomit after taking a dose, do not take an extra dose. Take your next dose at your regular time.

What happens if I overdose?

Ring your healthcare provider immediately or go to the emergency department.

What are the side effects of Iwilfin?

Iwilfin may cause serious side effects, including:

Low blood cell counts and failure of your bone marrow to make enough platelets, red blood cells, or white blood cells. Your healthcare provider will monitor your blood cell counts before starting and during treatment. Tell your healthcare provider right away if you develop symptoms of low blood cell counts, including:
- fever (temperature 100.4°F or higher)
- feeling unusually tired or weak
- easy bruising or bleeding
- shortness of breath
- blood in your urine or stools
- chills or shivering.
Liver problems. Your healthcare provider will do blood tests before starting, every month for the first 6 months, and regularly during treatment with Iwilfin to check your liver. Tell your healthcare provider if you develop symptoms of liver problems, including:
- your skin or the white part of your eyes turns yellow (jaundice)
- nausea or vomiting
- easy bruising or bleeding
- dark or “tea-colored” urine
- loss of appetite
- light-colored stools (bowel movements)
- pain, aching, or tenderness on the right side of your stomach area (abdomen).
New or worsening hearing loss. Hearing loss is common during treatment with Iwilfin and can also be serious. Your healthcare provider will check your hearing before you start and during treatment with Iwilfin. Some people have needed to use hearing aids. Tell your healthcare provider right away if you get ringing in your ears or any new or worsening hearing loss.

The most common side effects of Iwilfin affecting 5% or more people include:

hearing loss
ear infections
fever
pneumonia
diarrhea
laboratory abnormalities.

Other less common side effects may include:

red and swollen eyes (pink eye)
vomiting
cough
stuffy, runny, itchy nose or sneezing (allergic rhinitis)
sinus infections
skin infections
upper respiratory tract infections
urinary tract infections.

These are not all the possible side effects of Iwilfin. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

What other drugs will affect Iwilfin?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Storage

Store at room temperature between 68°F to 77°F (20°C to 25°C).

Keep Iwilfin and all medicines out of the reach of children.

Ingredients

Active: eflornithine.

Inactive: silicified microcrystalline cellulose, partially pregelatinized maize starch, colloidal silicon dioxide, and vegetable source magnesium stearate.

Available as 192mg tablets for oral use.