Idhifa for Acute Myeloid Leukemia (AML): Side Effects & Dosage

Generic drug: enasidenib

Brand name: Idhifa

What is Idhifa (enasidenib), and how does it work?

Idhifa (enasidenib) is a prescription medicine used to treat people with acute myeloid leukemia (AML) with an isocitrate dehydrogenase-2 (IDH2) mutation whose disease has come back or has not improved after previous treatment(s). It is not known if Idhifa is safe and effective in children.

What are the side effects of Idhifa?

WARNING

DIFFERENTIATION SYNDROME

Patients treated with Idhifa have experienced symptoms of differentiation
syndrome, which can be fatal if not treated. Symptoms may include fever,
dyspnea, acute respiratory distress, pulmonary infiltrates, pleural or
pericardial effusions, rapid weight gain or peripheral edema, lymphadenopathy,
bone pain, and hepatic, renal, or multi-organ dysfunction. If differentiation
syndrome is suspected, initiate corticosteroid therapy and hemodynamic
monitoring until symptom resolution.

Idhifa may cause serious side effects, including:

The most common side effects of
Idhifa include:

Tell your healthcare provider if you have any changes to the color of your skin or the whites of your eyes.

Your healthcare provider will monitor you for side effects during treatment and may tell you to stop taking
Idhifa if you develop certain side effects.

These are not all the possible side effects of
Idhifa.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What is the dosage for Idhifa?

Patient Selection

Select patients for the treatment of AML with
Idhifa based on the presence of IDH2 mutations in the blood or bone marrow. Information on FDA-approved tests for the detection of IDH2 mutations in AML is available at http://www.fda.gov/CompanionDiagnostics.

Recommended Dosage

The recommended dosage of Idhifa is 100 mg taken orally once daily with or without food until disease progression or unacceptable toxicity. For patients without disease progression or unacceptable toxicity, treat for a minimum of 6 months to allow time for clinical response.
Do not split or crush Idhifa tablets. Administer Idhifa tablets orally about the same time each day. If a dose of
Idhifa is vomited, missed, or not taken at the usual time, administer the dose as soon as possible on the same day, and return to the normal schedule the following day.

Monitoring And Dosage Modifications For Toxicities

Assess blood counts and blood chemistries for leukocytosis and tumor lysis
syndrome prior to the initiation of Idhifa and monitor at a minimum of every 2
weeks for at least the first 3 months during treatment. Manage any abnormalities
promptly.

Interrupt dosing or reduce dose for toxicities. See Table 1 for dosage modification guidelines.

Table 1: Dosage Modifications for
Idhifa-Related Toxicities

Adverse ReactionRecommended Action

Differentiation syndrome

If differentiation syndrome is suspected, administer systemic
corticosteroids and initiate hemodynamic monitoring.
Interrupt
Idhifa if severe pulmonary symptoms requiring intubation or ventilator
support, and/or renal dysfunction persist for more than 48 hours after
initiation of corticosteroids.
Resume Idhifa when signs and symptoms improve to Grade 2* or lower.

Noninfectious leukocytosis (white blood cell [WBC] count greater than 30 x 10⁹/L)

Initiate treatment with hydroxyurea, as per standard institutional practices.
Interrupt
Idhifa if leukocytosis is not improved with hydroxyurea, and then resume
Idhifa at 100 mg daily when WBC is less than 30 x 10⁹/L.

Elevation of bilirubin greater than 3 times the upper limit of normal (ULN) sustained for ≥2 weeks without elevated transaminases or other hepatic disorders

Reduce
Idhifa dose to 50 mg daily.
Resume Idhifa at 100 mg daily if bilirubin elevation resolves to less than 2 x ULN.

Other Grade 3* or higher toxicity considered related to treatment including tumor lysis syndrome

Interrupt
Idhifa until toxicity resolves to Grade 2* or lower.
Resume
Idhifa at 50 mg daily; may increase to 100 mg daily if toxicities resolve to Grade 1* or lower.
If Grade 3* or higher toxicity recurs, discontinue
Idhifa.

*Grade 1 is mild, Grade 2 is moderate, Grade 3 is serious, Grade 4 is life-threatening.

What drugs interact with Idhifa?

Effect Of Idhifa On Other Drugs

OATP1B1, OATP1B3, And BCRP Substrates

Idhifa is an OATP1B1, OATP1B3, and BCRP inhibitor. Coadministration of
Idhifa
increases the exposure of OATP1B1, OATP1B3, and BCRP substrates, which may
increase the incidence and severity of adverse reactions of these substrates.
Decrease the dosage of OATP1B1, OATP1B3, and BCRP substrate(s) as recommended in the respective prescribing information, and as clinically indicated.

Certain P-glycoprotein (P-gp) Substrates

Idhifa is a P-gp inhibitor. Coadministration of Idhifa increases the exposure of
P-gp substrates, which may increase the incidence and severity of adverse
reactions of these substrates.
For a P-gp substrate where small concentration changes may lead to serious adverse reactions, decrease the dose or modify the dosing frequency of such a P-gp substrate and monitor for adverse reactions as recommended in the respective prescribing information.

Is Idhifa safe to use while pregnant or breastfeeding?

Based on animal embryo-fetal toxicity studies, Idhifa can cause fetal harm when administered to a pregnant woman.
There are no available data on Idhifa use in pregnant women to inform a drug-associated risk of major birth defects and miscarriage.
There are no data on the presence of enasidenib or its metabolites in human milk, the effects on the breastfed child, or the effects on milk production.
Because of the potential for adverse reactions in the breastfed child, advise women not to breastfeed during treatment with
Idhifa and for at least 2 months after the last dose.