General

High Alert Medication: This medication bears a heightened risk of causing significant patient harm when it is used in error.

Genetic Implications:

Pronunciation:
eye-voe-sid-e-nib

Trade Name(s)

• Tibsovo

Ther. Class.

antineoplastics

Pharm. Class.

isocitrate dehydrogenase-1 inhibitor

Indications

•   Newly diagnosed acute myeloid leukemia (AML) with a susceptible isocitrate dehydrogenase-1 (IDH1) mutation in patients who are ≥75 years old or who have comorbidities that prevent the use of intensive induction chemotherapy (as monotherapy or in combination with azacitidine).
•   Relapsed or refractory AML with a susceptible IDH1 mutation.
•   Relapsed or refractory myelodysplastic syndromes with a susceptible IDH1 mutation.
•   Previously treated, locally advanced, or metastatic cholangiocarcinoma with an IDH1 mutation

Action

Inhibits the mutant IDH1 enzyme. Susceptible IDH1 mutations can lead to ↑ levels of 2-hydroxyglutarate (2-HG) in leukemia cells, which can ultimately lead to impaired hematopoietic differentiation.

Therapeutic Effect(s):

• Induction of complete remission or complete remission with partial hematologic recovery in AML.
• Induction of complete remission in myelodysplastic syndromes.
• Improved progression-free survival in cholangiocarcinoma.

Pharmacokinetics

Absorption: Rapidly absorbed; absorption ↑ by high-fat meals.

Distribution: Extensively distributed to tissues.

Protein Binding: 92–96%.

Metabolism and Excretion: Primarily metabolized in the liver by the CYP3A4 isoenzyme. Primarily excreted in feces (77%; 67% as unchanged drug); 17% excreted in urine (10% as unchanged drug).

Half-life: 93 hr.

TIME/ACTION PROFILE (plasma concentrations)

Contraindication/Precautions

Contraindicated in:

• OB:   Pregnancy;
• Lactation:  Lactation.

Use Cautiously in:

• Congenital long QT syndrome, HF, electrolyte abnormalities, or concurrent use of QT interval prolonging medications (↑ risk of QT interval prolongation);
• Severe renal impairment;
• Severe hepatic impairment;
• Pedi:   Safety and effectiveness not established in children.

Adverse Reactions/Side Effects

CV: chest pain, hypotension, peripheral edema, QT interval prolongation

Derm: pruritus, rash

Endo: hyperuricemia

F and E: hypocalcemia, hypokalemia, hypomagnesemia, hyponatremia, hypophosphatemia

GI: ↑ liver enzymes, abdominal pain, constipation, diarrhea, dyspepsia, hyperbilirubinemia, mucositis, nausea, vomiting

GU: ↑ serum creatinine

Hemat: anemia, differentiation syndrome, leukocytosis

Metabolic: ↓ appetite, ↓ weight

MS: arthralgia, myalgia

Neuro: neuropathy, dizziness, fatigue, headache, Guillain-Barré syndrome

Resp: cough, dyspnea, pleural effusion

Misc: fever, tumor lysis syndrome

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Drug-Drug

•  QT interval prolonging drugs  may ↑ risk of QT interval prolongation; avoid concurrent use.
•  Moderate or strong CYP3A4 inhibitors, including  fluconazole  and  itraconazole, may ↑ levels and risk of toxicity; avoid concurrent use, if possible; if concurrent use unavoidable, ↓ ivosidenib dose.
•  Strong CYP3A4 inducers, including  rifampin, may ↓ levels and effectiveness; avoid concurrent use.
• May ↓ levels and effectiveness of  CYP3A4 substrates, including  itraconazole,  ketoconazole, or  hormonal contraceptives ; avoid concurrent use.
• May ↓ levels and effectiveness of  CYP2C9 substrates, including  itraconazole ; avoid concurrent use.

Route/Dosage

Acute Myeloid Leukemia or Myelodysplastic Syndromes

PO (Adults): 500 mg once daily until disease progression or unacceptable toxicity. In absence of disease progression or unacceptable toxicity, continue therapy for ≥6 mo.  Concurrent use of strong CYP3A4 inhibitor: 250 mg once daily until disease progression or unacceptable toxicity. In absence of disease progression or unacceptable toxicity, continue therapy for ≥6 mo.

Cholangiocarcinoma

PO (Adults): 500 mg once daily until disease progression or unacceptable toxicity.  Concurrent use of strong CYP3A4 inhibitor: 250 mg once daily until disease progression or unacceptable toxicity.

Availability

Tablets: 250 mg

Assessment

• Monitor ECG at least weekly for 1st 3 wk of therapy and then at least monthly during therapy.  If QTc interval >480–500 msec,  monitor and supplement electrolyte levels as needed; hold ivosidenib and resume at 500 mg once daily after QTc interval <480 msec. Monitor ECGs at least weekly for 2 wk following resolution of QTc interval prolongation.  If QT interval >500 msec,  monitor and supplement electrolyte levels as needed; hold ivosidenib and resume at 250 mg once daily after QTc interval returns to within 30 msec of baseline or ≤480 msec. Monitor ECG at least weekly for 2 wk following resolution. Consider re-escalating dose to 500 mg once daily if a cause for QTc interval prolongation identified.  If QTc interval prolongation with signs and symptoms of life-threatening arrhythmia occurs,  permanently discontinue ivosidenib.
• Monitor for signs and symptoms of differentiation syndrome (noninfectious leukocytosis, peripheral edema, rapid weight gain, pyrexia, dyspnea, pleural effusion, hypotension, hypoxia, pulmonary edema, pneumonitis, pericardial effusion, rash, fluid overload, tumor lysis syndrome, renal impairment, hepatic impairment) during therapy.  If differentiation syndrome suspected, administer systemic corticosteroids (dexamethasone 10 mg IV every 12 hr or equivalent) and begin hemodynamic monitoring until symptom resolution and for ≥3 days.  If severe signs/symptoms persist >48 hr after starting corticosteroids,  hold ivosidenib . Resume therapy when signs and symptoms Grade ≤2.
• Monitor for onset of new signs or symptoms of motor and/or sensory neuropathy (unilateral or bilateral weakness, sensory alterations, paresthesias, difficulty breathing). May cause Guillain-Barré syndrome.  If diagnosis is confirmed,  permanently discontinue ivosidenib.

Lab Test Considerations:

 Patient selection is based on presence of IDH1 mutations. Information on FDA-approved tests for the detection of IDH1 mutations in AML is available at https://www.fda.gov/CompanionDiagnostics.

• Assess CBC and blood chemistries before starting therapy, at least weekly for 1st mo, once every other week for 2nd mo, and monthly during therapy.
• Monitor CK weekly for 1st mo of therapy.
• If noninfectious leukocytosis (WBC >25 × 10⁹ /L or absolute ↑ in total WBC >15 × 10⁹ /L from baseline) occurs,  treat with hydroxyurea and leukapheresis, if indicated. Taper hydroxyurea only after leukocytosis improves or resolves. If leukocytosis not improved with hydroxyurea, hold ivosidenib and resume at 500 mg once daily when leukocytosis resolved.

Implementation

• PO Administer once daily, at same time each day, without regard to food. Avoid taking with high-fat meals.  DNC: Swallow tablets whole; do not crush, break, or chew. 

Patient/Family Teaching

• Instruct patient to take ivosidenib as directed. Avoid taking with high-fat meals. If vomiting occurs after taking dose, omit dose and take next dose when scheduled. Take missed doses as soon as remembered ≥12 hr from next dose; do not take two doses within 12 hr. Advise patient to read  Medication Guide  before starting therapy and with each Rx refill in case of changes.
• Advise patient to notify health care provider immediately if signs/symptoms of differentiation syndrome (fever, cough, low BP, rapid weight gain, trouble breathing, swelling of arms or legs, rash, ↓ urination) occur.
• Advise patient to notify health care provider immediately if signs and symptoms of QT interval prolongation (dizziness, light-headedness, feeling faint) or Guillain-Barré syndrome (weakness or tingling feeling in legs, arms, or upper body; numbness and pain on one or both sides of body; changes in ability to see, touch, hear, or taste; burning or prickling sensation; difficulty breathing) occur.
• Instruct patient to notify health care provider of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care provider before taking other medications.
• Rep:  May cause fetal harm. Advise women of reproductive potential to use effective nonhormonal contraception during therapy and to avoid breastfeeding during and for ≥1 mo after last dose. May ↓ fertility in men and women.

Evaluation/Desired Outcomes

• Induction of complete remission or complete remission with partial hematologic recovery in AML.
• Induction of complete remission in myelodysplastic syndromes.
• Improved progression-free survival in cholangiocarcinoma.