IDHIFA

Enasidenib is an inhibitor of isocitrate dehydrogenase-2 (IDH2) enzyme. Enasidenib is available as the mesylate salt with the chemical name: 2-methyl-1-[(4-[6-(trifluoromethyl)pyridin-2-yl]-6-{[2-(trifluoromethyl)pyridin-4-yl]amino}-1,3,5-triazin-2-yl)amino]propan-2-ol methanesulfonate. Or 2-Propanol, 2-methyl-1-[[4-[6-(trifluoromethyl)-2-pyridinyl]-6-[[2-(trifluoromethyl)-4-pyridinyl]amino-1,3,5-triazin-2-yl]amino]-, methanesulfonate (1:1). The chemical structure is: The empirical formula is C 19 H 17 F 6 N 7 O ∙ CH 3 SO 3 H (C 20 H 21 F 6 N 7 O 4 S), and the molecular weight is 569.48 g/mol. Enasidenib is practically insoluble (solubility ≤74 mcg/mL) in aqueous solutions across physiological pH range (pH 1.2 and 7.4). IDHIFA (enasidenib) is available as a 50 mg tablet (equivalent to 60 mg enasidenib mesylate) and a 100 mg tablet (equivalent to 120 mg enasidenib mesylate) for oral administration. Each tablet contains inactive ingredients of colloidal silicon dioxide, hydroxypropyl cellulose, hypromellose acetate succinate, iron oxide yellow, magnesium stearate, microcrystalline cellulose, polyethylene glycol, polyvinyl alcohol, sodium lauryl sulfate, sodium starch glycolate, talc, and titanium dioxide. Chemical Structure

IDHIFA is an isocitrate dehydrogenase-2 inhibitor indicated for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with an isocitrate dehydrogenase-2 (IDH2) mutation as detected by an FDA-approved test ( 1.1 ). 1.1 Acute Myeloid Leukemia IDHIFA is indicated for the treatment of adult patients with relapsed or refractory acute myeloid leukemia (AML) with an isocitrate dehydrogenase-2 (IDH2) mutation as detected by an FDA-approved test.

100 mg orally once daily until disease progression or unacceptable toxicity ( 2.2 ). 2.1 Patient Selection Select patients for the treatment of AML with IDHIFA based on the presence of IDH2 mutations in the blood or bone marrow [see Indications and Usage (1.1) and Clinical Studies (14.1) ] . Information on FDA-approved tests for the detection of IDH2 mutations in AML is available at http://www.fda.gov/CompanionDiagnostics . 2.2 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. Swallow tablets whole. Do not chew, 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. 2.3 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 [see Adverse Reactions (6.1) ] . Interrupt dosing or reduce dose for toxicities. See Table 1 for dosage modification guidelines. Table 1: Dosage Modifications for IDHIFA-Related Toxicities *Grade 1 is mild, Grade 2 is moderate, Grade 3 is serious, Grade 4 is life-threatening. Adverse Reaction Recommended Action • Differentiation syndrome • If differentiation syndrome is suspected, administer systemic corticosteroids and initiate hemodynamic monitoring [see Warnings and Precautions (5.1) ] . • 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 [see Warnings and Precautions (5.1) ] . • Resume IDHIFA when signs and symptoms improve to Grade 2* or lower. • Noninfectious leukocytosis (white blood cell [WBC] count greater than 30 × 10 9 /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 × 10 9 /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 × 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.

None. None ( 4 ).

The following clinically significant adverse reactions are described elsewhere in the labeling: • Differentiation Syndrome [see Warnings and Precautions (5.1) ] The most common adverse reactions (≥20%) are nausea, vomiting, diarrhea, elevated bilirubin, and decreased appetite ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Bristol Myers Squibb at 1-800-721-5072 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety evaluation of single-agent IDHIFA is based on 214 patients with relapsed or refractory AML who were assigned to receive 100 mg daily [see Clinical Studies (14.1) ] . The median duration of exposure to IDHIFA was 4.3 months (range 0.3 to 23.6). The 30-day and 60-day mortality rates observed with IDHIFA were 4.2% (9/214) and 11.7% (25/214), respectively. Serious adverse reactions were reported in 77.1% of patients. The most frequent serious adverse reactions (≥2%) were leukocytosis (10%), diarrhea (6%), nausea (5%), vomiting (3%), decreased appetite (3%), tumor lysis syndrome (5%), and differentiation syndrome (8%). Differentiation syndrome events characterized as serious included pyrexia, renal failure acute, hypoxia, respiratory failure, and multi-organ failure. Overall, 92 of 214 patients (43%) required a dose interruption due to an adverse reaction; the most frequent adverse reactions leading to dose interruption were differentiation syndrome (4%) and leukocytosis (3%). Ten of 214 patients (5%) required a dose reduction due to an adverse reaction; no adverse reaction required dose reduction in more than 2 patients. Thirty-six of 214 patients (17%) permanently discontinued IDHIFA due to an adverse reaction; the most frequent adverse reaction leading to permanent discontinuation was leukocytosis (1%). The most common adverse reactions (≥20%) of any grade were nausea, vomiting, diarrhea, elevated bilirubin and decreased appetite. Adverse reactions reported in the trial are shown in Table 2. Table 2: Adverse Reactions Reported in ≥10% (Any Grade) or ≥3% (Grade 3-5) of Patients with Relapsed or Refractory AML a Gastrointestinal disorders observed with IDHIFA treatment can be associated with other commonly reported events such as abdominal pain, and weight decreased. b Tumor lysis syndrome observed with IDHIFA treatment can be associated with commonly reported uric acid increased. c Differentiation syndrome can be associated with other commonly reported events such as respiratory failure, dyspnea, hypoxia, pyrexia, peripheral edema, rash, or renal insufficiency. IDHIFA (100 mg daily) N=214 Body System Adverse Reaction All Grades N=214 n (%) ≥Grade 3 N=214 n (%) Gastrointestinal Disorders a Nausea 107 (50) 11 (5) Diarrhea 91 (43) 17 (8) Vomiting 73 (34) 4 (2) Metabolism and Nutrition Disorders Decreased appetite 73 (34) 9 (4) Tumor lysis syndrome b 13 (6) 12 (6) Blood and Lymphatic System Disorders Differentiation syndrome c 29 (14) 15 (7) Noninfectious leukocytosis 26 (12) 12 (6) Nervous System Disorders Dysgeusia 25 (12) 0 (0) Other clinically significant adverse reactions occurring in <10% of patients included: • Respiratory, Thoracic, and Mediastinal Disorders: Pulmonary edema, acute respiratory distress syndrome Changes in selected post-baseline laboratory values that were observed in patients with relapsed or refractory AML are shown in Table 3. Table 3: Most Common (≥20%) New or Worsening Laboratory Abnormalities Reported in Patients with Relapsed or Refractory AML IDHIFA (100 mg daily) N=214 Parameter a All Grades (%) Grade ≥3 (%) a Includes abnormalities occurring up to 28 days after last IDHIFA dose, if new or worsened by at least one grade from baseline, or if baseline was unknown. The denominator varies based on data collected for each parameter (N=213 except phosphorous N=209). Total bilirubin increased 81 15 Calcium decreased 74 8 Potassium decreased 41 15 Phosphorus decreased 27 8 Elevated Bilirubin IDHIFA may interfere with bilirubin metabolism through inhibition of UGT1A1 [see Clinical Pharmacology (12.3) ] . Thirty-seven percent of patients (80/214) experienced total bilirubin elevations ≥2 x ULN at least one time. Of those patients who experienced total bilirubin elevations ≥2 x ULN, 35% had elevations within the first month of treatment, and 89% had no concomitant elevation of transaminases or other severe adverse events related to liver disorders. No patients required a dose reduction for hyperbilirubinemia; treatment was interrupted in 3.7% of patients, for a median of 6 days. Three patients (1.4%) discontinued IDHIFA permanently due to hyperbilirubinemia. Noninfectious Leukocytosis IDHIFA can induce myeloid proliferation resulting in a rapid increase in white blood cell count. Tumor Lysis Syndrome IDHIFA can induce myeloid proliferation resulting in a rapid reduction in tumor cells which may pose a risk for tumor lysis syndrome. Other Clinical Trials Experience The following adverse reactions occurred in other clinical trials of IDHIFA at the recommended dosage: neutropenia, thrombocytopenia, anemia, stomatitis, renal failure, fatigue, dyspnea, and QT prolongation.

• Certain CYP1A2 and CYP2C19 Substrates: Avoid concomitant use unless otherwise recommended in the Prescribing Information ( 7.1 ). • Certain CYP3A Substrates: Avoid concomitant use unless otherwise recommended in the Prescribing Information ( 7.1 ). • Certain OATP1B1, OATP1B3, and BCRP Substrates: Avoid concomitant use unless otherwise recommended in the Prescribing Information ( 7.1 ). 7.1 Effect of IDHIFA on Other Drugs Certain CYP1A2 Substrates Avoid concomitant use with IDHIFA unless otherwise recommended in the Prescribing Information for CYP1A2 substrates where minimal concentration changes may lead to serious adverse reactions. Consider reducing the frequency of caffeine intake from various food and beverages in a 24 hour period while taking IDHIFA because IDHIFA may increase the effect of caffeine in patients who are sensitive to it. Enasidenib is a CYP1A2 inhibitor. Concomitant use of IDHIFA increases the exposure of CYP1A2 substrates [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions related to the substrates. Certain CYP2C19 substrates Avoid concomitant use with IDHIFA unless otherwise recommended in the Prescribing Information for CYP2C19 substrates where minimal concentration changes may lead to serious adverse reactions. Enasidenib is a CYP2C19 inhibitor. Concomitant use of IDHIFA increases the exposure of CYP2C19 substrates [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions related to these substrates. Certain CYP3A substrates Avoid concomitant use with IDHIFA unless otherwise recommended in the Prescribing Information for CYP3A substrates where minimal concentration changes may lead to reduced efficacy. Do not administer IDHIFA with anti-fungal agents that are substrates of CYP3A due to expected loss of antifungal efficacy. Co-administration of IDHIFA may decrease the concentrations of hormonal contraceptives. Consider alternative methods of contraception in patients receiving IDHIFA [See use in Specific Population (8.1 , 8.3 )] . Enasidenib is a CYP3A inducer. Concomitant use of IDHIFA decreases the exposure of CYP3A substrates [see Clinical Pharmacology (12.3) ] , which may reduce the efficacy of the substrates. Certain OATP1B1, OATP1B3, and BCRP Substrates Avoid coadministration of IDHIFA with OATP1B1, OATP1B3, and BCRP substrates, for which minimal concentration changes may lead to serious toxicities. If coadministration cannot be avoided, decrease the OATP1B1, OATP1B3, and BCRP substrates dosage(s) in accordance with the respective Prescribing Information. Enasidenib is an OATP1B1, OATP1B3, and BCRP transporter inhibitor. Concomitant use of IDHIFA increases the exposure of OATP1B1, OATP1B3, and BCRP substrates [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions related to these substrates. Certain P-glycoprotein (P-gp) Substrates When coadministered with IDHIFA, follow recommended P-gp substrates Prescribing Information and monitor more frequently for adverse reactions related to these substrates. Enasidenib is a P-gp transporter inhibitor. Concomitant use of IDHIFA increases the exposure of P-gp substrates [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions related to the substrates.