Imatinib

Description

11 DESCRIPTION Imatinib is a small molecule kinase inhibitor. Imatinib mesylate film-coated tablets are supplied as 100 mg and 400 mg tablets for oral administration. Each 100 mg tablet contains 119.5 mg of imatinib mesylate equivalent to 100 mg of imatinib free base. Each 400 mg tablet contains 478 mg of imatinib mesylate equivalent to 400 mg of imatinib free base. Imatinib mesylate is designated chemically as 4-[(4-Methyl-1-piperazinyl)methyl]-N-[4-methyl-3-[[4-(3-pyridinyl)-2-pyrimidinyl]amino]-phenyl]benzamide methanesulfonate and its structural formula is: Imatinib mesylate is a white to off-white crystalline powder. Its molecular formula is C 29 H 31 N 7 O

What Is Imatinib Used For?

1 INDICATIONS AND USAGE Imatinib mesylate is a kinase inhibitor indicated for the treatment of:

Dosage and Administration

2 DOSAGE AND ADMINISTRATION Adults with Ph+ CML CP ( 2.2 ): 400 mg/day Adults with Ph+ CML AP or BC ( 2.2 ): 600 mg/day Pediatrics with Ph+ CML CP ( 2.3 ): 340 mg/m 2 /day Adults with Ph+ ALL ( 2.4 ): 600 mg/day Pediatrics with Ph+ ALL ( 2.5 ) 340 mg/m 2 /day Adults with MDS/MPD ( 2.6 ): 400 mg/day Adults with ASM ( 2.7 ): 100 mg/day or 400 mg/day Adults with HES/CEL ( 2.8 ): 100 mg/day or 400 mg/day Adults with DFSP ( 2.9 ): 800 mg/day Adults with metastatic and/or unresectable GIST ( 2.10 ): 400 mg/day Adjuvant treatment of adults with GIST ( 2.11 ): 400 mg/day Patients with mild to moderate hepatic impairment ( 2.12 ): 400 mg/day Patients with severe hepatic impairment ( 2.12 ): 300 mg/day All doses of imatinib mesylate tablets should be taken with a meal and a large glass of water. Doses of 400 mg or 600 mg (imatinib as free base) should be administered once daily, whereas a dose of 800 mg (imatinib as free base) should be administered as 400 mg (imatinib as free base) twice a day. Imatinib mesylate tablets can be dissolved in water or apple juice for patients having difficulty swallowing. Daily dosing of 800 mg (imatinib as free base) and above should be accomplished using the 400 mg tablet (imatinib as free base) to reduce exposure to iron. 2.1 Drug Administration The prescribed dose should be administered orally, with a meal and a large glass of water. Doses of 400 mg or 600 mg (imatinib as free base) should be administered once daily, whereas a dose of 800 mg (imatinib as free base) should be administered as 400 mg (imatinib as free base) twice a day. For patients unable to swallow the film-coated tablets, the tablets may be dispersed in a glass of water or apple juice. The required number of tablets should be placed in the appropriate volume of beverage (approximately 50 mL for a 100-mg tablet, and 200 mL for a 400-mg tablet) and stirred with a spoon. The suspension should be administered immediately after complete disintegration of the tablet(s). For daily dosing of 800 mg (imatinib as free base) and above, dosing should be accomplished using the 400-mg (imatinib as free base) tablet to reduce exposure to iron. Treatment may be continued as long as there is no evidence of progressive disease or unacceptable toxicity. 2.2 Adult Patients With Ph+ CML CP, AP, or BC The recommended dose of imatinib mesylate tablets is 400 mg/day (imatinib as free base) for adult patients in chronic phase CML and 600 mg/day (imatinib as free base) for adult patients in accelerated phase or blast crisis. In CML, a dose increase from 400 mg to 600 mg (imatinib as free base) in adult patients with chronic phase disease, or from 600 mg to 800 mg (imatinib as free base) (given as 400 mg twice daily) in adult patients in accelerated phase or blast crisis may be considered in the absence of severe adverse drug reaction and severe non-leukemia related neutropenia or thrombocytopenia in the following circumstances: disease progression (at any time), failure to...

Side Effects (Adverse Reactions)

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the labeling: Fluid Retention and Edema [see Warnings and Precautions ( 5.1 )] Hematologic Toxicity [see Warnings and Precautions ( 5.2 )] Congestive Heart Failure and Left Ventricular Dysfunction [see Warnings and Precautions ( 5.3 )] Hepatotoxicity [see Warnings and Precautions ( 5.4 )] Hemorrhage [see Warnings and Precautions ( 5.5 )] Gastrointestinal Disorders [see Warnings and Precautions ( 5.6 )] Hypereosinophilic Cardiac Toxicity [see Warnings and Precautions ( 5.7 )] Dermatologic Toxicities [see Warnings and Precautions ( 5.8 )] Hypothyroidism [see Warnings and Precautions ( 5.9 )] Growth Retardation in Children and Adolescents [see Warnings and Precautions ( 5.11 )] Tumor Lysis Syndrome [see Warnings and Precautions ( 5.12 )] Impairments Related to Driving and Using Machinery [see Warnings and Precautions ( 5.13 )] Renal Toxicity [see Warnings and Precautions ( 5.1 4 ) ] The most frequently reported adverse reactions (greater than or equal to 30%) were edema, nausea, vomiting, muscle cramps, musculoskeletal pain, diarrhea, rash, fatigue and abdominal pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Apotex Corp. at 1-800-706-5575 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. Chronic Myeloid Leukemia The majority of imatinib mesylate-treated patients experienced adverse reactions at some time. Imatinib was discontinued due to drug-related adverse reactions in 2.4% of patients receiving imatinib mesylate in the randomized trial of newly diagnosed patients with Ph+ CML in chronic phase comparing imatinib mesylate versus IFN+Ara-C, and in 12.5% of patients receiving imatinib mesylate in the randomized trial of newly diagnosed patients with Ph+ CML in chronic phase comparing imatinib mesylate and nilotinib. Imatinib mesylate was discontinued due to drug-related adverse reactions in 4% of patients in chronic phase after failure of interferon-alpha therapy, in 4% of patients in accelerated phase and in 5% of patients in blast crisis. The most frequently reported drug-related adverse reactions were edema, nausea and vomiting, muscle cramps, musculoskeletal pain, diarrhea and rash (Table 2 and Table 3 for newly diagnosed CML, Table 4 for other CML patients). Edema was most frequently periorbital or in lower limbs and was managed with diuretics, other supportive measures, or by reducing the dose of Imatinib [ see Dosage and Administration ( 2.13 ) ]. The frequency of severe superficial edema was 1.5% to 6%. A variety of adverse reactions represent local or general fluid retention, including pleural effusion, ascites, pulmonary edema, and rapid weight gain with or without superficial edema. These reactions appear to be dose related, were more common in the blast crisis and accelerated phase studies (where the dose was 600 mg/day), and are more common in the elderly. These reactions were usually managed by interrupting imatinib mesylate treatment and using diuretics or other appropriate supportive care measures. These reactions may be serious or life threatening. Adverse reactions, regardless of relationship to study drug, that were reported in at least 10% of the imatinib mesylate-treated patients are shown in Tables 2, 3, and 4. Table 2: Adverse Reactions Regardless of Relationship to Study Drug Reported in Newly Diagnosed CML Clinical Trial in the Imatinib Mesylate versus IFN+Ara-C Study (Greater Than or Equal to 10% of Imatinib Mesylate-Treated Patients) (1) All Grades CTC* Grades 3/4 Imatinib mesylate IFN+Ara−C Imatinib mesylate IFN+Ara−C Preferred term N = 551 (%) N = 533 (%) N = 551 (%) N = 533 (%) Fluid retention 61.7 11.1 2.5 0.9...

Drug Interactions

7 DRUG INTERACTIONS CYP3A4 inducers may decrease imatinib mesylate C max and area under curve (AUC). ( 2.12 , 7.1 , 12.3 ) CYP3A4 inhibitors may increase imatinib mesylate C max and AUC. ( 7.2 , 12.3 ) Imatinib mesylate is an inhibitor of CYP3A4 and CYP2D6 which may increase the C max and AUC of other drugs. ( 7.3 , 7.4 , 12.3 ) Patients who require anticoagulation should receive low-molecular weight or standard heparin and not warfarin. ( 7.3 ) Imatinib mesylate tablets delay the clearance of methotrexate when methotrexate is used at high doses (> 500 mg/m 2 ). ( 7.5 ) 7.1 Agents Inducing CYP3A Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inducers may reduce total exposure of imatinib; consider alternative agents [see Clinical Pharmacology ( 12.3 )] . 7.2 Agents Inhibiting CYP3A Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inhibitors may result in a significant imatinib exposure increase. Grapefruit juice may also increase plasma concentrations of imatinib; avoid grapefruit juice [see Clinical Pharmacology ( 12.3 )] . 7.3 Interactions With Drugs Metabolized by CYP3A4 Imatinib mesylate will increase plasma concentration of CYP3A4 metabolized drugs (e.g., triazolo-benzodiazepines, dihydropyridine calcium channel blockers, certain HMG-CoA reductase inhibitors, etc.). Use caution when administering imatinib mesylate tablets with CYP3A4 substrates that have a narrow therapeutic window. Because warfarin is metabolized by CYP2C9 and CYP3A4, use low-molecular weight or standard heparin instead of warfarin in patients who require anticoagulation [see Clinical Pharmacology ( 12.3 )] . 7.4 Interactions With Drugs Metabolized by CYP2D6 Use caution when administering imatinib mesylate with CYP2D6 substrates that have a narrow therapeutic window. 7.5 Interactions With Methotrexate Imatinib mesylate tablets delay the clearance of methotrexate and result in sustained methotrexate concentrations when methotrexate is used at high doses (>500 mg/m 2 ). Refer to the prescribing information for methotrexate injection for recommendations on management of methotrexate concentrations.

Contraindications

4 CONTRAINDICATIONS None. None ( 4 ).

Pregnancy and Breastfeeding

8.1 Pregnancy Risk Summary Imatinib mesylate tablets can cause fetal harm when administered to a pregnant woman based on human and animal data. There are no clinical studies regarding use of imatinib mesylate tablets in pregnant women. There have been postmarket reports of spontaneous abortions and congenital anomalies from women who have been exposed to imatinib mesylate tablets during pregnancy. Reproductive studies in rats have demonstrated that imatinib mesylate induced teratogenicity and increased incidence of congenital abnormalities following prenatal exposure to imatinib mesylate at doses equal to the highest recommended human dose of 800 mg/day based on BSA. Advise women to avoid pregnancy when taking imatinib mesylate tablets. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, apprise the patient of the potential hazard to the fetus. The background risk of major birth defects and miscarriage for the indicated population is not known; however, in the U.S. general population, the estimated background risk of major birth defects of clinically recognized pregnancies is 2% to 4% and of miscarriage is 15% to 20%. Data Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of imatinib mesylate up to 100 mg/kg/day and 60 mg/kg/day, respectively, during the period of organogenesis. In rats, imatinib mesylate was teratogenic at 100 mg/kg/day (approximately equal to the maximum human dose of 800 mg/day based on BSA), the number of fetuses with encephalocoele and exencephaly was higher than historical control values and these findings were associated with missing or underdeveloped cranial bones. Lower mean fetal body weights were associated with retarded skeletal ossifications. In rabbits, at doses 1.5 times higher than the maximum human dose of 800 mg/day based on BSA, no effects on the reproductive parameters with respect to implantation sites, number of live fetuses,...

8.2 Lactation Risk Summary Imatinib and its active metabolite are excreted into human milk. Because of the potential for serious adverse reactions in breastfed infants from imatinib mesylate, advise a lactating woman not to breastfeed during treatment and for 1 month after the last dose. Human Data Based on data from three breastfeeding women taking imatinib mesylate tablets, the milk: plasma ratio is about 0.5 for imatinib and about 0.9 for the active metabolite. Considering the combined concentration of imatinib and active metabolite, a breastfed infant could receive up to 10% of the maternal therapeutic dose based on body weight.

Overdosage

10 OVERDOSAGE Experience with doses greater than 800 mg is limited. Isolated cases of imatinib mesylate overdose have been reported. In the event of overdosage, observe the patient and give appropriate supportive treatment. Adult Overdose 1,200 to 1,600 mg (duration varying between 1 to 10 days) : Nausea, vomiting, diarrhea, rash erythema, edema, swelling, fatigue, muscle spasms, thrombocytopenia, pancytopenia, abdominal pain, headache, decreased appetite. 1,800 to 3,200 mg (as high as 3,200 mg daily for 6 days) : Weakness, myalgia, increased CPK, increased bilirubin, GI pain. 6,400 mg (single dose) : One case in the literature reported one patient who experienced nausea, vomiting, abdominal pain, pyrexia, facial swelling, neutrophil count decreased, increase transaminases. 8 to 10 g (single dose): Vomiting and GI pain have been reported. A patient with myeloid blast crisis experienced Grade 1 elevations of serum creatinine, Grade 2 ascites and elevated liver transaminase levels, and Grade 3 elevations of bilirubin after inadvertently taking 1,200 mg of imatinib mesylate (imatinib as free base) daily for 6 days. Therapy was temporarily interrupted and complete reversal of all abnormalities occurred within 1 week. Treatment was resumed at a dose of 400 mg daily (imatinib as free base) without recurrence of adverse reactions. Another patient developed severe muscle cramps after taking 1,600 mg of imatinib mesylate (imatinib as free base) daily for 6 days. Complete resolution of muscle cramps occurred following interruption of therapy and treatment was subsequently resumed. Another patient that was prescribed 400 mg daily (imatinib as free base), took 800 mg of imatinib mesylate (imatinib as free base) on Day 1 and 1,200 mg (imatinib as free base) on Day 2. Therapy was interrupted, no adverse reactions occurred and the patient resumed therapy. Pediatric Overdose One 3 year old male exposed to a single dose of 400 mg experienced vomiting, diarrhea, and anorexia and...

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING Each imatinib mesylate film-coated tablet contains 100 mg or 400 mg of imatinib free base. 100 mg Tablets Brownish orange, slightly biconvex, round film-coated tablets with functional scoring, engraved "IMA" over score "100" on one side, "APO" on the other side Bottles of 30 tablets………………………...…………NDC 60505-2900-3 Bottles of 90 tablets…………………………………...NDC 60505-2900-9 Bottles of 100 tablets………………………………….NDC 60505-2900-1 Bottles of 1,000 tablets………………………………...NDC 60505-2900-8 Blisters of 100 tablets (10 x 10)………………….…....NDC 60505-2900-0 400 mg Tablets Brownish orange, capsule shaped, biconvex film-coated tablets with functional scoring, engraved "IMA" score "400" on one side, "APO" on the other side Bottles of 30 tablets………………………………..…..NDC 60505-2901-3 Bottles of 90 tablets…………………………………....NDC 60505-2901-9 Bottles of 100 tablets…………………………………..NDC 60505-2901-1 Bottles of 500 tablets…………………………………..NDC 60505-2901-5 Blisters of 100 tablets (10 x 10)…………….……….....NDC 60505-2901-0 Storage and Handling Store at 20ºC to 25ºC (68ºF to 77ºF); excursions permitted from 15°C to 30ºC (59°F to 86ºF) [see USP Controlled Room Temperature]. Protect from moisture. Dispense in a tight container, USP. Do not crush imatinib mesylate tablets. Avoid direct contact of crushed tablets with the skin or mucous membranes. If such contact occurs, wash thoroughly as outlined in the references. Avoid exposure to crushed tablets.