Imatinib
Indications
Imatinib is used for:
Chronic myeloid leukaemia, Acute lymphoblastic leukaemia, Myelodysplastic disease, Hypereosinophilic syndrome, Mastocytosis, Dermatofibrosarcoma protuberans, Malignant gastrointestinal stromal tumours
Adult Dose
Acute Lymphoblastic Leukemia
Indicated for adults with relapsed or refractory Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL)
600 mg PO qDay
Myelodysplastic/Myeloproliferative Diseases
Indicated in adults with myelodysplastic/ myeloproliferative diseases associated with platelet-derived growth factor receptor gene re-arrangements as determined with an FDA-approved test
400 mg PO qDay
Hypereosinophilic Syndrome/Eosinophilic Leukemia
Indicated for adults with hypereosinophilic syndrome and/or chronic eosinophilic leukemia who have the FIP1L1-PDGFR-alpha fusion kinase (mutational analysis or FISH demonstration of CHIC2 allele deletion) and for patients with HES and/or CEL who are FIP1L1-PDGFR-alpha fusion kinase negative or unknown
400 mg PO qDay
In patients with demonstrated F1P1L1-PDGFR-alpha fusion kinase: 100 mg PO qDay; may increase to 400 mg qDay in the absence of adverse drug reactions if assessments demonstrate an insufficient response to therapy
Chronic Myeloid Leukemia
Chronic phase
Newly diagnosed adult and pediatric patients with Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) in chronic phase
400 mg PO qDay
Chronic phase after failure of interferon-alpha therapy: May increase to 600 mg/day in the absence of severe adverse drug reaction and severe nonleukemia related neutropenia or thrombocytopenia in the following circumstances: disease progression (at any time), failure to achieve a satisfactory hematologic response after at least 3 months of treatment, failure to achieve a cytogenetic response after 6-12 months of treatment, or loss of a previously achieved hematologic or cytogenetic response
Accelerated phase or blast crisis
600 mg PO qDay
May increase to 400 mg PO q12hr in the absence of severe adverse drug reaction and severe nonleukemia related neutropenia or thrombocytopenia in the following circumstances: disease progression (at any time), failure to achieve a satisfactory hematologic response after at least 3 months of treatment, failure to achieve a cytogenetic response after 6-12 months of treatment, or loss of a previously achieved hematologic or cytogenetic response
Dermatofibrosarcoma Protuberans
Indicated for adults with unresectable, recurrent and/or metastatic dermatofibrosarcoma protuberans
400 mg PO q12hr
Mastocytosis
Indicated for adults with aggressive systemic mastocytosis without the D816V c-Kit mutation as determined with an FDA-approved test or with c-Kit mutational status unknown
Without D816V c-Kit mutation: 100 mg PO qDay
c-Kit mutational status unknown: 400 mg PO qDay if not responding to other therapies
ASM associated with eosinophilia (a clonal hematological disease related to the fusion kinase FIP1L1-PDGFR-alpha): 100 mg PO qDay initially, may increase to 400 mg/day in absence of adverse effects if response to therapy is insufficient
Gastrointestinal Stromal Tumors
Unresectable and/or metastatic malignant GIST
400 mg PO qDay; may increase to 400 mg BID in patients showing clear signs or symptoms of disease progression at a lower dose and in the absence of severe adverse drug reactions
Adjuvant treatment following complete gross resection of GIST
400 mg PO qDay x3 years
Hepatic impairment: Severe: Reduce dose by 25%.
Child Dose
Chronic Myeloid Leukemia
Indicated for newly diagnosed adult and pediatric patients with Philadelphia chromosome positive (Ph+) chronic myeloid leukemia (CML) in chronic phase
<1 year: Safety and efficacy not established
>1 year: 340 mg/m²/day PO; not to exceed 600 mg/day
Acute Lymphoblastic Leukemia
Indicated for treatment of newly diagnosed children with Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL)
<1 year: Safety and efficacy not established
>1 year: 340 mg/m²/day PO; not to exceed 600 mg/day
Renal Dose
Administration
Should be taken with food and large glass of water.
Contra Indications
Hypersensitivity. Lactation.
Precautions
Cardiac disease or increased risk for CHF. Monitor for signs of severe fluid retention. Monitor CBC regularly. Renal and hepatic impairment. Monitor LFTs. Pregnancy.
Lactation: Imatinib and its active metabolite are excreted into human milk; advise a lactating woman not to breastfeed during treatment and for 1 month after last dose
Pregnancy-Lactation
Pregnancy
Fetal harm when administered to a pregnant woman based on human and animal data
No clinical studies available regarding use in pregnant women
There have been postmarket reports of spontaneous abortions and congenital anomalies from women who have been exposed to imatinib during pregnancy
Test pregnancy status in females with reproductive potential before initiation of treatment
If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, apprise patient of potential risks to the fetus
Contraception
Females of reproductive potential: Advise to use effective contraception (methods that result in less than 1 % pregnancy rates) during treatment and for 14 days after discontinuing treatment
Lactation
Imatinib and its active metabolite are excreted into human milk
Advise a lactating woman not to breastfeed during treatment and for 1 month after last dose
Interactions
Increased serum levels w/ CYP3A4 inhibitors (e.g. azole antifungals, macrolide antibiotics). Reduced serum levels w/ CYP3A4 inducers (e.g. carbamazepine, dexamethasone, phenobarbital, phenytoin, rifampicin). May increase serum levels of substrates of CYP3A4 (e.g. ciclosporin, pimozide, triazolo-benzodiazepines, dihydropyridine Ca channel blockers, certain statins), CYP2C9 (e.g. warfarin) and CYP2D6.
Side Effects
Side effects of Imatinib :
>10%
Edema (53%), Neutropenia (Grade 3: 7-27%; Grade 4: 3-48%), Nausea (43%), Muscle cramps (35%), Musculoskeletal pain (34%), Thrombocytopenia (Grade 3: 1-31%; Grade 4: 1-34%), Rash (32%), Fatigue (31%), Diarrhea (30%), Headache (29%), Arthralgia (27%), Abd pain (23%), Myalgia (21%), Nasopharyngitis (19%), Hemorrhage (19%), Vomiting (15%), Dyspepsia (15%), Cough (13%), Dizziness (13%), URT infection (13%), Fever (12%), Weight gain (12%), Hepatotoxicity (6-12%), Insomnia (11%)
1-10%
Flushing, Palpitation, Dry skin, Erythema, Metabolic hyperglycemia, Stomatitis/mucositis, Lymphopenia
<1%
Aplastic anemia, Atrial fibrillation, Avascular necrosis, Cardiac failure, Cardiogenic shock, Embolism, Eosinophilia
Potentially Fatal: Hepatotoxicity, cerebral oedema, increased intracranial pressure, papilloedema. Severe fluid retention resulting in pleural and pericardial effusion, pulmonary oedema and ascites. Rarely, GI perforation.
Mode of Action
Imatinib, is a tyrosine kinase inhibitor that inhibits the BCR-ABL tyrosine kinase created by the Philadelphia chromosome abnormality in chronic myeloid leukaemia (CML). It blocks proliferation and induces apoptosis in BCR-ABL positive cell lines, as well as fresh leukaemic cells from Philadelphia chromosome positive CML. Imatinib also inhibits receptor kinases for platelet-derived growth factor (PDGF) and stem cell factor (SCF), c-kit, PDGF- and SCF-mediated cellular events.