Clinically relevant interactions
Dasatinib is a substrate and an inhibitor of cytochrome P450 (CYP) 3A4. Therefore, there is a potential for interaction with other concomitantly administered medicinal products that are metabolized primarily by or modulate the activity of CYP3A4 (see section 4.5).
Concomitant use of dasatinib and medicinal products that potently inhibit CYP3A4 (e.g. ketoconazole, itraconazole, erythromycin, clarithromycin, ritonavir, telithromycin) may increase exposure to dasatinib. Therefore, in patients receiving dasatinib, coadministration of a potent CYP3A4 inhibitor is not recommended (see section 4.5).
Concomitant use of dasatinib and medicinal products that induce CYP3A4 (e.g. dexamethasone, phenytoin, carbamazepine, rifampicin, phenobarbital or herbal preparations containing Hypericum perforatum, also known as St. John's Wort) may substantially reduce exposure to dasatinib, potentially increasing the risk of therapeutic failure. Therefore, in patients receiving dasatinib, coadministration of alternative medicinal products with less potential for CYP3A4 induction should be selected (see section 4.5).
Concomitant use of dasatinib and a CYP3A4 substrate may increase exposure to the CYP3A4 substrate. Therefore, caution is warranted when dasatinib is coadministered with CYP3A4 substrates of narrow therapeutic index, such as astemizole, terfenadine, cisapride, pimozide, quinidine, bepridil or ergot alkaloids (ergotamine, dihydroergotamine) (see section 4.5).
The concomitant use of dasatinib and a histamine-2 (H2) antagonist (e.g. famotidine), proton pump inhibitor (e.g. omeprazole), or aluminium hydroxide/magnesium hydroxide may reduce the exposure to dasatinib. Thus, H2 antagonists and proton pump inhibitors are not recommended and aluminium hydroxide/magnesium hydroxide products should be administered up to 2 hours prior to, or 2 hours following the administration of dasatinib (see section 4.5).
Special populations
Based on the findings from a single-dose pharmacokinetic study, patients with mild, moderate or severe hepatic impairment may receive the recommended starting dose (see sections 4.2 and 5.2). Due to the limitations of this clinical study, caution is recommended when administering dasatinib to patients with hepatic impairment (see section 4.2).
Important adverse reactions
Myelosuppression
Treatment with dasatinib is associated with anaemia, neutropenia and thrombocytopenia. Their occurrence is more frequent in patients with advanced phase CML or Ph+ ALL than in chronic phase CML. Complete blood counts should be performed weekly for the first 2 months, and then monthly thereafter, or as clinically indicated. Myelosuppression was generally reversible and usually managed by withholding dasatinib temporarily or by dose reduction (see sections 4.2 and 4.8).
In a Phase III dose-optimisation study in patients with chronic phase CML with resistance or intolerance to prior imatinib therapy, grade 3 or 4 myelosuppression was reported more frequently in patients treated with 70 mg twice daily than in patients treated with 100 mg once daily.
Bleeding
In the Phase III study in patients with newly diagnosed chronic phase CML, 1 patient (< 1%) receiving dasatinib compared to 2 patients (1%) receiving imatinib had grade 3 or 4 haemorrhage. In clinical studies in patients with resistance or intolerance to prior imatinib therapy, severe central nervous system (CNS) haemorrhage occurred in < 1% of patients. Eight cases were fatal and 6 of them were associated with Common Toxicity Criteria (CTC) grade 4 thrombocytopenia. Grade 3 or 4 gastrointestinal haemorrhage occurred in 4% of patients with resistance or intolerance to prior imatinib therapy and generally required treatment interruptions and transfusions. Other grade 3 or 4 haemorrhage occurred in 2% of patients with resistance or intolerance to prior imatinib therapy. Most bleeding related events in these patients were typically associated with grade 3 or 4 thrombocytopenia (see section 4.8). Additionally, in vitro and in vivo platelet assays suggest that SPRYCEL treatment reversibly affects platelet activation.
Patients were excluded from participation in initial SPRYCEL clinical studies if they took medicinal products that inhibit platelet function or anticoagulants. In subsequent studies, the use of anticoagulants, acetylsalicylic acid, and non-steroidal anti-inflammatory drugs (NSAIDs) was allowed concurrently with SPRYCEL if the platelet count was > 50,000-75,000/mm3. Caution should be exercised if patients are required to take medicinal products that inhibit platelet function or anticoagulants.
Fluid retention
Dasatinib is associated with fluid retention. In the Phase III clinical study in patients with newly diagnosed chronic phase CML, grade 3 or 4 fluid retention was reported in 2 patients (1%) in each of the dasatinib and the imatinib-treatment groups (see section 4.8). In clinical studies in patients with resistance or intolerance to prior imatinib therapy, grade 3 or 4 fluid retention was reported in 10% of patients, including grade 3 or 4 pleural and pericardial effusion reported in 7% and 1% of patients, respectively. In these studies, grade 3 or 4 ascites and generalised oedema were each reported in < 1% of patients, and grade 3 or 4 pulmonary oedema was reported in 1% of patients.
Patients who develop symptoms suggestive of pleural effusion such as dyspnoea or dry cough should be eva luated by chest X-ray. Grade 3 or 4 pleural effusion may require thoracocentesis and oxygen therapy. Fluid retention events were typically managed by supportive care measures that include diuretics and short courses of steroids (see sections 4.2 and 4.8). While the safety profile of SPRYCEL in the elderly population was similar to that in the younger population, patients aged 65 years and older are more likely to experience fluid retention events and dyspnoea and should be monitored closely. Fluid retention was reported less frequently in patients treated with once daily schedule compared to twice daily in two Phase III dose-optimisation studies (see section 4.8).
Pulmonary arterial hypertension (PAH)
PAH (pre-capillary pulmonary arterial hypertension confirmed by right heart catheterization) has been reported in association with dasatinib treatment in post-marketing reports (see section 4.8). In these cases, PAH was reported after initiation of dasatinib therapy, including after more than one year of treatment.
Patients should be eva luated for signs and symptoms of underlying cardiopulmonary disease prior to initiating dasatinib therapy. An echocardiography should be performed at treatment initiation in every patient presenting symptoms of cardiac disease and considered in patients with risk factors for cardiac or pulmonary disease. Patients who develop dyspnoea and fatigue after initiation of therapy should be eva luated for common etiologies including pleural effusion, pulmonary oedema, anaemia, or lung infiltration. In accordance with recommendations for management of non-haematologic adverse reactions (see section 4.2) the dose of dasatinib should be reduced or therapy interrupted during this eva luation. If no explanation is found, or if there is no improvement with dose reduction or interruption, the diagnosis of PAH should be considered. The diagnostic approach should follow standard practice guidelines. If PAH is confirmed, dasatinib should be permanently discontinued. Follow up should be performed according to standard practice guidelines. Improvements in haemodynamic and clinical parameters have been observed in dasatinib-treated patients with PAH following cessation of dasatinib therapy.
QT Prolongation
In vitro data suggest that dasatinib has the potential to prolong cardiac ventricular repolarisation (QT Interval) (see section 5.3). In 258 dasatinib-treated patients and 258 imatinib-treated patients in the Phase III study in newly diagnosed chronic phase CML, 1 patient (< 1%) in each group had QTc prolongation reported as an adverse reaction. The median changes in QTcF from baseline were 3.0 msec in dasatinib-treated patients compared to 8.2 msec in imatinib-treated patients. One patient (< 1%) in each group experienced a QTcF > 500 msec. In 865 patients with leukaemia treated with dasatinib in Phase II clinical trials, the mean changes from baseline in QTc interval using Fridericia's method (QTcF) were 4 - 6 msec; the upper 95% confidence intervals for all mean changes from baseline were < 7 msec (see section 4.8).
Of the 2,182 patients with resistance or intolerance to prior imatinib therapy who received dasatinib in clinical studies, 14 (< 1%) had QTc prolongation reported as an adverse reaction. Twenty-one of these patients (1%) experienced a QTcF > 500 msec.
Dasatinib should be administered with caution to patients who have or may develop prolongation of QTc. These include patients with hypokalaemia or hypomagnesaemia, patients with congenital long QT syndrome, patients taking anti-arrhythmic medicinal products or other medicinal products which lead to QT prolongation, and cumulative high dose anthracycline therapy. Hypokalaemia or hypomagnesaemia should be corrected prior to dasatinib administration.
Cardiac adverse reactions
Dasatinib was studied in a randomised trial of 519 patients with newly diagnosed CML in chronic phase which included patients with prior cardiac disease. The cardiac adverse reactions of congestive heart failure/cardiac dysfunction and fatal myocardial infarction were reported in patients taking dasatinib. Adverse cardiac events were more frequent in patients with risk factors or a history of cardiac disease. Patients with risk factors (e.g. hypertension, hyperlipidemia, diabetes) or a history of cardiac disease (e.g. prior percutaneous coronary intervention, documented coronary artery disease) should be monitored carefully for clinical signs or symptoms consistent with cardiac dysfunction such as chest pain, shortness of breath, and diaphoresis.
If these clinical signs or symptoms develop, physicians are advised to interrupt dasatinib administration. After resolution, a functional assessment should be performed prior to resuming treatment with dasatinib. Dasatinib may be resumed at the original dose for mild/moderate events ( grade 2) and resumed at a dose level reduction for severe events ( grade 3) (see section 4.2). Patients continuing treatment should be monitored periodically.
Patients with uncontrolled or significant cardiovascular disease were not included in the clinical studies.
Lactose
This medicinal product contains 135 mg of lactose monohydrate in a 100 mg daily dose and 189 mg of lactose monohydrate in a 140 mg daily dose. Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicinal product.
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