avapritinib: prescribing and clinical use
Focused clinical detail for use alongside current product information, local policy and patient-specific assessment.
avapritinib: clinical details
Prescribing considerations
- Confirm PDGFRA D842V status using a validated test before treatment.
- Treatment should be initiated by a clinician experienced in anticancer therapy.
- Assess intracranial and general bleeding risk, including anticoagulants, antiplatelets, thrombocytopenia and relevant cerebrovascular history.
- Review CYP3A inhibitors and inducers, QT-prolonging treatments and narrow-therapeutic-index CYP3A substrates.
- Consider hepatic function and note the lack of supporting evidence in severe renal impairment.
- Counsel about cognitive effects, photosensitivity, contraception and driving impairment.
Contraindications and cautions
- Hypersensitivity to avapritinib or any product excipient.
- Use particular caution with intracranial-haemorrhage risk factors, QT prolongation, electrolyte disturbance, significant hepatic impairment or medicines that increase bleeding or arrhythmia risk.
Monitoring
- Full blood count, including platelets
- Liver transaminases and bilirubin
- Clinical evidence of bleeding; coagulation parameters where indicated
- Memory, confusion and other cognitive changes
- Weight, oedema and respiratory symptoms
- Electrolytes and ECG where QT risk is present
- Hydration where diarrhoea or vomiting occurs
Clinical pharmacology
Avapritinib is a type 1 kinase inhibitor with activity against PDGFRA D842V and KIT D816V mutants. It is metabolised predominantly through CYP3A4 and CYP3A5 and can weakly inhibit CYP3A and several transport proteins.
Formulation and product differences
- The selected product is a film-coated oral tablet intended to be swallowed whole.
- Only the selected tablet SmPC was used for UK product-specific licensing and formulation information.
avapritinib preparations and strengths
Tablet
Route: Oral
Strengths: 25 mg, 50 mg, 100 mg, 200 mg, 300 mg
avapritinib interactions
The specialist team and pharmacist should review all prescribed, non-prescribed and herbal products.
Strong or moderate CYP3A inhibitors, including azole antifungals, clarithromycin, erythromycin, ritonavir and cobicistat
These can increase avapritinib exposure and adverse effects, so concurrent use should generally be avoided.
Grapefruit or grapefruit juice
Grapefruit can increase avapritinib exposure and should be avoided.
CYP3A inducers, including rifampicin, carbamazepine, phenytoin, phenobarbital and St John’s wort
These can substantially lower avapritinib exposure and reduce its effect, so concurrent use should be avoided.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.