- Drugs List
- Therapeutic Indications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
Oral formulations of avapritinib.
Unresectable or metastatic malignant gastrointestinal stromal tumour (GIST)
As monotherapy in adults for the treatment of unresectable or metastatic gastrointestinal stromal tumours (GIST) harbouring the platelet-derived growth factor receptor alpha (PDGFRA) D842V mutation.
300mg once daily.
Additional Dosage Information
Recommended starting dose if concomitant use with moderate CYP3A inhibitor: 100mg once daily.
Starting dose: 300mg once daily.
First dose reduction: 200mg once daily.
Second dose reduction: 100mg once daily.
Dose modifications for adverse reactions
Intracranial haemorrhage (all grades): Permanently discontinue.
Grade 1 cognitive effects: Continue at same dose or interrupt therapy until baseline or resolution. Resume at the same dose or at a reduced dose.
Grade 2 or 3 cognitive effects: Interrupt therapy until improvement to baseline, grade 1 or resolution. Resume at the same dose or at a reduced dose.
Grade 4 cognitive effects: Permanently discontinue.
Any other grade 3 or 4 adverse reaction: Interrupt therapy until grade 2 or lower, then resume at the same dose or at a reduced dose.
If a dose of avapritinib is missed, the patient to take the missed dose unless the next schedules dose is within 8 hours. If the dose has not been taken at least 8 hours prior to the next scheduled dose, then the dose should be omitted and treatment should be resumed with the next scheduled dose.
Children under 18 years
End stage renal disease
Long QT syndrome
Severe hepatic impairment
Severe renal impairment
Torsade de pointes
Precautions and Warnings
Family history of long QT syndrome
Predisposition to haemorrhage
History of cerebrovascular accident
History of torsade de pointes
History of transient ischaemic attack
Recent intracranial haemorrhage
Correct electrolyte disorders before treatment
Advise ability to drive/operate machinery may be affected by side effects
Anti-diarrhoeals may be required during treatment
Anti-emetics may be required during therapy
Maintain adequate hydration during therapy
Treatment to be initiated by specialist
Advise patient to take on an empty stomach 1 hr before or 2 hrs after food
Consult local policy on the safe use of oral anti-cancer drugs
Staff: Not to be handled by pregnant staff
Exclude pregnancy prior to initiation of treatment
Monitor hepatic function before treatment and regularly during treatment
Perform ECG before and during treatment
Monitor coagulation values
Monitor for signs of fluid retention
Monitor for signs of neurological toxicity
Monitor for signs of rapid weight gain may indicate severe fluid retention
Monitor full blood count regularly
Monitor serum electrolytes
Patients with fluid retention should be treated with diuretics
Advise patient to report new or worsening cognitive symptoms
Predisposition QT prolongation: Counsel patient on symptoms of arrhythmias
Advise patient to seek advice at first indications of pregnancy
Interrupt if grade 2 cognitive effects occur
Permanently discontinue if grade 4 cognitive effects occur
Permanently discontinue if intracranial haemorrhage occurs
Suspend treatment if grade 3 or greater adverse reaction occurs
Advise patient not to take St John's wort concurrently
Advise patient to avoid grapefruit products
Female: Contraception required during and for 1 month after treatment
Breastfeeding: Do not breastfeed during & for 2 weeks after treatment
Advise patient to avoid exposure to direct sunlight
Advise patient to use SPF 50+ sunscreen and lip balm during treatment
Patients who experience neurological signs and symptoms such as severe headache, vision problems, somnolence or focal weakness during treatment with avapritinib should report this to their healthcare professional immediately. Brain imaging by magnetic resonance imaging (MRI) or computed tomography (CT) may be performed.
Pregnancy and Lactation
Avapritinib is contraindicated during pregnancy.
The manufacturer states that avapritinib is not recommended during pregnancy. There are no data available in the use of avapritinib in pregnant women, however animal studies have shown reproductive toxicity.
Avapritinib is contraindicated during breastfeeding.
The manufacturer recommends that breastfeeding should be discontinued during avapritinib treatment and for 2 weeks after the final dose. It is unknown whether avapritinib or its metabolites are excreted in human milk, therefore a risk to the infant cannot be excluded.
Acute kidney injury
Changes in hair colour
Creatine phosphokinase increased
Gastroesophageal reflux disease
Impairment of mental skills
Increase in lactate dehydrogenase
Increase in serum transaminases
Loss of balance
Palmar-Plantar Erythrodysaesthesia syndrome
Prolongation of QT interval
Reduced lymphocyte count
Reduced neutrophil count
Reversible confusional states
Sensation of cold
Serum creatinine increased
White blood cell count decreased
It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.
The following number will direct the caller to the relevant local centre (0844) 892 0111
Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( www.toxbase.org ) or if this is unavailable at the backup site ( www.toxbasebackup.org ).
Last Full Review Date: February 2021
Summary of Product Characteristics: Ayvakyt 100mg, 200mg and 300mg film-coated tablets. Blueprint Medicines (Netherlands) B.V. Revised November 2020.
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Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content
FDB Disclaimer : FDB Multilex is intended for the use of healthcare professionals and is provided on the basis that the healthcare professionals will retain FULL and SOLE responsibility for deciding what treatment to prescribe or dispense for any particular patient or circumstance.