Fostamatinib oral
- Drugs List
- Therapeutic Indications
- Dosage
- Contraindications
- Precautions and Warnings
- Pregnancy and Lactation
- Side Effects
- Monograph
Presentation
Oral formulations of fostamatinib.
Drugs List
Therapeutic Indications
Uses
Idiopathic thrombocytopenic purpura
Fostamatinib is indicated for the treatment of chronic immune thrombocytopenia (ITP) in adult patients who are refractory to other treatments.
Dosage
The lowest dose of fostamatinib to achieve and maintain a platelet count of at least 50,000 per microlitre should be used.
Fostamatinib treatment should be discontinued after 12 weeks if the platelet count does not increase to a sufficient level to avoid clinically important bleeding.
Adults
100mg twice daily. This can be increased to a dose of 150mg twice daily after 4 weeks based on platelet count and tolerability. A daily dose of 300mg must not be exceeded.
Additional Dosage Information
Missed dose
If a dose of fostamatinib is missed, patients should take their next dose at its regularly scheduled time.
Dose reduction schedule
Maximum dose
300mg/day. Administered as 150mg in the morning and 150mg in the evening.
First dose reduction
200mg/day. Administered as 100mg in the morning and 100mg in the evening.
Second dose reduction
150mg once daily, taken in the morning.
Third dose reduction
100mg once daily, taken in the morning.
Hypertension
Stage 1: systolic between 130mmHg and 139mmHg or diastolic between 80mmHg and 89mmHg
Initiate or increase dose of antihypertensive medication for patients with increased cardiovascular risk, adjust as needed until blood pressure is controlled. If blood pressure target is not met after 8 weeks, reduce fostamatinib to the next lower daily dose.
Stage 2: systolic at least 140mmHg or diastolic at least 90mmHg
Initiate or increase dose of antihypertensive medication, adjust as needed until blood pressure is controlled. If blood pressure remains 140mmHg over 90mmHg or higher for more than 8 weeks, reduce fostamatinib to the next lower daily dose. If blood pressure remains 160mmHg over 100mmHg or higher for more than 4 weeks despite aggressive antihypertensive treatment, interrupt or discontinue fostamatinib.
Hypertensive crisis: systolic over 180mmHg and/or diastolic over 120mmHg
Interrupt or discontinue fostamatinib. Initiate or increase dose of antihypertensive medication and adjust as needed until blood pressure is controlled. If blood pressure returns to less than the target, resume fostamatinib at the same daily dose. If blood pressure remains 160mmHg over 100mmHg or higher for more than 4 weeks despite aggressive antihypertensive treatment, discontinue fostamatinib.
Hepatotoxicity
AST/ALT is 3 x ULN or higher and less than 5 x ULN
If patient is symptomatic: Interrupt fostamatinib. Recheck liver function tests every 72 hours until ALT/AST values are no longer elevated and total bilirubin remains less than 2 x ULN. Resume fostamatinib at next lower daily dose.
If patient is asymptomatic: Recheck liver function tests every 72 hours until ALT/AST values are below 1.5 x ULN and total bilirubin remains less than 2 x ULN. Consider interruption or dose reduction of fostamatinib if ALT/AST and total bilirubin levels remain in this category (AST/ALT is 3 to 5 x ULN; and total bilirubin levels remain less than 2 x ULN). If interrupted, resume fostamatinib at the next lower daily dose when ALT/AST are no longer elevated and total bilirubin remains less than 2 x ULN.
AST/ALT is 5 x ULN or higher and total bilirubin is less than 2 x ULN
Interrupt fostamatinib treatment.Recheck liver function tests every 72 hours. If AST and ALT decreases, recheck until ALT and AST are no longer elevated (below 1.5 x ULN) and total bilirubin is less than 2 x ULN; resume fostamatinib at the next lower daily dose. If AST and ALT persist at 5 x ULN or higher for 2 weeks or more, discontinue fostamatinib.
Elevated unconjugated (indirect) bilirubin levels in absence of other liver function test abnormalities
Continue fostamatinib with frequent monitoring since isolated increase in unconjugated (indirect) bilirubin levels may be due to UGT1A1 inhibition.
Diarrhoea
If symptoms become severe (Grade 3 or above), temporarily interrupt fostamatinib. If diarrhoea improves to mild (Grade 1), resume fostamatinib at the next lower daily dose.
Neutropenia
If absolute neutrophil count decreases to less than 1 x 10 to the power 9 per litre and remains low after 72 hours, temporarily interrupt fostamatinib until resolved to greater than 1.5 x 10 to the power 9 per litre. Resume fostamatinib at the next lower daily dose.
Contraindications
Children under 18 years
Breastfeeding
Pregnancy
Severe hepatic impairment
Precautions and Warnings
Infection
UGT1A1 genetic polymorphism
Bone fractures
Hypertension
Osteoporosis
Treatment to be initiated and supervised by a specialist
Discontinue treatment immediately if pregnancy is suspected
Monitor blood pressure every 2 weeks until stable, then monthly
Monitor full blood count regularly
Monitor liver function in patients with hepatic impairment
Monitor liver function tests monthly during treatment
Monitor patient for signs of serious infection
Monitor patients who develop severe diarrhoea
Consider suspending/reducing dose if AST/ALT is 3-5 times ULN
Discontinue if AST or ALT level exceeds 5x ULN and persists
Discontinue if AST/ALT > 3 x ULN and bilirubin > 2 x ULN
Discontinue if BP remains at or above 160/100mmHg for more than 4 weeks
Discontinue if there is no evidence of clinical benefit within 12 weeks
Suspend if AST/ALT >5 x ULN and bilirubin less than or equal to 2 x ULN
Suspend therapy &/or reduce dose if neutrophil count <1 x 10 to power 9/L
Suspend treatment if grade 3 or greater diarrhoea occurs
Maintain treatment at the lowest effective dose
Female: Contraception required during and for 1 month after treatment
Breastfeeding: Do not breastfeed during & for 1 month after treatment
Monitor patients with osteoporosis, bone fractures or young adults where epiphyseal fusion has not yet occurred for any potential untargeted effects on bone remodelling or formation. The benefit/risk of continuing therapy during the healing of a bone fracture should be evaluated.
In the event of gastric upset, tablets may be taken with food.
Monitor complete blood counts, including platelet counts, monthly until a stable platelet count of at least 50,000 per microlitre has been achieved. Thereafter, continue to monitor complete blood counts, including neutrophils, regularly.
Pregnancy and Lactation
Pregnancy
Fostamatinib is contraindicated during pregnancy.
Use of fostamatinib during pregnancy is contraindicated by the manufacturer. Animal studies have shown foetal harm. Human data is limited and as such a potential risk cannot be ruled out.
Lactation
Fostamatinib is contraindicated during breastfeeding.
The manufacturer advises that the patient discontinues breastfeeding during treatment of fostamatinib and for at least one month after the last dose. Animal data reports excretion of fostamatinib metabolites in breast milk, however presence in human breast milk and the effects on exposed infants are unknown.
Side Effects
Abdominal pain
Alanine aminotransferase increased
Altered liver function tests
Aspartate aminotransferase increased
Bronchitis
Chest pain
Diarrhoea
Dizziness
Dysgeusia
Erythematous rash
Fatigue
Febrile neutropenia
Headache
Hypertension
Hypertensive crisis
Increased blood pressure
Increased bowel action
Increases in hepatic enzymes
Influenza-like syndrome
Lower respiratory tract infection
Macular rash
Nausea
Neutropenia
Pneumonia
Rash
Reduced neutrophil count
Respiratory tract infection
Upper respiratory tract infection
Overdosage
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 ).
Further Information
Last Full Review Date: September 2020
Reference Sources
Summary of Product Characteristics: Tavlesse film-coated tablets. Grifols UK Ltd. Revised August 2021.
NICE Evidence Services Available at: www.nice.org.uk Last accessed: 07 September 2020
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.