Tavalisse
(fostamatinib)Dosage & Administration
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Tavalisse Prescribing Information
TAVALISSE is indicated for the treatment of thrombocytopenia in adult patients with chronic immune thrombocytopenia (ITP) who have had an insufficient response to a previous treatment.
Recommended Dosage
Initiate TAVALISSE at a dose of 100 mg taken orally twice daily. After a month, if platelet count has not increased to at least 50 × 109/L, increase TAVALISSE dose to 150 mg twice daily.
Use the lowest dose of TAVALISSE to achieve and maintain a platelet count at least 50 × 109/L as necessary to reduce the risk of bleeding.
TAVALISSE may be taken with or without food. In the case of a missed dose of TAVALISSE, instruct patients to take their next dose at its regularly scheduled time.
Monitoring
After obtaining baseline assessments:
- Monitor CBCs, including platelet counts, monthly until a stable platelet count (at least 50 × 109/L) is achieved. Thereafter, continue to monitor CBCs, including neutrophils, regularly.
- Monitor liver function tests (LFTs) (e.g., ALT, AST, and bilirubin) monthly.
- Monitor blood pressure every 2 weeks until establishment of a stable dose, then monthly thereafter.
Dose Modification for Adverse Reactions
TAVALISSE dose modification is recommended based on individual safety and tolerability. Management of some adverse reactions may require dose-interruption, reduction, or discontinuation.
A dose reduction schedule is provided in Table 1, based on daily dose. For example, if a patient is on the maximum dose at the time of an adverse reaction, the first dose reduction would be from 300 mg/day to 200 mg/day.
| Daily Dose | Administered as: | |
|---|---|---|
| AM | PM | |
| ||
| 300 mg/day | 150 mg | 150 mg |
| 200 mg/day | 100 mg | 100 mg |
| 150 mg/day | 150 mg * | --- |
| 100 mg/day † | 100 mg * | --- |
The recommended dose modifications for adverse reactions are provided in Table 2.
| Adverse Reaction | Recommended Action |
|---|---|
| ALT = alanine aminotransferase; AST = aspartate aminotransferase; BP = blood pressure; BL = bilirubin; ULN = upper limit of normal; LFT = liver function tests (AST, ALT, total BL with fractionation if elevated, alkaline phosphatase); AST/ALT = AST or ALT | |
| Hypertension | |
| Stage 1: systolic between 130-139 or diastolic between 80-89 mmHg |
|
| Stage 2: systolic at least 140 or diastolic at least 90 mmHg |
|
| Hypertensive crisis: systolic over 180 and/or diastolic over 120 mmHg |
|
| Hepatotoxicity | |
| AST/ALT is 3 × ULN or higher and less than 5 × ULN | If patient is symptomatic (e.g., nausea, vomiting, abdominal pain):
|
If patient is asymptomatic:
| |
| AST/ALT is 5 × ULN or higher and total BL is less than 2 × ULN |
|
| AST/ALT is 3 × ULN or higher and total BL is greater than 2 × ULN |
|
| Elevated unconjugated (indirect) BL in absence of other LFT abnormalities |
|
| Diarrhea | |
| Diarrhea |
|
| Neutropenia | |
| Neutropenia |
|
Dose Modification for Drug Interactions
Concomitant use with a strong CYP3A4 inhibitor increases exposure to R406 (the major active metabolite). Monitor for toxicities of TAVALISSE that may require TAVALISSE dose modifications (see Table 1) when given concurrently with a strong CYP3A4 inhibitor [see Drug Interactions (7.1)].
Discontinuation
Discontinue TAVALISSE after 12 weeks of treatment if the platelet count does not increase to a level sufficient to avoid clinically important bleeding [see Clinical Studies (14)].
TAVALISSE is available as:
- 100 mg tablet: orange, film-coated, round, biconvex tablets debossed with "100" on one side and "R" on the reverse side.
- 150 mg tablet: orange, film-coated, oval, biconvex tablets debossed with "150" on one side and "R" on the reverse side.
Pregnancy
Risk Summary
Based on findings from animal studies and the mechanism of action, TAVALISSE can cause fetal harm when administered to a pregnant woman [see Clinical Pharmacology (12.1)].
There are no available data in pregnant women to inform the drug-associated risk. In animal reproduction studies, administration of fostamatinib to pregnant rats and rabbits during organogenesis caused adverse developmental outcomes that were directly attributed to exposure in utero to the major fostamatinib metabolite (R406) at maternal exposures (AUC) as low as 0.3 and 10 times the exposure in patients at the maximum recommended human dose (MRHD), respectively (see Data). Advise pregnant women of the potential risk to a fetus.
All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively. An estimated background risk of major birth defects and miscarriage for the chronic ITP population is 8% and 4-11%, respectively.
Data
Animal Data
In a fertility and early embryonic development study in female rats, fostamatinib was administered orally for 15 days before mating to Day 7 of pregnancy, which caused a slight decrease in pregnancy rates and an increase in post-implantation loss were seen at maternal doses approximately 4.2 times the dose in patients at the MRHD.
In embryo-fetal development studies, pregnant animals were orally administered fostamatinib during the period of organogenesis at doses up to 25 and 50 mg/kg/day in rats and rabbits, respectively. The adverse developmental outcomes included an increase in embryo-fetal mortality (post-implantation loss), alterations to growth (lower fetal weights), and structural abnormalities (variations and malformations). These effects occurred at maternal exposures (AUCs) of 3,763 ng.h/mL in rats and 111,105 ng.h/mL in rabbits that were approximately 0.3 and 10 times the human exposure at the MRHD in rats and rabbits, respectively.
In a peri and postnatal development study in rats, fostamatinib was orally administered at doses of 2.5, 12.5, and 25 mg/kg/day from gestation day 7 until lactation day 20. The dose of 25 mg/kg/day was associated with maternal toxicity, including decreased body weights, body weight gains, and food consumption. At doses as low as 12.5 mg/kg/day fostamatinib caused increases in newborn mortality (neonatal mortality), alterations in growth and/or development (lower neonatal weights into post-weaning and structural abnormalities [malformations]). Functional impairment (delayed sexual maturation) was observed at 25 mg/kg/day. There was no evidence of neurobehavioral defects (maze learning and shuttle box avoidance) or immunological compromise (influenza host resistance challenge) in the F1 generation or latent untoward effects in the F2 generation. The maternal doses were approximately 2.1 and 4.2 times the MHRD in patients.
Lactation
Risk Summary
There are no data on the presence of fostamatinib and/or its metabolites in human milk, the effects on the breastfed child, or on milk production. In rodents, R406 (the major active metabolite) was detected in maternal milk in concentrations 5- to 10-fold higher than in maternal plasma. Because of the potential for serious adverse reactions in a breastfed child from TAVALISSE, advise a lactating woman not to breastfeed during treatment with TAVALISSE and for at least 1 month after the last dose.
Females and Males of Reproductive Potential
Pregnancy Testing
Based on animal studies, TAVALISSE can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)]. For females of reproductive potential, verify pregnancy status prior to initiating TAVALISSE.
Contraception
Females
Based on animal studies, TAVALISSE can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)]. Advise females of reproductive potential to use effective contraception during treatment with TAVALISSE and for at least 1 month after the last dose.
Infertility
There are no data on the effect of TAVALISSE on human fertility. Based on the finding of reduced pregnancy rates in animal studies, TAVALISSE may affect female fertility [see Use in Specific Populations (8.1)].
Pediatric Use
Safety and effectiveness in pediatric patients have not been established. TAVALISSE is not recommended for use in patients less than 18 years of age because adverse effects on actively growing bones were observed in nonclinical studies. In subchronic, chronic, and carcinogenicity studies of TAVALISSE, chondrodystrophy of the femoral head was seen in rodents. In a study in juvenile rabbits, growth plate dysplasia was observed in the proximal femur and femoro-tibial joint, and bone marrow cellularity was reduced in the femur and sternum.
Geriatric Use
Of the 102 patients with ITP who received TAVALISSE, 28 (27%) were 65 years of age and older, while 11 (11%) were 75 years of age and older. In patients 65 years of age and older, 6 (21%) patients experienced serious adverse events and 5 (18%) experienced adverse events leading to treatment withdrawal while in patients under 65 years of age, 7 (9%) and 5 (7%) experienced serious adverse events and adverse events leading to treatment withdrawal, respectively. In patients 65 years of age and older who received TAVALISSE, 11 (39%) patients experienced hypertension versus 2 (18%) placebo compared to 17 (23%) in patients under 65 of age versus 4 (11%) placebo. No overall differences in effectiveness were observed in these patients compared to younger patients.
None.
Hypertension
Hypertension can occur with TAVALISSE treatment; hypertensive crisis occurred in 1% of patients. Patients with pre-existing hypertension may be more susceptible to the hypertensive effects of TAVALISSE.
Monitor blood pressure every 2 weeks until stable, then monthly and adjust or initiate antihypertensive therapy to ensure maintenance of blood pressure control during TAVALISSE therapy. If increased blood pressure persists despite appropriate therapy, TAVALISSE interruption, reduction or discontinuation may be necessary [see Dosage and Administration (2.3)].
Hepatotoxicity
Elevated liver function tests (LFTs), mainly ALT and AST, can occur with TAVALISSE.
In the placebo-controlled studies, laboratory testing showed maximum ALT/AST levels more than 3 × the upper limit of normal (ULN) in 9% of patients receiving TAVALISSE [see Adverse Reactions (6.1)]. For most patients, transaminases recovered to baseline levels within 2 to 6 weeks of dose-modification.
Monitor liver function tests monthly during treatment. If ALT or AST increase more than 3 × ULN, manage hepatotoxicity using TAVALISSE interruption, reduction, or discontinuation [see Dosage and Administration (2.3)].
Diarrhea
Diarrhea occurred in 31% of patients treated with TAVALISSE. Severe diarrhea occurred in 1% of patients treated with TAVALISSE. Monitor patients for the development of diarrhea. Manage diarrhea using supportive care measures, including dietary changes, hydration and/or antidiarrheal medication, early after the onset of symptoms. Interrupt, dose reduce, or discontinue TAVALISSE if diarrhea becomes severe (Grade 3 or above) [see Dosage and Administration (2.3)].
Neutropenia
Neutropenia occurred in 6% of patients treated with TAVALISSE; febrile neutropenia occurred in 1% of patients.
Monitor the ANC monthly, and for infection during treatment. Manage toxicity with TAVALISSE interruption, reduction or discontinuation [see Dosage and Administration (2.3)].
Embryo-Fetal Toxicity
Based on findings from animal studies and its mechanism of action, TAVALISSE can cause fetal harm when administered to a pregnant woman. In animal reproduction studies, administration of fostamatinib to pregnant rats and rabbits during organogenesis caused adverse developmental outcomes including embryo-fetal mortality (post-implantation loss), alterations to growth (lower fetal weights), and structural abnormalities (variations and malformations) at maternal exposures (AUCs) approximately 0.3 and 10 times the human exposure at the maximum recommended human dose (MRHD), respectively. Advise pregnant women of the potential risk to a fetus. Advise females of reproductive potential to use effective contraception during treatment and for at least 1 month after the last dose. [see Use in Specific Populations (8.1) and Clinical Pharmacology (12.1)].