This is a single-center, open label pilot trial where patients with primary ITP who require second line treatment will be offered avatrombopag at a reduced starting dose, adjusted thereafter according to the response and continued for up to 24 weeks. The study aims to acquire experience on use of avatrombopag and explore the efficacy and safety of lower starting dose of avatrombopag
Avatrombopag is an oral thrombopoietin receptor agonist that is licensed for chronic ITP. Avatrombopag is administered at a starting dose of 20 mg daily. Overshooting of platelet count is a frequent problem that occurs in 20 to 40% of the patients after initiating avatrombopag as recommended. In this open label, single arm, pilot study, we will start avatrombopag at a reduced starting dose of 20 mg every other day. The dose will be adjusted thereafter according to the platelet response. The study consists of 3 phases: Dose adjustment phase, a maintenance phase, and dose tapering/disconsolation and follow-up phase. The study aims to acquire experience on use of avatrombopag and explore the efficacy and safety of lower starting avatrombopag-dose, and assess the rate of sustained response off-treatment. The duration of treatment with avatrombopag is 6 months. The study is an investigator-initiated trial sponsored by Center for Transplantation and Blood Diseases. Medical City Complex, Baghdad Iraq.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
25
Description: Patients will start on avatrombopag 20 mg every other day for a week then the dose will be readjusted according to the platelet count.
hematology center / Medical City
Baghdad, Iraq
RECRUITINGTotal Response Time
Median cumulative number of weeks with platelet count \>50 x 109/L from time of Avatrombopag initiation to end of week 20. A period of 2 week will be deducted after IVIG and 4 weeks after dexamethasone.
Time frame: 20 weeks
TTR
Time from initiation of dose to first platelet count \> 50 x 109/L without any rescue therapy during the 2 weeks prior to the blood sampling.
Time frame: 20 weeks
Response by day 8
Number of patients achieving platelet count \> 50 x 109/L by day 8 without any rescue therapy during the 2 weeks prior to the blood sampling.
Time frame: 8 days
Rates of platelet overshoot.
Number of episode with platelet count \> 200 and \>400 x 109/L during the first 6 weeks after the initiation of avatrombopag.
Time frame: 6 weeks
Durable response rate.
Number of patients achieving 4 consecutive platelet counts \> 50 x 109/L between weeks 12 and 20 including the last count, without the use of rescue therapy, corticosteroids or any platelet elevating agent after week 6.
Time frame: 20 weeks
The rates of treatment failure.
Occurrence of treatment failure is defined as: Discontinuation of Avatrombopag and switching to another platelet elevating agent between weeks 6 and 20 due to non-response or intolerance to Avatrombopag or administration of rescue therapy after week 6 and Thrombocytopenia (platelet count \<30 x 109/L), high risk of bleeding or intolerance to avatrombopag.
Time frame: 20 weeks
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Bleeding complications during the study.
Number and severity of WHO bleeding events.
Time frame: 52 weeks
The safety of treatment with Avatrombopag.
Occurrence and severity of treatment emergent adverse events. Occurrence and severity of adverse events of special interest including arterial and venous thrombosis and bone marrow fibrosis (bone marrow biopsy showing MF2 or higher).
Time frame: 52 weeks
The changes in HRQoL during the study.
Change in of SF-36 (v1) questionnaires from baseline to weeks 20.
Time frame: 20 weeks
The rates of Sustained Response Off-Treatment (SROT) at week 52.
Occurrence of SROT defined as: A platelet count \> 30 x 109/L in all planned visits between the time of discontinuation of Avatrombopag and week 52 including week 52 and no administration of platelet elevating agent between weeks 20 and 52.
Time frame: 52 weeks