Avatrombopag in the Treatment of Adult Immune Thrombocytopenia With Autoantibodies

The subjects will receive avatrombopag treatment with an initial dose of 40mg once a day. Platelet counts will be obtained weekly during the first 4 weeks and then every 2 weeks until week 12 after treatment. The dose adjustment range is 20 mg per week to 40 mg per day to maintain the platelet level between 30×10\^9/L and 200×10\^9/L. If the platelet count does not reach to 30×10\^9/L after taking avatrombopag 40mg once a day for 4 consecutive weeks, the treatment will be stopped.