PRIMARY OBJECTIVE:~I. To determine the safety and efficacy of avatrombopag for the treatment of thrombocytopenia after allogenic hematopoietic stem cell transplantation.~SECONDARY OBJECTIVE:~I. To identify predictors of response to avatrombopag.~OUTLINE:~Patients receive avatrombopag orally (PO) once daily (QD) for up to 1 year in the absence of disease progression or unacceptable toxicity. Avatrombopag will be titrated weekly until platelet count of greater than or equal to 60,000/uL is achieved and persists for 7 consecutive days, and the patient remains free from platelet transfusion.~After completion of study treatment, patients are followed up weekly for 4 weeks and then monthly up to 1 year.
This phase II trial studies the side effects and how well avatrombopag works for the treatment of thrombocytopenia after donor hematopoietic stem cell transplant. Thrombocytopenia is defined as abnormally low level of platelets in the blood. Avatrombopag is a small molecule thrombopoietin receptor agonist which stimulates thrombopoietin receptor leading to increase production of platelets.