To observe the clinical efficacy and safety of avatrombopag for chemotherapy-induced thrombocytopenia in patients with malignant tumors.

Tumor is one of the malignant diseases that people face. In 2015, the incidence of malignant tumors was about 3.929 million, and the annual growth rate is about 3.9%. Chemotherapy is currently the most commonly used treatment for patients with tumor, but chemotherapy also brings many other problems, such as thrombocytopenia which can leads to increased medical costs, chemotherapy cycles delayed, and chemotherapy doses reduced. Studies have found that the reduction of the chemotherapy dose and the delay of the chemotherapy cycle will affect the survival rate of patients. So it is an important to solve the problem of chemotherapy-induced thrombocytopenia.

Currently, there are some methods to treat thrombocytopenia such as platelet transfusion, rhTPO, rhIL-11 and other methods. However, these methods have some defects, platelets are at risk of ineffective transfusion, rhTPO may produce neutralizing antibodies and rhIL-11 has serious side effects. Therefore, there is an urgent need for safer and faster methods to treat chemotherapy-induced thrombocytopenia. As a new generation of TPO receptor agonist, avatrombopag has the advantages of being taken with food, no hepatotoxicity, good safety, and rapidly increase platelet count. Therefore, avatrombopag has great research value in the treatment of chemotherapy-induced thrombocytopenia.

Inclusion Criteria:

1. Male or female, aged 18~75 years.
2. Diagnosed with malignant tumors (gynecological tumors, gastrointestinal tumors, lung cancer, gastric cancer and head and neck tumors) by pathology or cytology and need chemotherapy.
3. The subject had developed at least grade II thrombocytopenia after the last chemotherapy cycle (10×109/L\