The purpose of this study is to evaluate the preliminary efficacy, safety, tolerability and pharmacokinetics of KC1036 in participants with advanced recurrent or metastatic digestive system tumors.

This is an open label, non-randomized，phase 1b/2 study to explore the preliminary antitumor activity of KC1036 in patients with advanced recurrent or metastatic digestive system tumors under BID or QD regimen.

The study will consist of two parts:

Part 1: QD regimen

To evaluate the efficacy and safety of KC1036 in the treatment of advanced recurrent, unresectable and / or metastatic digestive system tumors under 60mg QD regimen.

Part 2: BID regimen

Dose-Escalation part : To explore the safety of KC1036 under 20mg BID, 30mg BID and 40mg BID in patients with advanced recurrent or metastatic digestive system tumors.

Dose-Expansion part : According to the results of Dose-Escalation, an appropriate BID regimen was selected for Dose-Expansion to evaluate the effectiveness and safety of KC1036 in patients with advanced recurrent, unresectable and / or metastatic digestive system tumors.

Inclusion Criteria:

• Histologically or cytologically confirmed malignant digestive system tumors;
• Patients with advanced recurrent, unresectable and / or metastatic digestive system tumors who have failed standard or conventional treatment:( definition of treatment failure: intolerable toxic and side effects, disease progression during treatment recurrence after treatment);
• Eastern Cooperative Oncology Group performance status score of 0 or 1;
• Life expectancy > 12 weeks;
• BMI≥18.0;
• Has adequate Hematologic, renal, and hepatic function;
• Patients should participate in the study voluntarily and sign informed consent.

Exclusion Criteria:

• Any patient who is known to have central nervous system (CNS) metastasis with clinical symptoms;
• Other kinds of malignancies;
• Gastrointestinal abnormalitiest;
• Cardiovascular and cerebrovascular diseases;
• Previous treatment with small molecule vascular targeting inhibitor；
• Prior anti-tumor therapies with chemotherapy, radiotherapy, hormonotherapy, biotherapy, immunotherapy, operation within 4 weeks before enrollment;
• Involved in other clinical trials within 4 weeks before enrollment;
• Major surgical procedure, open biopsy, or significant traumatic injury 4 weeks before enrollment;
• Uncontrolled massive ascites,pleural/pericardial effusion;
• Uncontrolled ongoing or active bacterial, viral or fungal infectious; Fever of unknown cause (> 38.5 ℃) occurred within 2 weeks before enrollment;
• Known history of human immunodeficiency virus (HIV) infection or current chronic or active hepatitis B or C infection ;
• Pregnant or lactating women or those who do not take contraceptives, including men;
• Any other metabolic dysfunction, abnormal physical examination findings, or clinical laboratory findings;
• Inability to comply with protocol required procedures.