Dose Escalation and Dose Expansion Phases: Serum Concentration of Tislelizumab

Dose Escalation Phase: Surufatinib 250 mg + Tislelizumab

Patients with advanced or metastatic solid tumors of any kind who had progressed on or were intolerant of standard therapies received surufatinib 250 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Escalation Phase: Surufatinib 300 mg + Tislelizumab

Patients with advanced or metastatic solid tumors of any kind who had progressed on or were intolerant of standard therapies received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort A: CRC

Patients with microsatellite stable, locally advanced or metastatic CRC that was previously treated with at least 3 prior lines of therapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort B1: Thoracic NETs

Patients with thoracic NET who had progressive, locally advanced or metastatic, low-to-intermediate grade (Grade 1 or Grade 2), well-differentiated NETs that progressed on at least 1 line of standard therapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort B2: GEP NETs

Patients with GEP NET who had progressive, locally advanced or metastatic, low-to-intermediate grade (Grade 1 or Grade 2), well-differentiated NETs that progressed on at least 1 line of standard therapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort C: SCLC

Patients with locally advanced or metastatic SCLC that was previously progressed on first-line chemotherapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort D: GC

Patients with microsatellite stable, PD-L1 ≥5%, locally advanced or metastatic adenocarcinoma of the stomach or gastroesophageal junction (GC) and were previously treated with at least 2 lines of standard therapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort E2: UPS

Patients with UPS who progressed on, or had discontinued due to intolerable toxicity to, at least 1 line of standard therapy or were unsuitable for standard frontline cytotoxic chemotherapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Dose Expansion Phase: Cohort F: ATC

Patients with locally advanced or metastatic ATC and who had a BRAFV600E mutation were previously treated with 1 line of systemic therapy (not including radiation therapy) with a BRAF-targeted therapy received surufatinib 300 mg orally QD in combination with tislelizumab 200 mg IV infusion Q3W until PD, unacceptable toxicity, withdrawal of consent, new anticancer therapy, lost to follow-up, or death.

Analysis denominator · Participants