Phase 1a/1b Trial to evaluate the tolerability and safety of IBI101 monotherapy or in combination with Sintilimab in advanced solid tumor patients.

IBI101 and Sintilimab will be administered intravenously on Day 1 of every 21-day cycle. The DLT observation period is 21 days starting with the first dose taken on day 1. In the Phase Ia study, eight dose levels of IBI101 (0.01, 0.1, 0.3, 1, 3, 6, 10 and 15mg/kg) will be tested. In the Phase Ib study, four dose levels of IBI101 (1, 3, 6 and 10mg/kg), in combination with Sintilimab 200mg, will be tested. After completion of the dose escalation phase, two combination dose cohorts (IBI101 3mg/kg and 6mg/kg, in combination with Sintilimab 200mg) will be expanded to 10 patients each.

IBI101 is a recombinant fully humanized IgG1 anti-tumor necrosis factor receptor superfamily member 4 (OX40) monoclonal antibody.

Sintilimab is a recombinant fully humanized anti-programmed death 1 (PD1) monoclonal antibody.

Inclusion Criteria:

• Patients with locally advanced, recurrent or metastatic solid tumors who have failed standard treatment
• 18 to 75 years old
• Life expectancy ≥ 12 weeks
• At least 1 measurable lesion
• ECOG PS score 0 or 1
• Adequate organ and bone marrow function

Exclusion Criteria:

• Previous exposure to anti-OX40, anti-PD-1, anti-PD-L1, anti-PD-L2 antibody or other immune checkpoint inhibitors
• Exposure to any other investigational drug in the 4 weeks prior to 1st dose of investigational drug
• Exposure to anti-tumor agents in the 3 weeks prior to 1st dose of investigational drug
• Exposure to immunosuppressant in the 3 weeks prior to 1st dose of investigational drug
• Major surgery in the 4 weeks prior to 1st dose of investigational drug
• 30Gy radiation in the chest in the 6 months prior to 1st dose of investigational drug
• History of autoimmune disease
• Symptomatic CNS metastasis