Phase I Open-Label Study of P1101 Followed by P1801 in Advanced Solid Tumors

The goal of this clinical trial is to learn the safety of sequential treatment with P1101 and P1801 in advanced solid tumors. It will also learn the maximum tolerated dose (MTD) of P1801. The main questions it aims to answer are: To evaluate the safety and tolerability of sequential treatment with P1101 and P1801 in patients with advanced solid tumors. To determine the maximum tolerated dose (MTD) of P1801. Participants will: Ttreated by 6 doses of P1101 once per 2 weeks (Q2W) at 450 mcg and then followed by the treatment with P1801 Q2W at the pre-determined dose level by cohort during each 28-day treatment cycle in the Dose Escalation Phase (Cohort 1-5). Once the MTD have been declared and for further characterize safety and clinical activity, additional patients with RCC or CRC will be enrolled into the tumor-specific expansion cohorts to receive the sequential administration of 6 doses of P1101 Q2W at 450 ug followed by P1801 Q2W at MTD. Patients will visit the clinic every two weeks during the treatment period for drug administration and physical examinations. All patients must complete the safety follow-up visits at the 30-, 90-, and 150-day after the last dose of study treatment. Upon completion of the safety follow up, patients will be followed for survival every 12 weeks until death or until the end of the study is reached, unless they withdraw consent or are lost to follow-up.