PRL3-Zumab in Patients With Advanced Solid Tumors

This is a multicenter, Phase II, open-label, single-dose-level (6 mg/kg) study of PRL3-zumab monotherapy in patients with unresectable or metastatic solid tumors. PRL3-zumab will be administered via intravenous (IV) infusion until discontinuation criteria are met (e.g., disease progression per RECIST v1.1/iRECIST, intolerable toxicity, or withdrawal of consent). Study Periods and Duration The study is divided into the following phases: * Screening Period: Day -21 to Day -1; all assessments must be completed prior to the first dose. * Treatment Period: One cycle is defined as 4 weeks, consisting of two infusions administered 2 weeks apart. * End-of-Treatment (EOT) Visit: To be conducted within 14 days of the last dose or treatment discontinuation. * Safety Follow-Up: A visit scheduled 30 days after the last dose. * Survival Follow-Up: Conducted every 3 months post-discontinuation via telephone or other appropriate methods until the data cutoff date. Assessments * Safety \& QoL: Safety assessments (including laboratory tests) will be performed prior to each infusion. Quality of Life (QoL) will be assessed at screening and every 8 weeks during treatment. * Tumor Imaging: Assessments will be performed at baseline and every 8 weeks following the initiation of study treatment, according to RECIST v1.1 and iRECIST. * Immunogenicity: Assessments will be performed pre-dose on Cycle 1 Day 1, and prior to infusions in Cycles 2, 4, and 6. For patients remaining on treatment, assessments will continue every 3 cycles thereafter. Pharmacokinetic (PK) profiles will be evaluated in two distinct subgroups of 10 patients each. For the intensive PK sampling subgroup, assessments are concentrated in the first three cycles: Cycle 1 monitoring includes Day 1 (pre-dose, end of infusion, 2, and 6 hours post-infusion), Day 2 (24 hours), Day 6 (120 hours), Day 10 (216 hours), and Day 15 (pre-dose). Following pre-dose samples on Cycle 2 (Days 1 and 15) and Cycle 3 (Day 1), a second inten