A Study of SY-1365 in Adult Patients With Advanced Solid Tumors

This study consists of two parts. Part 1 is a dose-escalation/safety evaluation to identify a dose and regimen for further evaluation in Part 2. SY-1365 will be administered intravenously weekly \& twice weekly for 3 weeks of each 4 week cycle. Dose escalation will proceed until the determination of the maximum tolerated dose (MTD) or a recommended dose and regimen for evaluation in Part 2 of the study. Part 1 was concluded in September 2018 with a total of 32 evaluable patients. Following the identification of a recommended dose and regimen from Part 1, the study entered Part 2 to further evaluate safety and the antitumor activity of SY-1365 in patients with select solid tumors, and to confirm target engagement and downstream pathway impact in patients with any solid tumor histology. Preliminary anti-tumor activity will be evaluated in up to approximately 102 evaluable patients in Part 2, with SY-1365 administered alone, in combination with carboplatin, or in combination with fulvestrant. Part 2 will consist of five cohorts: * Cohort 1: approximately 24 patients with advanced ovarian cancer with 3+ previous lines of treatment. Monotherapy * Cohort 2: approximately 24 patients with relapsed ovarian cancer with previous platinum therapy. SY-1365 + Carboplatin * Cohort 3: approximately 12 patients with clear cell ovarian cancer. Monotherapy * Cohort 4: approximately 20-30 patients with biopsy-accessible, advanced solid tumors of any histology. Monotherapy. * Cohort 5: approximately 12 patients with HR+ metastatic breast cancer post CDK4/6 + hormonal therapy treatment. SY-1365 + fulvestrant. Overall, the study may enroll up to approximately 137 evaluable patients across dose escalation (Part 1) and expansion cohorts (Part 2, Cohorts 1, 2, 3, 4, and 5).