A PARG Inhibitor DAT-2645 Monotherapy in Patients with Advanced/Metastatic Solid Tumors Harboring BRCA1/2 Loss of Function Alterations And/or Other Defects in the DDR Pathway

Inclusion Criteria: * Signed informed consent prior to initiation of any procedures in this study. * At least 18 years of age (inclusive). * Evidence of an DDR deficiency status in tumor tissue determined by validated testing method. * Patients with advanced or metastatic solid tumor who have failed standard of care therapy, or are unable to tolerate standard of care therapy, or unable to obtain/unwilling to receive standard therapy. Regardless of PARP inhibitors were used or not in previous treatment. * At least one measurable lesion by RECIST v1.1 criteria. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0\~2. * Life expectancy at least 3 months. * Adequate hematologic and non-hematologic function during the screening. * Women of childbearing potential must have a negative result of serum pregnancy test at screening. * Women of childbearing potential or male patients whose spouse have childbearing potential must agree to use a reliable and effective method of contraception during the study and for 6 months after the last dose of the study drug. Exclusion Criteria: * Patients who received systemic chemotherapy, small-molecule targeted drugs within 14 days or 5 half-lives (whichever is longer) prior to the first dose of study drug. * Patients who received biological anti-tumor drugs (including immunotherapy, target therapy, antibody-drug conjugate \[ADC\]) within 4 weeks prior to the first dose of the study drug. * Patients who have undergone major …