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

The patient will be randomized into 2 groups and take DAT-2645 tablet daily. dosage is optimal dose-1 or optimal dose-2, 21day/ Cycle. The subject of this part is to optimize dosage and definite RP2D.

The study set 6 dose level cohorts in dose escalation part.On C0D1, patient take DAT-2645 one time (Single use), The dosage is same as his enrolled cohort dose level. if no DLT, 7 days later(C1D1), patients will continue taking DAT-2645 tablet daily, dasage is same as before, 21days/cycle.