This is an open-label, multi-center Phase Ib/II study of safety, PK, PD and efficacy of APG-2575 as a single agent or in combination with rituximab or ibrutinib in relapsed/refractory CLL/SLL patients.~This study consists of two parts: The first part is the APG-2575 single agent cohort expansion. The cohort expansion will be conducted at three dose levels of 400 mg, 600 mg, and 800 mg. And up to 15 patients are planned to be enrolled at each dose level.~The second part contains two arms: APG-2575 combined with rituximab (Arm A) and APG-2575 combined with ibrutinib (Arm B). Both the two arms consist of two stages: dose escalation stage (first stage) and dose expansion stage (second stage). The first stage is the study of APG-2575 dose escalation combined with rituximab/ibrutinib. APG-2575 dose escalates according to the standard 3+3 design, the initial dose is 200mg, the dose of APG-2575 will be increased in subsequent levels, to 400mg, 600mg, 800mg respectively. The second stage is the MTD/RP2D expansion stage. Once the respective MTD/RP2D of arms A and B is determined, up to 15 subjects in each MTD/RP2D dose level would be enrolled.~APG-2575 will be administered orally, once daily for consecutive 4 weeks as one cycle.~Rituximab, on cycle 1 day 8(C1D8): 375mg/m2; on cycles 2-6 day l(C2-6D1): 500mg/m2, a total of six infusions.~Ibrutinib 420 mg will be orally administered daily beginning from cycle 1 day 8 and continuously thereafter, every 4 weeks as a cycle.
The purpose of this study is to assess the safety, pharmacokinetic, pharmacodynamic and efficacy of APG-2575 single agent and in combination with other therapeutic agents in patients with relapsed/refractory CLL/SLL.