APG-2575 Single Agent or in Combination With Ibrutinib or Rituximab in Patients With Waldenström Macroglobulinemia

This is an open-label, multi-center Phase Ib/II study of safety, tolerability, efficacy and PK of APG-2575 as a single agent or in combination with other therapeutic agents including ibrutinib or rituximab. The study consists of the dose escalation and the dose expansion phases. The clinical trial will have multiple arms with ability to subsequently add more treatment arms based upon clinical activity of APG2575 in WM. Initially the study will contain 3 arms noted below, all the arms are independent. Arm A: APG-2575 will be administered as a single agent to determine the MTD/RP2D in subjects who are relapsed/resistant or intolerant to ibrutinib or other BTK inhibitors. The Dose escalation phase of APG-2575 as monotherapy will use mTPI-2 design. The starting target dose (using ramp-up if needed) is 400 mg (dose level; DL1) and will be increased to 600 mg (DL2), 800 mg (DL3) accordingly. Doses can be increased to higher level depending on safety and PK results based on discussions of the Investigators and Sponsor. APG-2575 will be administered orally once daily until time of progression or unacceptable toxicity. After the MTD/RP2D is determined, up to 12 additional patients will be enrolled at RP2D in dose-expansion phase to further evaluate safety and efficacy of APG-2575. Arm B: APG-2575 will be administered in combination with ibrutinib in subjects with previously untreated WM.