Venetoclax in Combination With Non-myeloablative Conditioning Allogeneic Haematopoietic Stem Cell Transplantation

Eligible patients are to be enrolled sequentially into one of 4 treatment Dose Levels (beginning with Dose Level A) to receive short-course venetoclax on day -11 to -6, followed by intravenous fludarabine 30mg/m2 daily (day -5 to -3) and intravenous cyclophosphamide 750mg/m2 daily (day -5 to -3). Allogeneic stem cell infusion will occur on day 0. In the dose-escalation phase of this 3+3 study, three patients are planned for each Dose Level. Dose Level A: venetoclax 100mg daily administered on day -11 to -6 (total venetoclax dose: 600mg) Dose Level B: venetoclax 100mg daily administered on day -11, followed by 200mg daily administered on day -10 to -6 (total venetoclax dose: 1100mg) Dose Level C: venetoclax 100mg daily administered on day -11, followed by 200mg daily administered on day -10, 400mg daily administered on day -9 and 600mg daily administered on day -8 to -6 (total venetoclax dose: 2500mg) Protocol-specific dose-limiting toxicitues (DLTs) will be assessed from the first dose of venetoclax up to day 30 post-transplant. Subjects will not be treated in a new cohort until all subjects in the previous cohort had completed the DLT evaluation period and ≤ 1 of 6 subjects had experienced a DLT. If ≥ 2 of 6 subjects experienced a DLT at Dose Level C, subjects will be treated at Dose B' as part of the dose-escalation phase of this study. Dose Level B': venetoclax 100mg daily administered on day -11, followed by 200mg daily administered on day -10 and 400mg daily administered on day -9 to -6 (total venetoclax dose: 1900mg) The maximum tolerated dose (MTD) is defined as the highest Dose Level at which ≤ 1 of 6 subjects had experienced a DLT. The dose-expansion phase involves recruitment of up to 12 patients at the MTD.