Phase Ib Study of the Safety and Efficacy of Gemtuzumab Ozogamicin (GO) and Venetoclax in Patients With Relapsed or Refractory CD33+ Acute Myeloid Leukemia:Big Ten Cancer Research Consortium BTCRC-AML17-113

This is a Phase Ib Study to determine the Maximum Tolerated Dose (MTD) of Venetoclax in combination with Gemtuzumab Ozogamicin(GO) in subjects with relapsed/refractory acute myeloid leukemia. Using a standard 3+3 design, subjects will receive once cycle of combination therapy. After one cycle of combination therapy, subjects showing response will continue on to one cycle of consolidation therapy with GO\Veneoclax. Subjects who respond to combination therapy will continue on maintenance Venetoclax until progression or unacceptable toxicity.

Dose-limiting toxicity, defined as an adverse event related (possible, probably, or definite) to Venetoclax and/or Gemtuzumab fulfilling one of the following criteria:

criteria:

• Hematologic toxicity: treatment-related grade 3 or worse neutropenia and/or thrombocytopenia due to bone marrow hypocellularity present at the end of cycle one (day 28) with an additional 28 days allowed for count recovery (i.e. present at day 56); specifically grade 3 or worse neutropenia or thrombocytopenia with the bone marrow documented to be free of leukemic infiltration. Note: patients who enter the study with grade 3 or worse cytopenias will not be evaluable for hematologic dose-limiting toxicities.
• Non-hematologic toxicity: any grade 3 or worse treatment-related toxicity occurring within the first cycle (excluding grade 3-4 infections during cycle one).

The study will also evaluate the Overall Response Rate, Anti-leukemic activity, Relapse-free Survival (RFS), event-free survival (EFS) , and overall survival (OS). The study will evaluate quality of life using the European Organization for the Research and Treatment of Cancer 30 item questionnaire (EORTC QLQ-C30).