Study CBX-250-001 is a Phase 1, open-label, dose-escalation study of CBX-250 in participants with relapsed/refractory AML, HR-MDS and CMML. Participants aged 12 years are planned to be enrolled. CBX-250 will initially be investigated on a fixed step-up dosing schedule. CBX-250 will be administered subcutaneously in 28-day cycles, with the first study drug dose administered on Cycle 1, Day 1. Cycle 1 will consist of a priming phase over 7 days, and a target phase over 28 days. Participants will continue CBX-250 until progressive disease (PD) or unacceptable toxicity. All subsequent treatment cycles will be 28 days.

This phase I trial tests the safety, side effects, and best dose of eltanexor in combination with venetoclax for the treatment of patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) that has come back after a period of improvement (relapsed) or that has not responded to previous treatment (refractory). Eltanexor works by trapping "tumor suppressing proteins" within the cell, thus causing the cancer cells to die or stop growing. Venetoclax is in a class of medications called B-cell lymphoma-2 (BCL-2) inhibitors. It may stop the growth of cancer cells by blocking Bcl-2, a protein needed for cancer cell survival. Giving eltanexor together with venetoclax may be safe, tolerable and/or effective in treating patients with relapsed or refractory MDS or AML.

Study ASTX030-01 is a multi-phase study comprising of Phases 1-3 Monotherapy arms and a Phase 1 Combination Therapy arm Phase 1 Monotherapy consists of an open-label Dose Escalation Stage (Stage A) using multiple cohorts at escalating dose levels of oral cedazuridine and azacitidine (only one study drug will be escalated at a time) followed by a Dose Expansion Stage (Stage B). Phase 2 Monotherapy is a randomized, open-label, crossover study to compare oral ASTX030 to subcutaneous (SC) azacitidine. Phase 3 Monotherapy is a randomized open-label crossover study comparing the final fixed dose of oral ASTX030 to SC azacitidine. Phase 1 Combination Therapy is an open-label, multicenter, randomized, exploratory study comparing ASTX030 and SC azacitidine in combination with venetoclax in participants with AML.

The duration of this multi-phase study is approximately 7 years.