This is a clinical trial for adults who were diagnosed with the types of blood cancer acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), bcr-abl negative myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), or multiple myeloma (MM), that is ether not responding to standard treatments, the cancer has returned after standard treatment, or there is no standard therapy.

The main purpose of this study is to determine the safest dose and side effects of the study drug CB-5339 when given by itself to patients with AML, MDS, bcr-abl negative MPN, MDS/MPN or MM. Other purposes of the study are to see how the human body processes CB-5339 and if the cancer improves after taking CB-5339. 

CB-5339 has only been tested in humans in a limited capacity and is considered to be an investigational drug. An investigational drug means that it has not yet been approved by the U.S. Food and Drug Administration (FDA).   

CB-5339 is an oral medication that comes in the form of hard gelatin capsules and will be given in “cycles” that are 4 weeks in length without a scheduled break in between cycles. Participants may continue to take CB-5339 for as long as their disease is improving, and they are tolerating the study drug.   

The anticipated duration of the study participation is approximately 2 years, including 18 months of enrollment and 6 months of follow-up visits.