This clinical trial is focused on patients with hematological malignancies, which are types of blood cancers. The study involves patients who are undergoing a procedure called allogeneic hematopoietic stem cell transplantation (HSCT) with a reduced intensity conditioning regimen. This regimen includes the use of medications such as Fludarabine, Melphalan, and anti-thymocyte globulin (ATG), which help prepare the body for the transplant. The purpose of the study is to understand how patients are exposed to a component of Fludarabine, known as F-Ara-A, during this treatment process.

Participants in the study will receive these medications intravenously, meaning they are given directly into a vein. The study will monitor the cumulative exposure to F-Ara-A, which means the total amount of this substance that the body is exposed to over time. The study will also look at how this exposure varies between different patients. This information will help researchers understand how the body processes these medications and how this might affect the outcomes of the transplant.

The study will follow patients over a period of time to observe various outcomes, such as survival rates and the body’s ability to recover blood cell counts after the transplant. Researchers will also examine how factors like body weight and kidney function might influence the levels of F-Ara-A in the body. This trial aims to gather important data that could improve the treatment process for patients undergoing stem cell transplants in the future.