Tosedostat (CHR2797) is an aminopeptidase inhibitor that has been investigated primarily for its potential in cancer therapy. It works by blocking the activity of intracellular aminopeptidases, enzymes that are involved in protein degradation and the regulation of key cellular processes. By inhibiting these enzymes, tosedostat disrupts amino acid metabolism in tumor cells, leading to amino acid deprivation, inhibition of protein synthesis, and ultimately cancer cell death. It has shown particular promise in hematological malignancies such as acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), where it can induce apoptosis in malignant cells while sparing normal hematopoietic cells. Tosedostat has also been studied in solid tumors, either as a single agent or in combination with chemotherapy or other targeted therapies, to enhance anti-tumor effects. Due to its mechanism of targeting tumor metabolism, tosedostat represents a novel approach in oncology, especially for cancers dependent on specific amino acids for growth and survival. Clinical trials have explored its efficacy and safety, focusing on optimizing dosing and identifying patient populations most likely to benefit.