Cell Therapeutics, Inc. (CTI) recently received notification from the US Food and Drug Administration (FDA) that the partial clinical hold on tosedostat (IND 075503) has been removed and all studies underway may continue. Tosedostat is a first-in-class selective inhibitor of aminopeptidases, which are required by tumour cells to provide amino acids necessary for growth and tumor cell survival, and is under development for the treatment of blood-related cancers.

Tosedostat is currently being studied in the United States and European Union in investigator-sponsored and cooperative group-sponsored phase II trials in elderly patients with newly diagnosed and relapsed acute myeloid leukaemia (AML) and high-risk myelodysplastic syndromes (MDS).

"We are pleased that the FDA has responded favourably to the tosedostat clinical trial data provided and removed the partial clinical hold to allow further development of tosedostat in ongoing and future studies," said John Pagel, MD, PhD, associate member, Clinical Research Division, Fred Hutchinson Cancer Research Centre; associate professor, Medical Oncology Division, University of Washington School of Medicine; and principal investigator in the tosedostat first-line AML/MDS trial.

AML is a cancer characterized by the rapid growth of abnormal white blood cells that accumulate in the bone marrow and interfere with the production of normal blood cells. AML may develop from the progression of other diseases such as myelodysplastic syndrome (MDS), a blood cancer that also affects the bone marrow leading to a decrease in circulating red blood cells. AML is the most common acute leukaemia affecting adults, and its incidence increases with age. AML progresses rapidly and is typically fatal within weeks or months if left untreated. Although a substantial proportion of younger individuals who develop AML can be cured, AML in the elderly typically responds poorly to standard therapy with few complete remissions.

Tosedostat is an oral aminopeptidase inhibitor that has demonstrated significant anti-tumour responses in blood-related cancers and solid tumours in phase I–II clinical trials. CTI has an exclusive marketing and co-development agreement with Chroma Therapeutics Ltd. for drug candidate tosedostat in North, Central and South America.

CTI is a biopharmaceutical company committed to the development and commercialization of an integrated portfolio of oncology products aimed at making cancer more treatable.