Bioenvision has submitted a Marketing Authorization Application for clofarabine to the European regulatory authorities. Using the European Centralized Procedure, the application will be evaluated for the treatment of refractory or relapsed acute leukaemia in children. The EMEA accepted and validated the application and has commenced a marketing authorization review for clofarabine.

The filing was primarily based upon data from two pivotal Phase II trials of clofarabine in children with relapsed or refractory acute lymphoblastic leukaemia (ALL) and acute myeloid leukemia (AML). The trial results were presented at the 40th American Society of Clinical Oncology annual meeting in June 2004.

Clofarabine previously was granted Orphan Drug Designation in Europe for both ALL and AML because of its potential to treat these serious, life-threatening conditions and address unmet clinical needs.

Dr. Chris Wood, chairman and CEO of Bioenvision commented:
"Filing for approval of clofarabine in Europe triggers the official review process by the regulatory authorities which is critical to our ex-US clofarabine development strategy and coincides with the Food and Drug Administration's (FDA) review of a New Drug Application for use of the product in pediatric acute leukemias. Clofarabine continues to deliver impressive results in a variety of haematological malignancies."

In June 2004, the FDA accepted the filing of the New Drug Application (NDA 21-673) for clofarabine in the treatment of pediatric patients with refractory or relapsed acute leukaemia.

Clofarabine is a next-generation purine nucleoside antimetabolite. Nucleoside analogues are antimetabolites that affect DNA synthesis. Clofarabine was rationally designed to combine many of the favourable properties of the two most commonly used nucleoside analogs, fludarabine and cladribine, but is reported to have greater potency at damaging the DNA of Leukemia cells than these other agents.