Clofarabine (Evoltra®) is recommended for use within NHS Wales for the treatment of acute lymphoblastic leukaemic (ALL) in paediatric patients (≤ 21 yrs) who have relapsed or are refractory after receiving at least two prior regimens and where there is no other treatment option anticipated to result in a durable response. Treatment is restricted to patients in whom there is an intention to proceed to stem cell transplantation and who are under the care of a paediatric haemato-oncologist, as it is not cost effective when used for palliation.