<unk>  is an antineoplastic agent that is FDA approved for the treatment of active hairy Cell Leukemia. There is a Black Box Warning for this drug as shown here.  Common adverse reactions include neutropenia, fever, infections, fatigue, nausea and headache.
Cladribine
Ifosfamide
Fludarabine 
Mafosfamide
Cytarabine
Dihydroergocristine
Vidarabine
Clofarabine