Nelarabine for the treatment of patients with relapsed or refractory T-cell acute lymphoblastic leukemia or lymphoblastic lymphoma.

Nelarabine (506U78) is a soluble prodrug of 9- Darabinofuranosylguanine (ara-G), a deoxyguanosine derivative. Nelarabine has significant activity in patients with T-cell acute lymphoblastic leukemia (T-ALL) and lymphoma (T-LBL). Principal toxicity is grade 3 or 4 neutropenia and thrombocytopenia. Neurologic toxicity with Guillain-Barré syndrome, depressed level of consciousness, and peripheral neuropathy are concerning side effects. Nelarabine is well tolerated and has significant antitumor activity in T-ALL and T-LBL. Nelarabine was approved by the Food and Drug Administration for patients with T-ALL/LBL who failed at least two prior regimens. Nelarabine is being explored in children and will be explored in the near future in adults with newly diagnosed T-ALL.