Combination Chemotherapy and Nelarabine in Treating Patients With T-cell Acute Lymphoblastic Leukemia or Lymphoblastic Lymphoma

This study is testing whether adding a drug called nelarabine to standard chemotherapy improves survival rates in children and young adults with T-cell leukemia or lymphoma (blood cancers that affect a specific type of immune cell). **You may be eligible if...** - You are under 30 years of age and have been newly diagnosed with T-cell acute lymphoblastic leukemia (T-ALL) or T-cell lymphoblastic lymphoma - Your cancer has been confirmed as T-cell type by laboratory testing - Your general health is adequate to tolerate intensive chemotherapy **You may NOT be eligible if...** - You have already received significant prior chemotherapy for this cancer - You have serious liver, kidney, or heart problems - You are pregnant or breastfeeding - You have a pre-existing nerve condition (peripheral neuropathy) Talk to your doctor to see if this trial is right for you.