<qa>  What should be discontinued at least 48 hours prior to start of study drugs?9. Systemic chemotherapyradiotherapyinvestigational therapy within 14 days with the exception of hydroxyurea and steroids prior to starting therapy. For patients receiving ALL maintenance with 6-mercaptopurine, methotrexate, vincristine, and steroids - these agents should be discontinued at least 48 hours prior to start of study drugs. For patients on oral targeted therapies such as imatinib, dasatinib, ponatinib, - these agents should be discontinued at least 48 hours prior to start of study drugs. 