This will be a phase I protocol of Vincristine, Dexamethasone, Doxorubicin, and PEG-asparaginase (VPLD) and metformin conducted in the Sunshine Project sites for children with recurrent ALL. All sites will be eligible to open this study, provided they agree to adhere to all study procedures and make a good faith effort to obtain all pharmacodynamic and pharmacokinetic evaluations requested.