A 69 yo male who developed acute lymphoblastic leukemia was initially treated with HyperCVAD therapy. After a couple of rounds of vincristine, he experienced symptoms of peripheral neuropathy and the vincristine was stopped. Six months later he went into remission and additional therapy was held. His symptoms of neuropathy slowly improved. Unfortunately a year later he relapsed and was started on blinatumomab and intrathecal methotrexate and cytarabine. His neuropathy worsened again, even though he was not receiving vincristine and neuropathy is not a known side effect of blinatumomab.