Therapeutic Interventions For Pain Induced By Vincristine Treatment For Childhood Acute Lymphoblastic Leukemia (ALL)

Patients with ALL on Total XVI ((or for those being treated "as per TOTXVI protocol") who
experience NP/PN after specific doses of vincristine are eligible to enroll in the study as
soon as the diagnosis of NP/PN related to VCR is established. The qualifying doses of
vincristine have been selected because they fall in the schedule of weekly vincristine doses
as per Total XVI, and 2 additional weekly vincristine doses are anticipated according to the
protocol. Participants will be randomized to receive gabapentin or placebo upon enrollment.
Morphine will be available to both groups as needed for pain at any time on the study. At the
time of enrollment, and daily thereafter until completion of the study drug, data will be
collected for pain assessment, and the daily dose of oral morphine used will be collected.
Data regarding the pain type, quality, and location, as well as treatments used to manage
pain will be assessed on a daily basis for the diagnostic event and for the period following
the next two administrations of VCR treated with the study drug.

Primary Objective: To assess the analgesic efficacy of gabapentin in controlling VCR-related
NP/PN in participants with ALL, by comparing the morphine daily dose (mg/kg/day) used to
control NP/PN as a primary or a rescue regimen in the gabapentin vs. placebo groups.

Secondary Objective: To compare the pain scores in the gabapentin and placebo groups as
recorded by pain score right now and pain score average for previous 24 hours.

Inclusion Criteria:

- Participant is enrolled on Total XVI or who are being treated "as per TOTXVI protocol"

- Participant is 1 year of age or older

- Participant has symptoms of NP/PN with onset no more than 7 days after one of the
following vincristine doses ± 3 days: protocol week 1, week 2 (induction), week 7
(reinduction I), or week 17 (reinduction II).

- Patient is expected to receive 2 doses of vincristine in weekly intervals as outlined
by the Total XVI protocol (or for those being treated "as per TOTXVI" protocol) while
on study drug (i.e. no known dosage reductions or planned missed doses).

Participant is able and willing to take oral medications.

Exclusion Criteria:

- Previous participation in this study

- Participant is receiving gabapentin for another indication at the time of diagnosis of
NP/PN or has received gabapentin previously.

- Pregnancy. Female participants of childbearing potential must have documented negative
urine or serum pregnancy test result not older than 7 days. Male patients with
reproductive potential will be counseled not to procreate during the study.

- Impaired renal function: decreased eGFR (<60ml/min/1.73m^2 as estimated by the revised
Schwartz equation)

- Participant has allergy or other contraindication for either morphine or gabapentin
therapy.

- Inability or unwillingness of research participant or legal guardian/representative to
give written informed consent.