Fig 1.

Mercaptopurine (MP) dose intensity and genetic ancestry. For patients enrolled onto AALL03N1 protocol, MP dose was adjusted during maintenance therapy on the basis of host toxicities (myelosuppression and infections), and dose intensity was defined as ratio of prescribed dose over protocol planned dose (75 mg/mg² per day). Dose intensity was measured longitudinally over 6 months and is shown as single cumulative value for study period. Patients were grouped into five racial/ethnic categories on the basis of genetic ancestry. Genetically defined East Asians had lowest MP dose intensity (ie, most likely to be MP intolerant). P value was estimated by using Kruskal-Wallis test. Each box includes data between 25th and 75th percentiles, with horizontal line indicating median. Whiskers indicate maximal and minimal observations within 1.5× length of box.