<p>*PF = progression free, PD = progressive disease</p><p>2<sup>nd</sup> Leukemia = secondary leukemia</p><p>**Substrates for the tissue polyamine exporter SLC3A2 include the sum of putrescine, N1AcSpd, N8AcSpd and DAS; D1C1 = day 1, cycle 1, D8C1 = day 8 cycle 1</p><p>***NA = samples not available</p><p>Rank-ordered PFS by DFMO dose, ODC genotype and urinary polyamines.</p