Extremely Low Dose of 6-mercaptopurine in a Chinese Child with Acute Lymphoblastic Leukaemia and Multiple Pharmacogenetic Mutations

What Is Known And Objectives: Thiopurines are cornerstone drugs in the treatment of acute lymphoblastic leukaemia (ALL), but their use can be complicated by the incidence of life-threatening leucopenia.

Case Description: We describe a case of a 6-year-old Chinese boy with B-ALL receiving extremely low dose of 6-mercaptopurine (only 4% of recommended dose) during the ALL maintenance therapy phase.

What Is New And Conclusion: Complex pharmacogenetic tests and TDM should be recommended in children with complicated ALL to highlight the large individual variability in the responses to 6-MP exposure and the associated adverse effects.