NOPHO ALL-2008 Pilot Study on Consolidation Therapy for Children and Adolescents With Acute Lymphoblastic Leukemia

NOPHO ALL-2008 Pilot Study on Consolidation Therapy for Children and Adolescents With Acute Lymphoblastic Leukemia

Phase II Study of Individual 6-mercaptopurine(6MP) Dose Increments in Children With Acute Lymphoblastic Leukemia (ALL) Receiving High-dose Methotrexate (HDM) and PEG-asparaginase

The present pharmacokinetic (PK)-pharmacodynamic (PD) study will explore the toxicity and antileukemic response during the initial 3 months of individualised therapy of children and young adults with acute lymphoblastic leukemia (ALL). The investigators will on an individual toxicity-titrated basis attempt to increase the dose intensity of the 6-mercaptopurine used in the two-months post-remission treatment phase of lower risk childhood ALL. This will be performed together with continuous PEG-ASP (every 2nd week) and interspersed HD-MTX (5 g/m^2) every 3rd week. Thus, the trial will also test the feasibility of this particular drug combination.

In addition to the details above we will also explore the relationship of the post-HD-MTX MRD-levels with the dose of 6MP, TPMT-activity, DNA-6TGN, E-6TGN, E-MeMP, E-MTX, and presence of ASP-antibodies, the early development of anti-ASP antibodies during continuous PEG-ASP therapy. The study could improve the understanding of the pharmacodynamics of the 6MP/HD-MTX interaction in combination with PEG-ASP.

All patients received basic daily 6MP (6-mercaptopurine) (25 mg/m^2) and in addition high-dose methotrexate(HDM) every 3rd week (3 times HDM in total) and PEG-asparaginase every 14th day. Patients increased the dose of 6MP 2 weeks after each HDM if if the myelotoxicity had been acceptable. This means 2 increments since the study stopped 2 weeks after the last HDM

Standard dose 25 mg/m^2/day. Can be increased up to 75 mg/m^2/day if the myelosuppression is acceptable (ANC>0.5 T-count >50)

Toxicity of Treatment in Terms of Number of Participants With Serious Adverse Events or Adverse Events, Reported

Number of participants following the protocol treatment for the full consolidation therapy with toxicity in this pilot study trying to individually titrate 6-mercaptopurine to the highest tolerable level during Consolidation.

Incorporation of 6-thioguanine Nucleotides (6TGN) Into Leukocyte DNA, Development of Asparaginase Antibody Production

Biweekly bloodsamples during the 3 months are analyzed for 6TGN incorporation into leucocyte DNA. In addition Methylated Mercaptopurine (MeMP) and Erythrocyte-Methotrexate level is measured

Inclusion Criteria: B-lineage ALL 1-17.9 years WBC <100, clinical remission obtained day 2 Written consent to participation. Exclusion Criteria: t(9;22) Hypodiploidy 11q23-aberrations TPMT-deficiency Intolerance to MTX or 6MP

Data published (Frandsen et al, Br J Haematol Oct 2011) Anonymised data on individual patients can be provided by study chair (kschmiegelow@rh.dk) including studyno, gender, age, thiopurine methyltransferase status, immunophenotype, white blood cell count at diagnosis, dose increments at time point 1 and 2 for dose adjustment, and dose-limiting toxicities