The clinical information on these three cases supported so far is sparse, as no quantitative information is given (minor or partial CCyR?; what is the precise transcript ratio of BCR-ABL1? has this ratio been determined in a certified lab?).
Case 1 has "no CyR" (no cytogenetic response) at months. However, the milestones published by Baccarani et al in 2013 are based on quantitative definitions of failure (failure means less than partial CyR at months 12) and also the pediatric guideline recently published by the I-BFM-consortium (de la Fuente et al. 2014, Br. J. Haematol. 167:33-47) are based on these adult guidelines. Thus, in this case I do not see the need to switch to tasigna, but recommend to repeat the cytogenetics of bone marrow at months 12 and follow the response by regular monitoring of BCR-ABL1 by quantitative PCR at two months intervals from peripheral blood.
Cases 2 and 3 are identical having achieved no major molecular response (MMR = ratio BCR-ABL1/ABL1 <= 0.1%) at months 12. This is suboptimal response as defined (literature see above), but not failure. Without precise quantitative information (is the transcript ratio 45% or is it just 0.2% ?) it is hard to give any recommendation. A switch to tasigna could be recommended, however, the drug is not yet licensed in pediatrics. If prescription without license is possible for children in your country than the dose -as deduced from adults and tolerated so far well in a pediatric trial (see below) -is 2 x daily each 260-300 mg/qm every 12 hours with an empty stomach and no food intake thereafter for another hour. Adults are treated with 2 x 300 mg or 2 x 400 mg. The phase I/II trial on Nilotinib (Tasigna) in children is conducted by Novartis. Please contact the national Novartis country representative to inquire for participation in Novartis trial CAMN 107 A2120. Nilotinib is availiable as capsules with 50 / 200mg strength.