For case 1, He is close to MMR, but not there after 5 years. The only other approved TKI for children is nilotinib, but switching to another 2G-TKI will not be so effective. I have had similar cases and continued dasatinib as long as the number is very close to MMR. If ponatinib is available, it may be tried, but we do not know the doses for children yet while phase 1 studies are ongoing. We have published a case series. ( Br J Haematol 2020 Apr;189(2):363-368). I do not know how big the 11 yo is, but you may want to try 15-30 mg initially depending on his size. I would not take him to BMT from MUD.
Although Case 2 initially had AP, after so many years with PCR close to MMR, I would do the same as case 1. Children who present with AP do reasonably well as long as they achieve the response milestones. (Eur J Cancer. 2019 Jul;115:17-23. ) I might have considered BMT for this child earlier in the course, but after so many years with stable molecular level, I might take the same approach as case 1.
For both cases, asciminib would be a consideration, if the study is available in your area (NCT04925479) and they meet the criteria for failure or intolerance.
About the growth question, I have discussed use of growth hormone with some endocrinologists, most of them are reluctant to use it. There is little experience in the literature.
(Pediatr Hematol Oncol. 2020 Mar;37(2):99-108.) From my observation, children on TKI may have catch up growth in puberty, if the height ends up lower than the mid-parental height. We are hoping that the current asciminib study will show positive results for growth issue.
Thank you.
Nobuko