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Dasatinib and BCR tests.

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Hello.

My name is Ben, and Im writing aboit my son Benji. He is 11. He was diagnosed in 2016 with CML + PH, ALL. As you can imagine this is very rare. So Ive enjoyed reading on this forum for years. Just signed up today.

Heres my question/ concern to anyone going through similar tests with BCR.

Past few years ge has been on 70mg. His bcr test is very low. Or doesnt show up at all. Example.
Oct 2019 .0000
Nov 2019 .006
Dec 2019 .0000
Feb 2020 .010
March up to 80mg
April .0000
June .002

Just to clarify he started at 65lbs. Now weighs 98 lbs. Which is one of the reasons they raised dose.
Any ideas on why these swings happen? Takes pill everyday sane time. Doesnt eat 2 hours before. One hour after.

Thank you.
Ben.

Hi Ben,

Welcome!

I'm just wondering why he avoids food before / after taking his pills. It's nilotinib, not dasatinib, that requires a fasting period. Or is there something with paediatric dosing of dasatinib that is different?

Those "swings" happen becuase PCR testing for BCR-Abl isn't a perfectly reproducable test. You could run the test on the same blood draw and you may get different results. You can read our PCR primer here: https://cmlsupport.org.uk/node/20097

Maybe it would help put your mind at ease if you looked at the numbers as absolutes, rather than %s.

  • Oct 2019 .0000 = none
  • Nov 2019 .006 = six in one hundred thousand
  • Dec 2019 .0000 = none
  • Feb 2020 .010 = ten in one hundred thousand
  • April .0000 = none
  • June .002 = two in one hundred thousand

In absolute terms they are all very very small numbers, and the bouncing around is more like statistical noise than an actual swing.

David.

Thanks for the reply. I was hoping you would step in. Im on my phone so please excuse the grammar.
We had invested in Alkaline water only for him and we didn't realize his stomach needed to be acidic for absorption. He got CDiff like 5 times.
So just as a precaution to acidity we separated food from eating cycle.
Yes overall he has been amazing. Stopped treatment for ALL 6 months ago after 42 months. Now he only takes Dasatinib.
I didnt think the numbers overall made a bid deal, but since he gained so much weigh over the years they wanted to adjust his med up a little to see if the fluctuations went away.
Other than a little nausea he has no side effects.
Ive seen videos online stating that being negative and showing positive is bad because they dont know how negative a person was in previous tests.
I heard there is a kid at our hospital who has been on this drug for 10 years and is now having side effect problems bad enough they may pull him off and see what happens.
I guess overall what does 5,10 + years or lifetime do to someone younger is the thing we are dealing with now.

Ben

Here's a really interesting study around acid needed to break down dasatinbib.

https://sci-hub.tw/https://journals.sagepub.com/doi/full/10.1177/1078155...

It basically says that where there is a problem with low-acid in the stomach (perhaps due to acid reducing medication) taking your TKI with a fizzy cola drink can significantly increase the amount of dasatinib broken down and made available to the body!

I know this can be very different with kids, but once I had a couple of years with consistently low results I started to reduce my dosage (discussed with doctor, of course!) and now down to 20mg of dasatinib and am maintaining the same response. Those fluctuations really are very time and are expected, especially in a lab with good machines and processes. If you want to get undetectable results, the best way to do it is find a crappy lab!!

David.