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Dasatinib - Response Time

I was only diagnosed around 6 weeks ago and have been on hydroxyurea until I started dasatinib 10 days ago.

My counts were as low as 25 when I was on hydroxyurea. I went for a blood test around the 3rd day on dasatinib and my white counts were up to around 75. I have another blood test for tomorrow, and I feel like they may still be high. Anyone have any ideas on the typical response time to dasatinib?

Side effects aren't bad yet, slight headaches but the last few days I have been achy and sore, it feels similar to my pre-diagnosis physical being.

Any insight would be great.

Hello Jeff,

Firstly, welcome and I hope you'll find the group useful. If you are willing could you give some background to your diagnosis: I.e. where you're being treated, white cell count at diagnosis, have you had a bone marrow biopsy, confirmed Philadelphia chromosome etc....

I'm unsure as to why you were on hydrox for so long - I assume you're not in the UK as you went straight to dasatinib. Is your doctor a CML specialist or general oncologist/hematologist?

I won't be able to offer 'medical' advice but I (and other forum members) should be able to offer questions for you to ask your doctor.

Chris

Hi Jeff and welcome,

HU is used to reduce the white cell count if, at diagnosis, it is high. This drug is not specific and targets white cells in general, so is not used for very long- just enough to get the wbc count down. In the scheme of CML, wbc of 75 is not that high, even though I can understand why you might worry that it has increased since your previous count when you were taking HU.
Dasatinib targets the PH+ cells specifically so may take a few weeks to kill all the PH+ cells in your peripheral blood so you can get into haematological remission (HR) which is you first goal after starting therapy.
As a 2nd generation TKI, almost 10 years data on dasatinib shows it to be highly effective especially as first line therapy in newly diagnosed chronic phase CML. It is available in first line in most countries (not currently in the UK but we live in hope!).

You need to be a little patient- 3 days on a TKI is probably too early to see a complete normalisation of white cell count.
In my own case, it took 3- 4 weeks to see my white count return to normal range.

I know its easy to say, but try not to stress too much. If you have been diagnosed in chronic phase CML then it is more than likely that you will respond well to dasatinib and will see a normalisation of your peripheral blood counts within 8 weeks if not sooner.

Chris has asked you for more detail of your diagnostics. It would help us to help you if you could let us know the answers. Once again, welcome - we are here to help and support.

Sandy

Hey guys, appreciate the responses, here is some additional info:

1) I was diagnosed with CML around June 30th. The reason it took so long to get on treatment meds is b/c I was diagnosed in Canada and I am getting treatment in the USA. My doc is a oncologist/hematologist at a research cancer center
2) My white count was 125 when I was diagnosed.
3) I have had a bone marrow biopsy
4) The philly chromosome is present, but it has a twist. It has pieces of chromosomes 9, 22 and 12.
5) I am 33 yrs old

I just went for another blood test today and my white count is down to 44!!! I was relieved to see some progress.

A small victory in the war but I will take it.

I will keep you guys posted on additional progress. Thanks again.

Hi Jeff,

that all makes sense - I did wonder if you were in the USA and that was what caused the delay. I think Sandy covered most of it really, in that you should look at a slightly longer timeframe for dasatinib to work its magic. Depending on the blood testing frequency, something you may see in the near future is the WBC undershoot - while your body adapts to the meds reducing the WBC, the drugs work a little too well; I think the lower end of normal is 4k and i dropped down to 2.5k for 1-2 weeks and then bounced back to normal. It's nothing to worry about, just something to be aware of and discuss with your doc if it does happen.

As you're in the USA, have you seen this document?:

http://www.nccn.org/patients/guidelines/cml/index.html

I just had a quick look through and it has improved significantly since last time i looked (it was quite good before). I recommend reading the whole thing, but pay particular attention to pages 48-63, which outline suggested targets or guidelines for when you should hit treatment milestones - these are the national guidelines which your doctor will be assessing your progress against. You will notice the document talks in terms of 3,6 & 18 month milestones and this is the scale you will eventually start thinking in.

I know the early days are scary and you want reassurance by seeing a response - it's already dropped to 44k and I'm sure it will keep heading in the right direction; dasatinib is an excellent medication but, if for some reason it does not work for you, then there are other TKI drugs you can take which are equally effective.

I was 32 at diagnosis (diagnosed in the USA, now living in the UK) and I'm now coming up to my 4 four 'cancerversary'. I'm doing fine on the meds and don't let the CML hold me back. I'm on nilotinib and I found the side effects come and then go as my body learned to tolerate the medication - I hope your experience is similar or better.

I wish you well on your journey, particularly in the early days as you get used to your new circumstances and please ask any questions you may have.

Chris