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Changing to Second Gen TKI's


This is my first time on here and the conversations seem really useful and supportive. I was diagnosed with CML last June and have been on Imatinib which has got my BCR-ABL to c1%. I have had minimal side-effects and the battle has been largely a mental one, other than the initial shock and unpleasant tests and balancing doses with variable blood test results etc.
Consultants have now advised to move to Bosutinib which seems to have a lot more potential side effects. I'm sure there are very good medical reasons for this but I have also noticed more limited supplies of Imatinib recently.
Has anyone else switched treatments and with what results please? Is there any advice or suggestions for managing side effects and what to look out for?
Looking at the threads on here, this seems to be a very long-term battle with lots of ups and downs along the way. Getting help and support on here could be really invaluable. I'm also interested in alternative therapies for immune system and mental health support.
Thanks in advance for any experiences or recommendations.
Best wishes to everyone going through this.

Hi Jonty,

If you are a year in on treatment and down to 1%, that itself is a strong reason for switching. Ideally you’d be down to 0.1% by now. If you were a little bit more than that your doctor would probably persevere with imatinib, but 1% is a bit too high to ignore so a switch is the right idea.

Out of the 2nd-line, 2nd generation drugs bosutinib is generally considered the most ‘gentle’ and with lowest grade side effects. Dasatinib can he hard on lungs, nilotinib can be tough on your heart.

Don’t worry too much about the long list of documented side effects, the way these are put together is anything that was reported by patients during clinical trials has to be put down as a potential side effect. This is why you’ll see things like weight gain, and weight loss as side effects!

Bosutinib does have one very common side effect, which is quite strong diarrhoea. However this generally lasts a couple of weeks so don’t worry too much about it. It will pass (pardon the pun!).


Hi David,
Thanks for this advice - it is very re-assuring to hear from someone who has been involved in this field for so long (not by choice I'm sure!).
It sounds like getting below 1.0% and even 0.1% to 0.001% are hard yards and will take time, so the switch by consultants seems understandable.
If you or anyone else is interested or going through the same thing I would be pleased to keep in touch on here.
Wishing you all the best,

Hi Jonty, I’m in a very similar boat as you.
I was diagnosed in the UAE in August ‘23 after a routine work medical flagged a high WBC. I returned to the UK and couldn’t start treatment until I went through the NHS diagnosis process, this reconfirmed CML towards the end of September. Commenced Imatinib 400 mg and hit the 3 month target with 6.5%. Like you I suffered little side-effects and had no reason to think Imatinib wouldn’t do its job. My consultant scheduled a PCR @ 8 months ( her error )with the results returning a 3.6% level, the 9 month test returned an increased result of 5.2 % and the decision was made to move me to Dasatinib 100mg / day with a check for any mutations. Like you I was concerned about the side-effects, reading the patient info got me anxious, especially the risk of pleural effusion. I started just over 2 weeks ago and so far have only suffered horrendous headaches for around a week, hopefully they won’t return. I realise some side-effects can take time to materialise and pretty much take each day as it comes trying not to focus on what might happen. I’ve found that mindfulness has helped my mental health alot, reducing the anxiety CML creates and focusing on the here and now. I can recommend the ‘Balance ‘ phone app which has a no strings 1 year free subscription, it guides you through the different levels of meditation right from absolute beginner to advanced.

Our stories show how there are common progressions and challenges but each diagnosis and treatment seems quite individual. Hopefully we will all get to Treatment Free Remission in our own ways in our own time. I am on a stronger dose of Bosutinib (500mg) so really hoping for the best. Your mindfulness and wellbeing suggestions are most helpful. I'm going to experiment as well with nutrition and herbal medicine.
Best wishes to you on your journey back to health and keep in touch!


Be careful with herbal things - they can cause more harm than good, and can sometimes counteract the TKI you are taking.

It’s really tempting to think that if you eat lots of spinach, and take some herbs then you are improving your cancer situation. The stark reality is that doesn’t really help at all. Obviously eating well and exercising is good for your overall health, but the number one thing you can do for your CML is to make sure you take your medication every single day and do not miss doses. It’s the single most important thing you can do.


Thanks David

I will do and keep my consultant informed as well!

It's more to help optimise the immune system generally and promote wellbeing. But I take the point it must not negate the impact of the TKI, so will be careful.

I've been very careful to take medication every day and only a couple of close shaves so far.

Thanks for the insights - they really do help.

Best wishes

Definitely, it seems everyone navigates CML a little differently. This is the first thread I’ve responded to, but since my diagnosis I’ve found the forum a great source of information and support, knowing you’re not alone helps a great deal.

I’d second David’s advice on herbal supplements, I was warned by the hospital pharmacist to avoid these completely, I do take Vit D3, B12, K2 and magnesium complex daily, there’s many posts mentioning these supplements and the benefits, searching keyword ‘Supplements, vitamins ’ should list them.

Fingers crossed for you and hope the Bosutinib works well. Will definitely keep in touch.

Best wishes

I was on 600mg imatinib for 5years and held steady at .02. I asked for a dose reduction to 400 and a year later.12. Went on Sprycel 100mg and dropped to .03 in 1 month and have been .006 to .002 almost 3 years now. I should had switched years ago.

It seems Dasatinib is far more potent. My consultant did say they wanted a faster and deeper response and your reaction to Sprycel demonstrates this, hopefully it will work better for me too. Next PCR will tell.

I was on Imatinib over 10 years and it took me almost 5 to reach MMR (major molecular response). In hindsight I should have switched earlier. When I did switch I reached MR 5 in less than 8 months. As far as side effects for imatinib it was my experience that it took a little over a year before I started noticing anything. At first you brush it off, then you attribute it to something else and eventually, like I do now, I blame all my aches and pains on my TKI. Keep us in the loop on your progress. Good luck!

My latest PCR results came back @2.67% after 17 days of new the TKI, that’s a 3.5% drop from 6.17% 3 days prior to starting Dasatinib.

Seems it’s doing a better job than the Imatinib, nothing back on mutations yet, assuming there’s none or they aren’t resistant to the Dasatinib. Next PCR in 8 weeks, hope the downward trend continues.

That's very positive progress which must be encouraging. Hopefully the side effects are manageable as well. You've done well to get some results so quickly too. I'm Day 13 on Bosutinib and whilst initial blood tests are fine and side effects still minimal, I have to wait until June 11th for my first PCR on the new TKI with results to follow two weeks from then! Best wishes, Jonty.

Definitely taking these results as a positive. Side effects have been minimal, still the odd day when I feel tired, no GI issues, and nothing worse than Imatinib.

Fingers crossed 🤞 your PCR is good, let us know.

Best regards


Hi Jonty,

I was diagnosed with CML in June 2015. Like you, I never reached 0.1% MMR (or MR3 - Major Molecular Response - a key milestone) on Imatinib and was switched to Dasatinib in October 2017. I also never quite hit MMR again (although was very close at 0.13%). My Consultant switched me to Bosutinib in August 2018. My first PCR came back just below 0.1%, which meant it took over 3 years to hit MMR. However, my Liver Function Tests were abnormal and my ALT and AST levels spiked after 2 months to around 6 times what is considered to be a safe level. I had to come off Bosutinib in December 2018.

I was facing a 4th line TKI, something I never thought I would have to consider. My Consultant wanted me to switch to Nilotinib, which I wasn't keen on since it would involve fasting and possible cardiac/vascular side effects. After persuading my Consultant to let me switch back to Dasatinib in January 2019, I reached MMR straight away and I am currently at 0.007%. I know I am fortunate I was able to switch back to a TKI I had previously tried since NHS England rules have subsequently changed and will now only allow this after a failed TFR (Treatment Free Remission) attempt.

I don't want to alarm you about Bosutinib, but make sure you have regular Liver Function Tests and ask what the results are (mine were overlooked for weeks causing my AST/ALT levels to rise too high). On the plus side I did reach MMR on Bosutinib and I never experienced the dreaded diarrhoea (in fact only Dasatinib caused this problem for me). Don't despair at not reaching MMR yet. On this forum you will see there are many slow responders like myself and you will eventually reach this milestone and possibly even lower levels (I am currently at MR4, i.e. less than 0.01%). It's just a case of finding the right TKI for you. I hope Bosutinib is the one!

Take care


Hi James,

thanks for sharing your experiences. It sounds like you have made great progress and it also shows the importance of taking responsibility for your own health and having a view on what to monitor and what's right for you. i will bear this in mind. It is very helpful to share experiences as sometimes it feels very lonely to scour the internet and read about the disease and the only interactions are with medical staff every few weeks, who are making life-changing decisions for us. Thanks for your time and consideration.

Best wishes and keep in touch.