I have been on 600mg imatinib since diagnosed 12/30/15. I was borderline accelerated/blast. Reached all milestones, MMR at 12 months. PCR has been a consistent.02/.03. Blood work has been great. Anyhow, at today’s appointment I made the case for a dose reduction to 400mg. He agreed, said to start now, see you in 3 months. Now I’m nervous, so I plan to start six weeks prior to the next visit late July. Need some advice on risk. Forgot to mention, no side effects or issues on 600mg.
You are here
Imatinib dose reduction
Destiny Trial Protocol for reducing from 400mg to 200 mg was monthly PCR tests for 12 months. Latest assessment of PCR data over that period shows that if it stays stable over the dose reduction TFR is worth going for, but if it drifts up a little over the 12 months then TFR is less likely to be successful, so data is useful to your further options. I'm assuming the same assumptions go for reducing from 600 to 400; unlikely to be much data about as that is quite unusual. Given what I know now if I was reducing from 600 to 400 I would want monthly PCR for at least 6 months. Lucky you for no side effects on 600mg, but I'd bet you will feel a benefit from the reduction. Where are you being seen?
Hi Tbrand,
Please post your history or at least your eight most recent dated PCR readings. Thanks.
600mg Imatinib/Gleevec for over four years is a hefty dosage.
Assuming you are plateaued and have been for at least a year, or more, you can safely begin dosage reduction. Beginning six weeks prior to your next quarterly test is wise and eliminates the need for any extra testing which most oncs are prone to want. Testing during Stop Trials is done monthly for the purpose of gathering statistics. You aren't part of a trial so there is no need.
If the result of your next quarterly test is equal to or less than 0.02/0.03,(whatever range your PCR has been in) then six weeks before your next quarterly test, you can reduce to 300mg if you want, and then you can continue this process, at your own speed, until you reach 100mg. There is a probability that you may experience withdrawal syndrome along the way.
From everything you said, it is likely that you have been on too much TKI for too long.
When CML has been at a low level for a prolonged period of time, generally, a year, or so, it typically only requires a minimal dose of TKI to control it.
Thanks for the input. I am from the US, Colorado. I am seen at the Rocky Mountain Cancer Center. My PCR has been consistent.02/.03 for 40 months. .028 was my first MMR value after 12 months treatment. I am perfectly ok with taking imatinib, just wondering the odds of sustaining MMR at the standard 400mg dose? or better to leave well enough alone? I pushed for the dose reduction and now I’m chicken.
Tbrand, TKIs are toxic medications and the less we take over the longterm the better off we are likely to be. Just because you haven't had any problems with the high dosage so far doesn't guarantee that you won't have problems at some time in the future.
For those who relapse during dosage reduction, a return to the prior TKI dosage and they invariably regains their previous MMR status.
CML at your low level 0.02/0.03 presents no danger to you. The same can't be said of Imatinib 600mg or even Imatinib 400mg longterm.
The odds of a successful dosage reduction are heavily in your favor even down to 200mg.
Younger people tend to tolerate TKIs better than older people but it is always advisable to be on the lowest TKI dosage possible, regardless of age. .
Many good points, unfortunately the picture is 40 years ago, but aside from cml in real good health, knock on wood!
Buzz, I was not part of the Destiny Trial, but my specialist still wanted monthly PCR during reduction as the trial showed 20-30% of people lost MMR and needed to increase dose, and he felt that 3 month gaps were too long to wait to see if that happened. Trends in PCR results during the reduction phase also gave information on the likelihood of further reduction being a good option, so I would still want monthly tests.