I'm guessing but I would be curious to know how much is Resistance vs. tolerance, and when talking about tolerance are we talking dangerous issues or quality of life. I am wondering how much of the tolerance is driven by the fact that there are other drug options.
It think as long as it keeps working for you, then that is good, I mean even with those stats, the majority still do well on it for extended period. Also, should it stop working, there are other drugs to try that will likely bring it back under control. There are two other TKI drugs approved, another one on the way, and another one behind that in trial. Then there are a number of other things like Interferon, multiple TKI therapy, vaccine trial, and ultimately a SCT if pushed to the last resort. All in all there are a lot of weapons in the arsenal. I think a lot of it also has to do with how well you have been responding. If you are 4+ years with mediocre response then eventually it may not be enough to keep under control and you would have to switch, but if you were 4+ years MMR, I think the odds of relapse are much much less.
Hi: If you have reached PCRU then your chances of relapsing are very small, as long as you continue to take your Gleevec. As for intolerance, everyone is different. I have seen people switch to another TKI with just an annoying feeling about the side effects and nothing serious. Others have had serious side effects and had to switch. I am on Gleevec for 11 years, and I am at PCRU for 9 years. I live with whatever side effects I get, and my worse ones are the foot and hand cramping. I do get the fatigue also, but I just keep going the best I can. If your on Gleevec for over 4 years, and doing good. Then just keep doing what your doing.
A molecular report shows the results of a "real-time quantitative Polymerase Chain Reaction test" or "PCR Test" as it is commonly called. It measures the percentage of BCR/ABL1 transcripts found in a blood or marrow sample. BCR/ABL1 is produced by the 9:22 translation that is believed to cause CML. To put it simply, your molecular report indicates that 6.5% of the cells in your test sample are positive for the CML mutation.
When you get to MMR that means you have a major molecular response which means a 1000 fold decrease in your CML cells from when you were diagnosed. This level varies from lab to lab. At labs that conform to the "International Standard" a MMR is 0.100% (one tenth percent). Other labs define a MMR differently so you need to check with your lab to find out what they consider "MMR". CML experts agree that MMR is a major goal of CML treatment because statistics show that below that point there is little chance of progression to the later stages of CML.
PCRU means "PCR Undetectable", that is that your level is below the sensitivity of the PCR test. Test sensitivity also differs from lab to lab. PCRU doesn't mean that one is CML free but merely that they are below the level of the test sensitivity of that particular lab.