Going off drug therapy will most likely result in relapse for the majority of folks with CML. But a few have done it and have remained free of CML, some of them for years. The reason is not clear. There was a clinical trial in 2005 that took 12 people off Gleevec who had been PCR undetectable for over 2 years to see how many would relapse. They had monthly PCRs to carefully watch for signs of relapse. Half relapsed within a few months, but the other six did not relapse at all. Here is the article: http://bloodjournal.hematologylibrary.org/cgi/reprint/blood-2006-03-011239v1
Dr John Goldman, one of the most respected CML experts, says about this subject: "How long should IM [Gleevec] be continued in the responding [CML] patient? There is preliminary evidence that the incidence of disease progression in responders diminishes with each successive year on IM. Moreover, there is no suggestion that the incidence of toxicity increases with duration of treatment. Anecdotal evidence suggests that most patients who stop taking IM lose within weeks or months the response they did achieve. These facts taken together suggest that the best advice for individual patients responding to IM is that the drug should be continued indefinitely, although whether this should be at full dose (400 mg daily) or at reduced dose is not yet established. A small number of patients in whom BCR-ABL transcripts have been undetectable for more than 1 or 2 years have stopped taking IM for various reasons. In the largest series published thus far, 6 of 12 patients showed evidence of relapse at the molecular level within 5 months of stopping IM, but the other 6 remained in "complete molecular remission" at a median follow-up of 15 months. This observation does raise the intriguing possibility that IM continued for long enough might eradicate residual leukemia in selected patients, perhaps particularly in those who have previously been treated with interferon- alfa. In vitro studies however suggest that "quiescent" leukemia stem cells are highly resistant to IM, and thus some at least are likely to survive long term even in patients who achieve a complete molecular remission, a conclusion supported by mathematic modeling of changes in BCR-ABL transcript numbers in responding patients. Whether this is clinically relevant remains to be seen. In summary, responding patients should continue IM indefinitely until such time as the results of prospective studies suggest otherwise." Negative PCRs for over 2 years is the criteria used for the study discussed above. Also, the patients who did not relapse in the study had taken Interferon-alfa before Gleevec. It is unknown whether that had anything to do with it. But this has caused a renewed interest in Interferon combined with Gleevec, and clinical trials are underway on this. Since Gleevec is not a cure, why have some remained disease free after stopping Gleevec? This is an interesting question, and no one knows why. There is debate about which level of stem cell causes CML. Some types of stem cells die after a number of years, and some live as long as the person does. If a person with CML can outlive the stem cell that originally caused the CML, then a cure could result, because all the leukemic daughter cells would eventually die and would not be replaced. While Gleevec does not seem to cause an actual cure, it could possibly allow a person to outlive the originating leukemic stem cell. If this theory is accurate (and no one knows), some who are PCRU could actually be cured and not know it unless they stop therapy. As I see it, there will be clinical trials that include stopping drug therapy, and these will provide information that will allow an informed decision to stop treatment. Until then, the recommended approach is to continue, and especially if a person is not PCR undetectable for at least 2 years. It is unusual that an Onc would suggest stopping Gleevec. But I will admit that it would be tempting to stop after being PCRU for many years and see what happens. But if someone is going to do it, continuous PCRs would be needed, probably monthly. But this information is one more reason to have hope that we might not need to stay on drug therapy for the rest of our lives, because a cure for CML -- in one form or another -- might be possible some day. --~--~---------~--~----~------------~-------~--~----~ [CMLHope] A support group of http://cmlhope.com ------------------------------------------------- You received this message because you are subscribed to the Google Groups "CMLHope" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/CMLHope -~----------~----~----~----~------~----~------~--~---
