If these three individuals who responded to the CLL vaccine treatment are cured, then so are many of us on this CML Board (but we know that is not accurate). The NEJM report (the more detailed story) says that the CLL study participants became cytogenetically negative. In other words, the BMB was clean. But as we know, that does not mean the PCR would be undetectable. And even if it was, that still does not mean "cured". However, the news story is somewhat interesting if put into its proper context.
I will re-post here my response to this issue from another thread:
To summarize what the article is discussing, it is discussing a type of leukemia vaccine. The term "vaccine" can be confusing when used in this context, since a vaccine is normally used to prevent a disease from occurring, such as a flu vaccine. A leukemia vaccine would be given to someone who already has the disease, to control or possibly even eliminate the disease. There are several different leukemia vaccines currently being tested.
In general terms, the leukemia vaccine trials are trying to stimulate the body's own immune system T-Cells to mount a battle against leukemic cells. Leukemic cells look mostly normal to the body's immune system, so they are generally left alone. But leukemic cells are actually different than normal cells in some important ways, besides just being malignant. They have subtle variations that make them actually look slightly different, although not normally different enough to trigger attacks from the T-Cells. So a vaccine would teach the immune system to recognize that the leukemic cells are different, since they have greater amounts of certain substances in the cells. The theory is that if you can teach the body's T-Cells to recognize the leukemic cells as abnormal, including the leukemic stem cells, the immune system would see them as a target and kill them. And since the leukemic stem cells are the source of all other leukemic cells in the body, killing them would be like cutting the head off the snake. But even if it did not kill the stem cells, a vaccine could be used to control the disease much as Gleevec and Sprycel kill the leukemic offspring cells, but not the stem cells that produce them. Remember that this is mostly theory and not yet proven as actually possible, although there is some evidence so far that the theory works to some degree on some people.
There are various types of vaccine trials ongoing around the country. Some involve a peptide "marker" called PR1, others involve WT1, and some use a person's own leukemia cells that have been irradiated. So theoretically, the leukemic cells are different enough that the body's immune system could be taught to recognize those differences and respond. As previously discussed, leukemic cells look very much like regular cells, so they are not normally attacked by the immune system's T-Cells. Each type of T-Cell is specific to certain invaders. A polio vaccine teaches the body to make T-Cells to fight anything that looks like a polio virus, and the effects last for a lifetime. That is the theory of a leukemia vaccine, except that it is given to someone who already has leukemia to control or eliminate it. So a leukemia vaccine could be a cure, not used for prevention.
Now, regarding the article cited above, this is discussing a very novel leukemia vaccine approach that turns patient T-Cells into something called "chimeric antigen-receptor T cells". In trying to explain this in understandable terms I will need to make an imperfect analogy. This generally means that some of the body's T-Cells are changed so they grow new external "antenna" that are highly attracted to leukemic cells, and they also grow new "docking ports" that match the leukemic cells external "shapes" (remember this is an imperfect analogy). After "docking" with the leukemic cell, it is destroyed. Sounds wonderful, and it could work in some cases. But there are issues that need to be overcome. These genetically engineered "antenna" and "docking ports" (wish I could do better, but let's stick with that) can sometimes also attract and kill non-leukemic cells that look like leukemic cell docking shapes. So in teaching the T-Cells to kill something new like leukemic cells (yippee) they have also been taught to kill good stuff like, oh, let's say organ cells (boooo hisssss double bovine sharts). I am speaking in general terms here, not about this specific CLL issue in the article. But if you read the NEJM article associated with the main article, this issue is pointed out as something that has happened previously when trying to use "chimeric antigen-receptor T cells". So it takes some hard work to eliminate the toxicity of things like this so they only attack what you want them to attack. But what else is new. That is how progress is made.
So far the study looks like it has merit. But there is much work to do.
A cure for CML will come along some day in the relatively near future.
Here are some links to general info on leukemia vaccine research: