Thursday, January 10, 2013

ASH 2012: Dr. Pagel discusses transplants for CLL and the Role of Radioimmunotherapy

In the final short segment of my ASH 2012 interview with Dr. John Pagel, he discusses the approach to hematopoietic stem cell transplants (HSCT) or what were once only bone marrow marrow transplants in CLL. Now, we more often harvest the primitive blood stem cells from the peripheral blood after they have been mobilized. Much easier for the donor who doesn't need multiple bone marrow aspirations.

What Dr. Pagel talks about the real possibility of cure for some patients, especially those who go in to transplant with their disease in a deep remission.

The news is that using a drug such as Zevalin (ibritumomab tiuxetan), a radioimmunotherapy (a radiolabeled monoclonal antibody) or RIT in high doses is getting the necessary deep remissions and improving the odds of that cure. Ibritumomab is similar to rituximab in that it latches onto and destroys any and all CD 20+ B cells (cancerous or not), but it differs in that it carries a radioactive payload to those cells and thus destroys not just the cell, but its nearby homeys. This is especially helpful in shrinking bulky cancerous nodes, but can be dangerous if there are too many B cells left in the marrow as the local radiation delivered can cause lingering damage to the future home of the new donor stem cells. Still, it is a lower dose, more "surgical" way in many settings to get the radiation precisely  to the desired sites (at the cellular level) than is an external ionizing radiation source, no matter how focused. And most CLL, at least to start out, is exquisitely sensitive to radiation, although it always come back, and often comes back meaner. 

There are significant expense and turf issues in the medical world that explain why RIT is a very much underused therapy. Briefly, it is very costly per treatment, but is usually used only once or sometimes twice, so the total cost is comparable to a full course of say FCR. More tricky is the role of the doctors administrating it. It can mean transfer of care from the medical to the radiation oncologist and many doctors are loathe to give up control of their patients. We can argue that it needs the services of both a medical and radiation oncologist and their support teams of pharmacists, nurses, and technicians. More turf issues.

But I digress. RIT is a great choice if we need a transplant and we can get buy in from our doctors and insurance.

And the other news is that the mortality curve seems to plateau around 3, not 5 years. After 3 years, we stop relapsing. The CLL doesn't come back.

In other words, if we can make it three years out with no evidence of the cancer returning, we can be pretty confident that we are, dare I say it, cured.

Transplants are risky business, but are a sensible option for those who are young with aggressive disease, who may not have the time or the option to wait for one of the new magic pills. And they can absolutely be curative.

You can't say that about any other CLL therapy. At least not yet.

Here is Dr. Pagel. Enjoy.

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Blogger Unknown said...

not cool how close the name is to ibrutanib. It's like they do it on purpose.
This radiation thing sounds scary to me. Interesting though

January 10, 2013 at 7:34 PM  
Blogger debinoz said...

Thanks Brian - interesting - I'll ask my prospective transplanter about this when I see him in a couple of weeks.

May 17, 2015 at 9:57 PM  

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