Sunday, December 12, 2010

Asymptotes and secondary cancer...

It's been a pretty busy couple of weeks here.  At my office I have three half-written posts that never got finished!

The first of these has to do with tying the previous post (about the efficacy of tandem transplants) more concretely to what Arkansas is doing.  The study that demonstrated this was not a UAMS study.  And it was done without the benefit of any new drugs -- BB uses tandem transplants plus the most potent induction protocol there is, plus Velcade and Revlimid.  The efficacy of Total Therapy, therefore, is probably higher than the data would suggest.

But the real takeaway from that data is the notion of a plateau.  UAMS' philosophy is predicated on the idea that if somebody has not lost remission by year X, they are cured.  This was seen in a type of childhood leukemia as that disease was treated in a manner similar to Total Therapy, and that disease is now 95% curable.

People pooh-pooh the notion of a plateau in Myeloma, but I've never seen anybody explain why.  This includes my maintenance doctor who seemingly doesn't understand the statistical notion of an asymptote (this explains why I never finished the other post...I wanted to bring some graphs into this and perhaps in a post to come I shall).  At the highest level, an asymptote in this context means that instead of the chance of recurrence being equal or random over time, it grows smaller as remission is sustained and eventually disappears.  In the study below (from memory) this was noted at 11 years.  Which is about where UAMS noted it at the time of Total Therapy 1 (pre Velcade and Revlimid and Thalidomide).  UAMS is now in Total Therapy 4 and 5 for newly diagnosed low- and high-risk patients, respectively, and the plateau for low-risk appears to be at three years post-complete remission.  That means that if one makes it three years, one can go off meds and know that they are very likely cured (95% or more likelihood).

This brings me to the other issue in this post.  Revlimid.  Now key to any treatment of the disease, and an integral part of maintenance therapy for me and others treated at UAMS and elsewhere.  Last week, Celgene (makers of Revlimid) took a pounding in the stock market when data suggested that their drug causes secondary cancers, such as Acute Myelogenous Leukemia.

This, needless to say, is jarring.

The exact statistics are a little vague at this point and no dosing information is available, and whatever secondary cancers show up are probably not as bad as contending with the mortality rate from untreated Myeloma.  But I still don't like it.  Particularly because (although there is no specific data that I could find) it is suggested that the occurrence of secondary cancer increases significantly when one has a stem cell transplant.

The best longitudinal (i.e. over time) data on the use of Revlimid, of course, comes from UAMS where BB has been using it for around seven years.  That is actually three years longer than the study that was completed that indicated the secondary cancer.

So I emailed UAMS to ask them to share their own statistics with me.  They will have tracked hundreds of people under their protocol and they'll know how many, if any, have contracted secondary cancer.

I've not heard back yet...which means I may go directly to BB himself.

I'll be there next month anyway, so I will find the answer.

In the meantime...I look a little more askance at each blue-and-white pill that I take in the evenings.  It's a little disturbing...