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Originally Posted by DanL
Greg, I have been following your post with quite a bit of interest. I too have read that Vidaza really seems to have a great effect on patients that have increased blasts - i am less than 1%, and fall into the intermediate -2 and high risk category, which is part of what concerns me - not to mention the grade 3/4 thrombocytopenia when I am already at grade 3. As for the DR15, I have not received an answer on this one yet. I did have my blood drawn for potential donor matching and asked the question, but the doctor has been out and his assistant said that she doesn't read too much of the detail in the phenotypes, so I am not sure. It does seem to be a strong predictor of success for this type of treatment - although I have also seen studies showing that up to 70% of MDS Trisomy 8 patients respond to immunosuppressive agents......this could be due to a greater concentration of the DR15 in trisomy 8 maybe?
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Dan,
It just so happened that shortly after my local doc suggested Vidaza (we had already scheduled the insertion of a port-a-cath), I participated in an AAMDS webinar that featured either Dr. Sekeres or Dr. Steensma (I forget which). I had already discovered that all the studies used to win FDA approval for Vidaza showed effectiveness in high risk patients, not lower risk folks, so I asked the webinar doc about treating low-risk patients with the drug. He said only about 25% of lower risk patients respond to Vidaza and indicated he'd first look at Revlimid, immunosuppression, or watch & wait.
We watched and waited for six months, until my increasing Trisomy 8 percentage got my transplant doc all excited and, about the same time, I found out I was HLA-DR15+. That finding sealed the deal with my local doc on immunosuppression, a therapy he had been pretty skeptical of previously. his final comment was "If you're going to do IST, you ought to do it at NIH, because they're the experts."
I don't know about the coincidence of Trisomy 8 and HLA-DR15+. If you look at the protocol for the NIH Campath trial, they have a formula for probability of response that takes into account age, HLA-DR15 status, and total number of transfusions. Dr. Olnes told me the latter hasn't really proven all that powerful a predictor, with age and HLA-DR15 the key variables. Other studies have found other factors predictive of IST response, including the presence of a PNH clone, and a hypocellular marrow. I really don't know how IST jibes with your mostly thrombocytopenic problem, but I imagine Dr. Olnes would have some data on that.
IST doesn't work for everyone, clearly. I'm not even sure it's working for me yet. One thing I wonder about your case is whether, given the fact you managed to contract PCP, you've already been pretty darned immunosuppressed. How low did you lymphocytes get? Campath takes them to zero for a month or so and knocks down the CD4s for a lot longer than that.
Let me know if I can be of use. I've got a copy of the latest article on the Campath trial if you want it, as well as a nice summary on the whole IST for MDS deal, co-authored by the late Dr. Sloand of NIH. That one has some data pulled from various studies on factors that predict IST response.
Take care!
Greg