Saturday, December 24, 2011

Doing well after my second round of bendamustine/rituximab

I am now almost 3 weeks from my second round of bendamustine/rituximab (BR) and am happy to report good progress. At the beginning of treatment I had very large lymph nodes and a WBC of 75K. My nodes shrank considerably after the first round and some more after the second. My WBC has gotten as low as 2.9K (fortunately with the help of Neulasta half of those WBC are neutrophils). I have had side effects though, as expected, as platelets got as low as 20K (got one platelet transfusion) and anemia with hemoglobin to 6.2 twice (got transfusions of packed RBCs twice).

I had shaking chills without fever and then fever during my Rituxan infusion on the second cycle, despite stopping the infusion, giving steroids and Benadryl, I only got 1/3 of the whole Rituxan dose. This was odd as I have had Rituxan many times before without effect. But it is possible to have an allergic reaction any time from the second to the one millionth exposure (this is what I often told my patient's parents when they developed drug allergy after tolerating their amoxicillin many times before). With these complicated biological molecules there may even be an infusion reaction on the very first exposure, the molecule somehow setting off a cytokine storm of sorts. My wife, a recent nursing school grad (yay! congrats over and over!) and I speculated while I was recovering from the shakes that maybe there was an antibody against mice protein in the packed RBC I had gotten a week and a half prior. Packed RBCs have a small amount of plasma and this could contain antibodies or antibody-antigen complexes (for example see http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/BloodSafety/ucm095556.htm). If there were antibodies against mouse protein that could explain my reaction, in that rituximab is a chimeric mouse-human protein.

The fever persisted after treatment and even though I had 1.4K neutrophils I was admitted for several days for observation and antibiotics. The fever subsided by day 2 after last Bendamustine and 3 days afte aborted Rituximab. The plan for next round of BR is to preload me with steroids and antihistamines. Here's hoping I don't have to go through the fever part again.

My hemoglobin has run between 8.4 and 7.7 after the second transfusion, and since I am in good cardiovascular shape, having trained for a half marathon this summer, I can tolerate this level, getting a bit winded only when going up hill with my dogs or doing a few staircases. That said, my oncologist is contemplating starting me on erythropoietin to get my hemoglobin up into a more tolerable range.

I will continue to post on my experience, and maybe even a semi-scholarly exposition on bendamustine since I have a week and a half off from my job with the Christmas holidays...

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