2nd Round of ATG---Horse vs Rabbit???

[NLJabbari]

My 19 y-o son received a first round of ATG(horse) back in 2004. He was in remission for a while, but since then has relapsed. The doctors found (2) 9/10 MUD's but we've decided to try another round of ATG instead. The problem is that 6 months ago when he relapsed, he also was transferred to "Adult Medicine"...His "NEW" adult Hemo/Onc Dr. had initially recommended "Rabbit ATG" instead of horse, but most recently has decided that perhaps "Horse" would be a better choice bc of new medical-reports stating that "horse ATG" is better. I am so confused and would like to hear what others thoughts on this may be.

BTW, since his relapse his WBC is good 7.1, his platelets around 80-90K, but his Hgb falls into the 7 range and is currently requiring 1Unit of PRBC's monthly.

Thanks, would appreciate any feedback regarding this.

[Neil Cuadra]

Norma,

I think you, Yashar, and Yashar's doctor are on the right track. Yashar got a long remission from ATG last time so I can see the advantage of another round compared with a transplant. Yashar's age makes him a good candidate for either treatment, but ATG is less risky.

Medical thinking about the horse/rabbit choice has evolved since 2004. It used to be pretty automatic to use horse in the U.S. and rabbit in Europe. Then doctors in the U.S. started using rabbit when giving repeated ATG to some patients who had had horse the first time. But head-to-head studies have now shown that horse has a statistically better success rate. Maybe I'm overgeneralizing but that's how I've interpreted what I've read.

Yashar's doctor is probably looking at the latest research and considering how it applies to the particulars of Yashar's aplastic anemia, just as he or she should.

I really wish that you, Yashar, and your family didn't have to deal with a relapse and go through more treatments, but it's not uncommon for a second round of ATG to be just as successful or even more successful than the original ATG.

[ssdavi71416]

The link below is an Article by Young and Scheinberg.

http://bloodjournal.hematologylibrar...1185.full.html

The article is titled "HowI Treat Aquired AA"

There is also a recent article from May that discusses the differences in treatment using Horse Vs Rabbit

http://www.medpagetoday.com/Hematolo...y/Anemia/27904

[NLJabbari]

Thanks for the feedback and the links to these great articles. They are long and I will sit down and study this information. I may discuss this with Yashar's doctor.

[amberb]

It was my understanding that when repeating ATG you had to alternate horse and rabbit. Whichever you had the first time, you did the other the second round.
I personally had Horse ATG in 7/11, then Rabbit ATG 1/12 after having no improvement with the first treatment. For me, the rabbit treatment was much easier and had fewer side effects than with the horse.
Good luck to you on your son's future treatments.

[aplasticgirl]

After horse ATG and no response it was repeated (horse ATG) a year later. I did respond and have been in remission (still on low dose cyclo) for 13 years.

[Hopeful]

I was told that it is perceived that the risk of serious reactions during the administration of the ATG (i.e. anaphylaxis shock) was greater if the same serum was repeated. That is why they alternate horse-rabbit. There hasn't been a clinical trial to prove or disprove this, but it is the perception.

[Lisa V]

Norma, if the best match they've found for Yashar is 9/10, I'd go with ATG again, and I'd go with horse. You can keep the rabbit in reserve in case the horse doesn't work. From what I've heard, going back to horse after you've done rabbit is not advised, I'm not sure why. Going the other way seems to be okay, but as Neil says, recent evidence seems to point to horse as the more effective treatment.

Ken's ATGs were both horse. At the time I too thought it was customary to switch to rabbit for the second round, but our doctor said that since he'd had a response to horse the first time, it's likely he would again. His relapse didn't have anything to do with the horse serum's effectiveness, it was a taper issue. The second round worked fine, in fact better than the first. We were armed with all of the trials and errors from the first round and able to make some better treatment decisions the second time.

Also, based on a consult, the doctor increased his infusions from 5 days the first time to 10 days for the repeat, and said that if we ever had to do it again, it should be for an even longer period, say 15 days. We have a new doctor now, and neither he nor I have been able to find any information to supports this practice, but it worked out well for him.