Hi Lynn,
maybe you remember me, we have contacted three or four times in the mds-foundation.org's forum about two years ago.
Didn't you work with dogs...?
It is absolutely wonderful, that your response to VPA is so long-lasting!!! 
To confirm Lynn's experience with VPA:
My doctor had told me with a trisomy 8 I probably could be lucky and I was.
In 2008/09 I took Valproic acid (it is a traditional drug against epileptical attacks) and I responded to it for almost 10 months. I was transfusion-free, what a gorgeous experience. The drug kept my HGB between 9 and 10.
But then it slowly stopped working and my HGB went back to 8.
My physician tried to increase the dosage, but unfortunately the response was over...
Like you, Lynn, I gained some weight (14 lbs !!!) during that time. Once I stopped to take the drug, it fell off me within a couple of weeks.
In the beginning of the therapy I used to be very tired, but this side-effect disappeared after two weeks.
What dosage do you take, Lynn?
So, for some MDS-patients VPA seems to be a "harmless option" for some time.
Greetings, Bergit