Hey Hip, I had severe OI, with NMH and POTS for 5 years before the Tx. I was unable to stay in an upright position for more than a few minutes at a time without severe worsening of those symptoms. There is no doubt that it was the Cidofavir Tx. that eliminated the OI. I'm not sure why that particular symptom had resolved, but it seems to me that we had hit a CNS infection that was causing much of my symptoms. I have no idea if that particular symptom was resolved for others on that Tx. I didn't inquire on those particulars with others, or with the doc. I only know that many got better. I think the most common response are those like myself....partial responders.