Flawed statistics. I doubt 18% of the "ITP population" has even tried Tavalisse. Very few including the doctors even know it exists. It's only been out for just over a year. Who called all the ITP population or collected all their medical records to show they all tried it, and only 18% it worked? Another thing is that you don't know what you're talking about. N-Plate, Promacta, nor Tavalise have anything to do with antibodies. Tavalisse is a "SKY" inhibitor in the spleen not anything to do directly with antibodies. It's not an antibody. N-plate and Promacta boost platelet birth (production) in the bone marrow. They do not provide antibodies or have anything to do with antibodies. However, IvIg does provide antibodies all different from 1,000s of donors. That's why it's so expensive, and always in short supply. Tavalisse was invented for those that N-plate and Promacta has failed, actually. Promacta did nothing for me, N-plate was all that worked. IvIg always works for anyone, but prohibitive as long-term solution. Rituxin worked only once for me, then no response other two times. Tavalisse did not show any response in me either for a month, then it began working. My guess is that those who've even tried it (which is few), should have waited at least one month before abandoning it if they even got to try it. It's never mentioned hardly ever on here, or on the main FB group, so I know first hand with some common sense that the majority of the ITP population has not ever tried it, let alone saying only 18% responded. 18% of some group is not 18% of the "ITP population". Most of the ITP population are unfamiliar. Another crucial point is that very few ever get to try it because unless all the others have failed, their insurances will not pay for it. It's a tier 3 drug, and if anything lower tier, and/or less expensive works that has been tried will be paid by the insurance company first. So unless you're wealthy enough to pay the full price of $11k a month for it on your own, insurance will not approve it if something else older will work, etc. It's also a matter of safety. The insurance companies will pay for older drugs even if they cost the same because they have more history and predictability along with the doctors also preferring historical stability, etc. Because Tavalisse is new and expensive, the insurance companies and the doctors will shy away from it as being their first, second, or even third choice as first try with their ITP patients. In my case, everything else failed and I had nothing to lose by trying such a new drug. N-Plate worked for me, but too good my last time and nearly killed me with two arterial blood clots. So both my doctor and my insurance company agreed it was warranted to try the newest drug at high cost with the least history behind it because I was pretty much out of options, aside from Splenectomy, and that is giving up a lot of my immune system for merely a shot it would work or last. So now I get to keep my Spleen and my immune system as a normal person, and enjoying 200+ counts each blood test with no injections, and no wild fluctuations that N-Plate was giving me. Eventually if enough people demand their doctors try Tavalisse, the more we will see it discussed here and on FB, and the more accurate the statistics will be because 18% of some small group is not the full "ITP population".