The data reflect the percentage of patients whose test results were considered positive for
antibodies to adalimumab in an ELISA assay, and are highly dependent on the sensitivity
and specificity of the assay. Additionally the observed incidence of antibody positivity in
an assay may be influenced by several factors including sample handling, timing of
sample collection, concomitant medications, and underlying disease. For these reasons,
comparison of the incidence of antibodies to adalimumab with the incidence of antibodies
to other products may be misleading.
I've been asked, recently, what the high percentage of antibody responses meant in the MEDI-507 trials.
What this paragraph (above) says is that those who are performing the assay can set stringency, such that they can get any answer they like. Here we have Abbott discussing a modest frequency of response -- including neutralizing antibodies -- for a drug that just garnered expeditious handling at FDA. Previously, we had MEDI reporting a higher frequency of non-neutralizing antibodies for a product which they (IMO) botched in phase II.
My best guess? Abbott sets stringency high, Dr. Young sets it low and lucks out, getting FluMist as a diversion.
It's my opinion that a good serologist can get the answers that he, she or Marketing needs/wants. I'll bet that Abbott is working in a high concentration of normal human serum with lots of warm washes, and that the illustrious Dr. Young chose cold PBS and little concern for washing, period.
For any MAb that I've looked at, human (EBV transformant-derived) or murine, I've found titers in EVERY normal (never received any passive antibody product) human. You want me to produce data that, in table format, makes a competitor's product look bad? No sweat. You want me to find assay conditions that will favor hiding one set of low-titer anti-id reactions but which will leave anti-id detectable for a second? Piece of cake. Etc. |
