The important thing is I think the specificity of this compound is really well-tolerated, and I think that is going to be important when we get to the market because we are going to be there without having a lot of data in patients, so the safety profiles I think are just going to be very, very important for its adoption. This is what we announced last Friday, that the results of the ANNEXA-R, which is the reversal of rivaroxaban with the bolus only, so the short duration, was very consistent. We met all the primary efficacy endpoints, met all the secondary endpoints, high statistical significance and again, welltolerated, no SAEs, important antibodies to factor X or factor Xa. One of those things we continue to watch, if you say, where is the Achilles heel maybe. These are the things we continue to watch.Thus far, we have got a pretty good profile. I am not going to say anything more because the results are going to be presented in oral presentation at the American College of Cardiology.
Here is what we announced today and that is the design and the start of our ongoing confirmatory clinical trial. This was a significant effort. The accelerated approval, we are doing something unprecedented here. We think we are doing something unprecedented with betrixaban based on the biomarker approach and the statistical analysis approach, but we are really doing something unique and groundbreaking here. It will be an accelerated approval, as we said, based on the PD data from the Phrase 3 trials and healthy volunteers and then the confirmatory trial of that is ongoing. That is the package that we agreed to with the FDA. They said, “Send us greater than 10 patients’ worth of data from this trial along with your healthy volunteer studies for approval.” That is what we intend to do.
What if it is a single-arm study, we are not required to randomize patients which we did not think was ethical and we did not think it was possible. After hard work with the FDA, they agreed. That 270 patients that are treated with a factor Xa inhibitor and come to the hospital and are admitted for major bleed. That is who these patients are. There are certain exclusion criteria. We have a co-primary endpoint, the same primary endpoint that we had in de facto Phase 2 and Phase 3 that is factor Xa levels and then the achievement of effective hemostasis. We are going publish with just what that means.
What I will tell you is this, the faster you get hemostasis, the more effective we are going to define the hemostasis. What we are trying to do is get a certain percentage of patients that all have what we call effective hemostasis. It is compared versus a historical control from the antidote, or I should say, reversal agent that is used for Warfarin. We will study during this kind of first 12-hour period and then we will do a 45-day safety followup.
I think it is important to start, we are hearing a lot about who the competition is. They are behind us but we are hearing a lot of about who they are. We are starting to define who we are versus who they are. Right now, you have andexanet which is a recombinant protein. You have a small molecule inhibitor called PER977. We are unclear of its mechanism of action. Then you have 4-Factor PCCs. These are the factor II, VII, IX and X factor replacements that are approved for warfarin, but not currently being studied in a pivotal way for factor Xa inhibitors.
All I am going to say about this slide is we are going to start to spend more time here. There are five factors that we discussed with the parameters. We discussed with the FDA to give us an accelerated approval, made them comfortable approving a drug based on healthy volunteer in an accelerated way. That is understanding of the mechanism of action. That is a clear activity against PD markers that are validated, anti-factor Xa units, normalization of thrombin generation, discussion on the half-life and adverse events. These are the five parameters that we discussed with the FDA to come up with a package for accelerated approval.
