Koo, good hypothesis and USA may be part of it.

However, I don't think that that is all of it. As a non practicing statistician my guess is the this is about both statistical and functional (clinical) significance. We kow that the team analysing the FA data was given goals or expectations that will set a bar or range of RRR at the 125 level and these criteria are used to judge if the trial should stop if it does not appear that apabetalone has a "reasonable probability" of achieving the BETonMACE goals at the end of the trial OR the trial could be altered in some way such as sample size.

On the safety side we have 4 successful DSMB reports thus it appears that safety is probably not an issue at this stage.

Therefore my guess on the statistical side is that the FA committee has some evidence that suggests at 125 (or whatever level they are at) events there is not yet strong enough evidence that the efficacy data is statistically strong. If it was strong both in terms of statistical and functional significance then the FA would proceed.

Moving to, for example, n=175, will increase the chances of statistical significance because of the bigger sample size. I do not know what level of statistical significance is required at the FA stage. If they work at the 90% confidence level (and if there is some positive effect of the drug) there is a better chance of continuation of the trial. However if they work at the 95% confidence level this is a much bigger challenge statistically speaking.

My guess, and it is purely a guess, is that the committee is not yet seeing a strong impact, hence the need for more sample. Remember, this is a 3 point MACE trial and we have not evidence to date about apabetalone and 3 point MACE.

There are many factors and this stuff is complicated beyond anything I can understand. 

I recognize my thoughts seem a bit negative but I remain long on the stock because of the post hoc findings.

GLTA

Toinv