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marzan

03/04/17 5:17 PM

#105922 RE: Doc logic #105920

One more thing to add is if the trial is futile, how comes the combo trial with BMY is just about to start in April? Why is interested in it? why FDA is allowing it?
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biosectinvestor

03/04/17 7:52 PM

#105936 RE: Doc logic #105920

Thanks, Doc. Agreed.

AVII says all sorts of things. Sometimes it's that the treatment might work, but it's just because of a very particular twist in the protocol, or because the ultimate number is not adequate. I don't think these are determinative because if they were, it would not be a secret and I don't think the company could hide it if they knew, from the regulators. More importantly, though, as I've said, I think other factual checkpoints suggest other possible conclusions.

I agree that while AVII says that the entire enterprise is a fraud, on some occasions on other occasions, to sound reasonable, he says well, maybe it works, but it can't be proven. My belief is he really has no idea, and the mere constant, active discussion of futility is valuable to some alone. The evidence is not really the purpose of these discussions, it is to get people to step back and not make any determination with any conviction of their own, with the constant refrain that people just don't want to hear them, and people are closed minded.

I don't think that's the case. But I do think the daily, incredible degree of constant speculation based upon very tenuous indicators, not even hard evidence seems to be very useful in doing a steady bit of damage, every day.

They could ultimately be right in the ultimate outcome. Maybe it doesn't work. But the speculation by persons who admit they own no shares, on a daily basis, for years on end, day, after day, after day, hour after hour, after hour, is always a reason for concern.

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AVII77

03/05/17 8:09 AM

#105969 RE: Doc logic #105920

The reason patients agree to join trials in the first place is to have the opportunity to perhaps receive a better treatment than SOC. As AVII77 says, futility does not necessarily mean that the treatment does not work but I believe that regulators want patients to always have the right to know, at the earliest appropriate time, what the futility situation is so that they can make their own best informed choice. I believe that clinical trial guidelines specifically point to this and that this is the most ethical way to proceed.



I generally agree with what you say above with the exception of the bolded "futility situation".

One reason these DSMB's are constituted is because they are composed of members with the scientific and statistical background to understand the nature of evolving data. They are supposed to be impartial and unbiased. One of their roles is to sort of enforce a Ulysses Contract; tying the researchers to the mast to resist the sirens song of promising (but not conclusive) data as the trial evolves (Sorry, I love that analogy, it's not mine but I don't remember where I got it).

It is only if overwhelming early data (positive or negative) is seen that they can "untie" the trial before its' conclusion.

And they use statistical tests to guide them (they are not bound by the tests, they evaluate everything in context).

So, I prepared the figure below (from the SPRINT trial investigating aggressive BP lowering) for something else but further edited it for this discussion (all the colored text is mine overlain on a figure from the paper buried in a supplemental appendix).

It shows the stopping boundaries for the trial along with results from the first 5 interim analysis's. The trial stopped at the 5th interim (it crossed above the efficacy boundary).

I also sketched in blue a hypothetical futility boundary. Notice it asymptotically approaches the efficacy boundary at further time points (100% information fraction=100% expected events).

If they were to do an interim with just 5 more events still to acrue, it had better be damn close to p=0.05 because if it's not, the chances of those 5 events bringing it better than 0.05 is very small. Conversely, earlier in the trial the futility boundary is close to the what I labelled the "harm" boundary which is the line below which Placebo is convincingly better.

I ask you:

What would you do if you were on the DSMB and saw results as shown with the red dot (and green arrow)?

I would also ask you: what would you do if the red dot was below the 0 line (not conclusive "harm", just placebo "trending" better) and you also saw the OS data trending positive?

Would your knowledge of response dynamics in immunotherapies affect your decision considering the endpoint is PFS?

These are serious questions intended to illuminate my theory here and I hope you give it some thought.