Although the hurdle rate for the first interim report is very high, i.e. a P value of .004 or 99.6% degree of confidence that the test is just not lucky a low P value, although not hitting the target, will still be very favorable. Close is very good. Basically 90% of the patients will need to survive 1 year. The next interim report has a P value of .019 or 98.1% degree of confidence. The final target at the end has a P value of .043 or 95.7% degree of confidence. You can drive the P value through the size of improvement over standard therapy and by the number of patients.
In addition, the IMPRESS patients will be getting the 300 million vaccine for 12 months instead of 6 months. One might expect to this to be a better treatment because of, as of now, there has been no bad side effects. Since the trial has not been stopped we can start assuming that is still the case. Although long term side effects are not yet know, yet with this cancer they would have to be pretty bad for the treatment to fail.
A bit of speculation here, since almost immediately the trial had filled to over 50% of the patients needed for the trial one may assume that most of the patients had enrolled fairly directly. This is why with each passing day the likelihood of success continue to grow.
I could be mistaken about this but I don't believe the confidence intervals will change based on the 2 interim analysis and the final analysis. The trial is supposed to be powered for statistical significance which would be 95% confidence that the drug group is living longer, i.e. that the trial results weren't a fluke. The 1st interim is powered for 45% improvement at 222 deaths, the 2nd interim is powered for 30% improvement at 333 deaths, and the final analysis is powered for 18% improvement at 444 deaths. I'm not a statistician but I believe that all 3 of those would have the same P value.
Aco , you are correct and if the HyperAcute results follows the expected pattern in Immunotherapy of widening of the difference in the survival curve over time and unlike the chemo patients the Hyper patients should have many long term survivals / flattening of the M&K curve. Then the difference between the standard of care and the HyperAcute patients will increase / not decrease at each interim and final analysis . This is why the analysts have been so confidently predicting the trial will be stopped at the second interim analysis , because of the Immuno affect of the curve widening and the survival curve flattening over time.
I am thinking that about 90% survival is roughly what is going to be needed to get the P value of .004, which is the target for the first interim report. That's a 99.6% degree of confidence, . Hitting this target would allow them to move forward much sooner.