I think the market is right. Aducanumab was a mistake on the FDA's part and they should not have gone against such a one sided AdBoard vote (its. not like was 5 for to 6 against it was 1 for and 10 against). They did two large phase 3, one barely succeeding and the other a clear failure. This has caused more problems than the approval fixed. Lecanemab has a large fhase 2 and the very large phase 3 without a large phase 3 failure. Plus their data looks better than the one successful aducanumab trial. The problem with A273 is that it looks like the main cognitive data did not pass the one sided 0.25 (or two sided 0.05) threshold. And that was with a very liberal modified ITT first ignoring patients unable to get titrated to enter the maintenance phase and then excluding patients who did not have a 48 week measure . We don't even know the ADCS-ADL mean change. The 2b/3 looks like a 2b.
Was the pooled data the pre-specified cohort in the SAP? If so, the analysis to date is ok to present as the cohort though insufficient for an NDA (IMO) (due to one sided > 0.025 and lack of co-primary ADCS-ADL mean change data). If instead 50 vs placebo and 30 mg vs placebo was the primary endpoint pre-specified endpoint then we have no data to offer an educated opinion as dose breakdown data is missing (missing for us, Missling has had it concurrent with receiving the initial analysis --- you don't not get the primary data)
Did the SAP designate the definition of modified ITT to be those who completed the study (both baseline and 48 week data). Highly unlikely IMO as modified ITT for most studies like this one will have the modified ITT group those in the ITT who took at least one dose and had at least one post dose clinical evaluation). I do not think baseline and 48 weeks were the only clinical testing days.
Why was n not included in the clinical endpoint slides? Why was 0.5 point chosen as a clinical meaningful improvement for ADAS-Cog when a change so low is not meaningful. Was any sensitivity analysis done with other thresholds (the answer is of course as it is standard, but what were the results)
So I put the likelihood at near zero. I do think you came up with possibilities that together add up to the 1-2% chance that I give for AA
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