NorthWest Biotherapeutics Inc (NWBO)

[meirluc]

vator, it is hard to know whether the success of the last 108 was due to an improvement in formulation of the vaccine but that seems to be a reasonable explanation. It is possible that the last 108 were just lucky but it is hard to explain the great differences between the last 108 and the previous 223 just on the basis of luck.

The first 223 had at most 51 (44+7) or 22.9% post 36 months survivors whereas the last 108 had at least 42 of 108 (38.9%) in the same boat.
What is interesting is that at 3/17 the 2 year survival of all 331 patients was 46.2% and at 10/18 it was 46.4%. That means that the approximately 40 patients who were alive at 3/17 but were only 18-24 months on trial demonstrated only a slightly higher 2 year survival percentage than did the earlier enrolled 291 patients. I don't know how many of the last 108 were patients who at 3/17 were enrolled 24-30 months on trial but the enrollment curve slope does not suggest a substantial numerical difference between the numbers enrolled at 3/17 between 18-24 months and those enrolled 24-30 months. Assuming that 50-54 of the 108 were enrolled at 24-30 months, the 22 of that group surviving 24-30 months at 3/17 (average perhaps 27 months), do not suggest a greater than 50-55% survival at 24 months.

Even with a 50% survival at 24 months for the last 108, a post 36 months survival of 38.9% shows that after 24 months on trial, the attrition rate for that last group decreased dramatically. Contrast that with the attrition rate of the first 223 patients: 46% alive at 2 years, 22.9% alive at 3 years. I don't believe that these differences can be attributed only to statistical fluctuations, luck, etc. When the final results come out we will probably know much more.