NorthWest Biotherapeutics Inc (NWBO)

[meirluc]

While Leprecon's recent analysis is very interesting, his estimate of only 55 survivors during October 2018 (one month prior to the SNO update) is too pessimistic IMO. During March 2017 there were 108 survivors. If only 55 remained alive during October 2018, 19 months later, it would imply that as many as 53 events occurred during the 19 months (March 2017-October 2018), or (2.8 events per month). That would be a very high attrition rate during that period of the trial.

Most of the patients still alive during October 2018 originated from the last 1/3 of the trial (about 108 patients) and that group contributed about 42 post 36 months survivors.

Most of those 42 would most likely still be alive during October 2018 because at that time they would only have been only about 37-49 months on trial with most of them much closer to 40 months on trial.
Perhaps of the 42 post 36 month survivors, a minimum of 36 (83%) survived during October 2018.

Of the 28.2% post 36 months survivors (about 93 patients), there were in addition to the 42 just mentioned another 51 who previously had survived 36 months on trial. If only 55 patients were alive during October 2018 and about 36 originated from the 42 later enrolled patients, then only 19 would originate from the earlier enrolled 51 post 36 months survivors.

The 2018 JTM publication estimated the mOS of post 36 months survivors to be 88.2 months. It is therefore highly unlikely that only 19 of the 51 (37%) of the earlier enrolled long livers were alive during October 2018 especially since most of the 51 were at that time only 50-70 months on trial. Instead I am estimating that during October 2018 at least 30 of the earlier 51 who survived past 36 months were still alive during October 2018.

With 30 of the earlier group and 36 of the later group alive during October 2018, we would have a total of 66 in lieu of Leprecon's 55 October 2018 survivors.