Seres Therapeutics Inc (MCRB)

[Digger 2-0]

Seres Therapeutics (NASDAQ:MCRB) Postulation

I awoke today to something I absolutely did not expect - the report of Seres Therapeutics down over 70% on bad "surprise" data. It didn't make sense.

How can you have Phase I data that showed 96.7% (29 of 30) of the patients achieving clinical resolution by week 8 and Phase II data that showed no difference between placebo:

Based on 8-week data, CDI recurrence occurred in 44% of subjects (26 of 59) who received SER-109, compared to 53% of subjects (16 of 30) who received placebo.

Statistically, this just screams impossible. Something must be different in their methodology, otherwise this is a statistical anomaly.

So I dug. The Phase I trial design is not on clinicaltrials.gov, but you can find it here. There are some interesting things in the methods, but let me highlight these points:

http://seekingalpha.com/article/3993931-seres-therapeutics-matter-details