Their report says a very recent change in the trials end point and protocol to add an easier objective may give an advantage to placebo and make the trials endpoint actually statistically harder to achieve. That and forseeable competition from another company (starts with an "S") with a similar product entering Phase III could limit upside NT even with good results.
Says trial risks are now increased. 50% decline if results do not meet stat significance so more cautious... Still maintain longer term buy opinion though.