The key is whether the formulation can be modified in such a way...

The key is whether the formulation can be modified in such a way to deliver the drug to the target cells in the nasal passages. Safety should not be an issue. It's only known side effect is as a weak anti-coagulant. But there may also be a concentration at which it is cost prohibitive/no longer competitive with steroid based nasal sprays.Was any field testing done before moving to a P2 hayfever trial?

The next two trials are different in that there is strong evidence of effect from others that have been using PPS....these P2 trials will most likely (hopefully?) show that is the case. Then longer P3 trials around long term use, frequency, both in treatment length and gaps between courses to work out maximum patient benefit