Zebra, RD-1 won't give us any useful analgesia data if -
1) The RD data is rendered useless due to 'procedural problems', as occurred in RD-2, or
2) If 1500 mg simply isn't a high enough dose to sufficiently prevent RD. It doesn't help us to see no/little change in analgesia if it's combined with no/little RD prevention.
So for the RD-1 results to be useful, we can't have procedural data 'mush', and at 1500 mg we have to see reasonably good RD prevention combined with reasonably good maintenance of analgesia.