morgans - eps 74.5c/share by fy2016!, page-10

They basically made a school boy error with their data collection. The trial data collected is all time dependent and they forgot to account for timezone changes and daylight saving with it so basically the FDA requested that they ensure the validity of the data as it was potentially compromised by the error.

I don't think this is anything at all to worry about. The FDA has previously said and reiterated that the drug does not have efficacy or safety issues, so you could be forgiven if you can't understand why they didn't approve it then...

As accaerics post above shows, the drug atleast in their trials has been shown to have increased efficacy without notably increased side effects. That gives me very high confidence that the drug will be approved in May, and it seems that the analysts covering QRX are similarly confident as the mean price target is ~$1.80.