The primary endpoint of the study was the sum of pain intensity differences between baseline and day 21. Nalbuphine ER (nalbuphine hydrochloride extended release) did not meet this endpoint, which the company believes was primarily due to patient dropouts in the first week of dosing.
The drug did, however, achieve a number of the secondary endpoints in the trial leading the Company to conclude that proof of concept had been established for the drug. For instance, nalbuphine ER demonstrated statistical significance in the intent-to-treat population when compared to placebo, as measured by the global assessment of pain control (p=0.006) and by the integrated assessment of pain intensity and rescue medication use (p=0.009).