A new chemical entity, NKTR-181, is the first full mu-opioid agonist analgesic. The treatment is designed to be a potent pain reliever without the high levels of euphoria that may occur in patients taking standard opioids. As a result, NKTR-181 has been granted a fast track designation for treating moderate to severe, chronic pain by the U.S. Food and Drug Administration (FDA).1
In the recent Phase 3 SUMMIT-07 trial, twice-daily NKTR-181 tablets were compared with placebo for treating opioid-naive patients with moderate to severe chronic low back pain.2 The study’s participants (N=610) were 18–75 years of age and had moderate to severe non-neuropathic, chronic low back pain for at least six months. An open-label, dose-titration period was followed by a randomized, double-blind, placebo-controlled, 12-week treatment period. During the open-label titration phase, patients with a pain score between 5 and 9 were titrated to twice-daily NKTR-181 until they had an adequate and sustained pain response, which was defined as at least a two-point drop and a pain score below 4 on the numeric rating scale (NRS) of 0–10. These patients were then randomized (1:1) to continue receiving NKTR-181 at the same dose or to receive placebo (i.e., the active drug was withdrawn) during the 12-week treatment period. The primary efficacy endpoint of significantly reducing chronic back pain vs. placebo was met.
