Nektar Therapeutics has enrolled the first patient in a Phase 2 clinical study evaluating the efficacy, safety and tolerability of NKTR-181 in patients with moderate to severe chronic pain from osteoarthritis of the knee.
NKTR-181 is a mu-opioid agonist molecule which has a slow rate of entry into the brain to reduce its attractiveness as a target of abuse and to reduce other CNS-mediated side effects, such as sedation and respiratory depression.
Mt. Sinai School of Medicine anaesthesiology clinical instructor and Englewood Hospital & Medical Center pain management and palliative care director Jeffrey Gudin said NKTR-181 exhibited highly differentiated properties in its Phase 1 development, including slow penetration across the blood-brain barrier into the CNS.
"This slow rate of entry may allow us to effectively address pain while reducing some of the most troubling opioid CNS effects such as euphoria, sedation, and respiratory depression," Gudin added.
The double-blind, placebo-controlled study will randomise approximately 200 opioid-naive patients with osteoarthritis of the knee who are not getting adequate pain relief from their current non-opioid pain medication with either NKTR-181 or placebo.
The average change in a patient's pain score from baseline to the end of the double-blind, randomised treatment period is the primary endpoint of the study.
Secondary endpoints include quality-of-life assessment, sleep and motor activity scoring, as well as tolerability endpoints.
Nektar senior vice president and chief medical officer Robert Medve said, "As a new mu-opioid analgesic molecule, NKTR-181 has the potential to transform the treatment of chronic pain by using a molecular approach to reduce the risk of traditional opioid therapy while preserving its analgesic benefit."
Nektar is also considering a separate human abuse liability study, as part of Phase 2 development for the compound, to measure liking scores for NKTR-181 as compared to an active opioid in approximately 20 recreational drug users.