New Opioid Relieves Pain Without the ‘High’

By Pat Anson, Editor

Nektar Therapeutics has announced positive results from Phase III study showing that a new opioid medication significantly reduces pain without the high levels of euphoria that can lead to abuse and addiction.

The company also said the Food and Drug Administration has given the medication – known as NKTR-181 – “fast track” designation for the treatment of moderate to severe chronic pain, a status that allows for an expedited review of the drug.

Many pain sufferers say they do not get "high" or experience euphoria from opioid pain medication. But drug makers and government regulators are seeking to develop painkillers with less risk of abuse and addiction.  

"The data from this efficacy study are extremely important because they demonstrate that NKTR-181 produces strong analgesia in patients suffering from chronic pain while NKTR-181 has also demonstrated significantly lower abuse potential than oxycodone in a human abuse potential study," said clinical investigator Martin Hale, MD, medical director of Gold Coast Research.

"While standard opioid analgesics, including abuse-deterrent formulations, have been the most effective way to treat chronic pain, they are associated with serious safety concerns and many opioid-naïve patients fear taking them because of the potential for abuse and addiction.  The data for NKTR-181 suggest that it is a transformational pain medicine that could fundamentally change how we treat patients with chronic pain conditions."

The placebo controlled study involved 610 patients with moderate to severe chronic low back pain who had not taken opioids before. During the open-label phase of the study, pain scores dropped by an average of 65% in patients taking NKTR-181 twice daily.

The company said over half the patients (51.5%) on NKTR-181 reported their general overall status and quality of life "improved" or "very much improved" compared to patients taking a placebo. 

They also reported better overall quality of sleep, with less sleep disturbance and fewer sleep problems. There were no differences in daytime sleepiness on NKTR-181 versus placebo. The drug was generally well-tolerated, although some patients reported nausea, constipation and somnolence.

Nektar is currently conducting another Phase III study to evaluate the safety and tolerability of NKTR-181 in 638 patients with chronic low back pain or chronic non-cancer pain.

The company says NKTR-181 is the first opioid molecule to provide pain relief without high levels of euphoria and sedation. The molecular structure of NKTR-181 is designed to have low permeability across the blood-brain barrier in order to slow its rate of entry into the brain.

Nektar is a research-based biopharmaceutical company that discovers and develops new drugs for which there is a high unmet medical need. It has a pipeline of new investigational drugs to treat cancer, auto-immune disease and chronic pain.