Following a unanimous vote by US Food and Drug Administration (FDA) advisory committee members against recommending approval of a new opioid (oxycodegol, Nektar Therapeutics), the company has withdrawn its new drug application and announced it will make no further investment in the drug's development.

In a statement, the company expressed its disappointment in the vote as well as that of patients suffering from chronic low back pain (CLBP) and the physicians who treat these patients.

The company also said it developed the drug to help patients with CLBP and physicians, and to help mitigate the US opioid abuse epidemic. The development program for oxycodegol included over 2000 patients and volunteers.

Oxycodegol is a full mu-opioid receptor (MOR) agonist designed to have slower movement across the blood–brain barrier and a slower rate of MOR binding compared with other MOR agonists.

The drug's manufacturers claim oxycodegol has a slower onset of euphoric effects compared with other opioids and, therefore, would be less attractive as a drug of abuse.

Members of the FDA's Drug Products Advisory Committee and its Drug Safety and Risk Management Advisory Committee convened a day-long meeting to discuss Nektar's application.

The proposed indication for the new agent was for the management of CLBP in adults who require daily around-the-clock long-term opioid treatment and have failed all other treatment options.

Although many committee members said the new agent has a lot of potential, they were unconvinced by the evidence presented that its benefits outweigh its risks.

"I heard a lot of ambiguity all day long, no matter what we talked about, and this is just too important an issue to approve a drug for chronic low back pain when there's just so much ambiguity about safety and efficacy," said committee chair Ronald Litman, MD, professor of anesthesia and pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia.

Less Abuse Potential?

Some committee members questioned the wisdom of adding yet another opioid to the market, especially without robust data to support it.

Meeting attendees heard that low back pain is one of the most common causes of chronic pain in the United States. About 25 million adults suffer from CLBP, defined as pain occurring on a frequent or daily basis over 3 months or more. The condition impairs the ability to perform basic activities of daily living and is the leading cause of disability.

Treatments include nondrug interventions such as ice, heat, acupuncture, exercise, and cognitive behavioral therapy. Opioids are an important component of pain management, but they often have side effects, including central nervous system-mediated adverse events such as sedation and cognitive impairment, and the potential for withdrawal symptoms.