Sweden-based Orexo has commenced patient dosing in a Phase III study to evaluate Zubsolv, a sublingual formulation of buprenorphine and naloxone.

The randomised, multicentre, blinded, parallel-group, active-controlled non-inferiority study is being conducted for a new clinical indication of Zubsolv, as treatment for people suffering from opioid dependence.

Around 300 patients will be enrolled in the trial to compare Zubsolv with buprenorphine.

The study started after a review by the US Food and Drug Administration (FDA), and is expected to complete in early 2014.

Orexo’s Zubsolv is expected to receive approval from the FDA by July for use in maintenance treatment of opioid dependence.

Orexo president and chief executive officer Nikolaj Sørensen said the company is working with the FDA to ensure the safe an on-time approval of Zubsolv for use in maintenance treatment.

"Around 300 patients will be enrolled in the trial to compare Zubsolv with buprenorphine."

"Once approved Zubsolv will be directed to the more than five million US citizens suffering from opioid dependence," Sørensen said.

"Our new clinical research programme will ensure that Zubsolv gains an important clinical practice differentiation and will ensure that patients can be offered Zubsolv from when they commence treatment for their opioid addiction."

In previous acceptance trials of Zubsolv, compared to the usual buprenorphine treatment for opioid addiction, 89% of trial participants favoured the drug candidate.

Currently all buprenorphine / naloxone combination products are licensed only for maintenance treatment in the US, whereas buprenorphine products without naloxone are being used for opioid dependence treatment.