ACADIA Pharmaceuticals has reported top-line data from a Phase II clinical trial of its investigational drug, ACP-044, to treat acute pain after orthopaedic surgery (bunionectomy).

A non-opioid, redox modulator, ACP-044 is being developed to treat acute and chronic pain.

The multicentre, parallel-group, randomised, double-blind, placebo-controlled trial analysed the efficacy and safety of ACP-044 to treat acute postoperative pain following bunionectomy.

It enrolled a total of 239 subjects who have undergone bunion removal on one foot. 

Participants were categorised to receive either a once-a-day dose of 1,600mg ACP-044, 400mg every six hours or a placebo, with the first dose given before surgery and the treatment continuing for four days. 

Using the Numeric Rating Scale (NRS), which scores pain on a 0-10 scale, trial subjects self-reported the intensity of pain.

Findings showed that the trial failed to meet the primary endpoint, a comparison of cumulative pain intensity scores over 24 hours in the treatment groups.

A trend favouring treatment with 400mg ACP-044 given once every six hours was reported on the primary endpoint, a difference of -10.5 points versus placebo.

Furthermore, at 48 and 72 hours, these numerical trends were observed to be reliably better than placebo but were not statistically significant.

Mild-to-moderate adverse events were reported without any serious adverse events linked to ACP-044 observed. 

Acadia Pharmaceuticals CEO Steve Davis said: “We are disappointed that the ACP-044 bunionectomy study did not meet its primary endpoint, especially given the significant need for novel, non-opioid treatment options for postsurgical pain. 

“We will continue to analyse the totality of the data to best determine whether further development in acute pain is appropriate.”

The company is currently assessing ACP-044 in a trial underway to treat osteoarthritis, which is anticipated to conclude in the first half of next year.

Last December, Acadia reported positive data from the Phase III Lavender trial of trofinetide for the treatment of Rett syndrome.