Vertex Pharmaceuticals said its experimental non-opioid drug met the main goal of a mid-stage study but showed little difference versus a placebo in reducing pain.

The study tested pain reduction in patients with a condition caused by a pinched nerve in the spine. It was not designed for comparison between the drug, suzetrigine, and placebo, Vertex said.

The condition, lumbosacral radiculopathy, has no specific approved treatments, and is commonly treated by nonsteroidal anti-inflammatory drugs, with surgery being the last resort.

The company said treatment with the drug showed a mean reduction of 2.02 points in a weekly average of daily leg pain intensity at 12 weeks, compared with the placebo group's similar pain reduction of 1.98 points.

Investors expected the drug to show a reduction of more than 2 points on the 11-point scale after adjusting for the placebo, at least three analysts said ahead of the data.

The drug works by blocking pain signals at their origin before they reach the brain. It previously succeeded in a late-stage study for acute pain and in a mid-stage trial in diabetic patients with chronic nerve pain.

The data on the treatment has come after decades of research into non-opioid drugs and multiple trial failures. Vertex theorizes that due to the way the drug works, it will not be as addictive as opioids.

Nearly 108,000 people died from drug overdose in the U.S. in 2022 and about 82,000 of those deaths involved opioids, according to government data.

The FDA is separately reviewing the drug's application for treating moderate-to-severe acute pain.