Americans filled roughly one opioid pain prescription for every two U.S. adults in 2020—despite a raging opioid epidemic, where 80,000 people a year fatally overdose. Everyone knows the drugs are dangerous, but patients need pain relief, and the alternatives are limited.

A nonaddictive pain pill that works as well as an opioid, with none of the same addiction risk and side effects, would be an instant blockbuster. Drug companies have met with repeated failures in their efforts to develop one, but Vertex Pharmaceuticals (ticker: VRTX) could be close to a breakthrough.

Late this year or early next, the company plans to announce the results of four studies of a pain drug it calls VX-548. Three of the studies are testing VX-548 taken over a short period as a treatment for acute pain, while a fourth aims to measure the efficacy of the drug when taken over a longer duration for chronic pain.

If the trials are successful, sales of VX-548 could hit $5.1 billion a year by 2030, according to Leerink Partners analyst David Risinger. That would be transformative for Vertex, which currently sells treatments for cystic fibrosis and records annual sales of under $10 billion.