In drug development, the tiniest of targets sometimes prove windows of huge opportunity. For chronic pain start-up Afferent Pharmaceuticals Inc., a single receptor subfamily may hold the key to unlocking novel treatments for that tough-to-alleviate disorder and a remarkable number of other diseases.

Adynxx Inc.’s first clinical candidate is a one-time treatment to keep acute postoperative pain out of the brain. The same pain pathway-blocking strategy underlies a therapeutic pipeline the company plans to develop for the huge need for a better solution for the five million patients in the US who are treated for chronic pain annually.

Katama Pharmaceuticals Inc. was built around tolperisone, a generic, oral small molecule muscle relaxant manufactured and sold in Europe for the treatment of muscular pain and neuromuscular spasms. Katama aims to launch its version in the US, initially for treating acute lower back pain.