Pain Drug Developer Adynxx Picks Up $16M for Another Clinical Trial

Xconomy San Francisco — 

Despite the wide range of pain relievers available, many patients find these drugs fall short of easing pain after surgery and during rehabilitation. Drug developer Adynxx is trying to address that pain with a new treatment developed to be administered to patients during surgery. The San Francisco-based biotech now has $16 million to continue testing its approach.

TPG Biotech, a new investor in the company, led the $16 million Series B round of funding. Domain Associates, which backed Adynxx’s $18 million Series A round in 2010, also participated in the latest financing.

Adynxx’s lead drug, AYX1, is administered as a spinal injection. When the company began clinical trials in 2012, Adynxx CEO Rick Orr told Xconomy that the company’s drug works by blocking a protein that acts like a master switch for multiple pain signaling pathways. Orr said that this approach could have the effect of preventing pain, rather than just treating it.

The idea of preventing post-surgical pain caught the eye of Cubist Pharmaceuticals, which paid $20 million in 2013 for the right to acquire Adynxx pending mid-stage clinical trial results. But after getting a look at those results in 2014, Cubist passed on its option to buy the company, saying that the “magnitude of the clinical response did not meet Cubist’s exercise criteria.” Cubist itself was acquired by Merck (NYSE: MRK) later that year.

To date, Adynxx has completed two Phase 2 proof-of-concept studies. Following the most recent study in 2015, which enrolled 120 patients who had knee replacement surgery, Adynxx said that a statistically significant number of patients treated with the drug reported less pain in a walking test compared against those given a placebo. Adynxx also said its drug met the secondary goal of reducing pain while these patients were at rest.

With no acquirer or partner standing by, Adynxx must go into Phase 3 clinical trials on its own. But first, the company is preparing yet another mid-stage study. The previous Phase 2 trials tested the Adynxx drug in different dosages. The company has now settled on a 660 milligram dose administered as a 6 milliliter injection, according to records filed on Adynxx plans to test that dose in 200 knee replacement patients randomized to receive the Adynxx drug or a placebo. The $16 milion Series B round will help fund that study.

Photo by Flickr user Joe Flintham via a Creative Commons license.