Boston-based Centrexion Therapeutics has finalized $67 million in Series D financing to fund upcoming phase 3 trials for its pain drug, CNTX-4975. Investors included New Enterprise Associates, which led the round, founding investor InterWest Partners, and several others – Quan Capital, ArrowMark Partners, certain investment funds advised by Clough Capital Partners L.P., 6 Dimensions Capital and Efung Capital.
While chronic pain is nothing new, the growing opioid epidemic and the desire for a nonopioid approach to managing it has added urgency to the problem.
Despite being just four years old, Centrexion is building a significant pipeline of non-opioid, non-steroidal pain medications. CNTX-4975 is being developed to treat pain from osteoarthritis and Morton’s Neuroma.
The drug is a synthetic trans-capsaicin, a chemical component in chili peppers with a long therapeutic history, and targets the TRPV1 receptor. Rather than blocking pain signals, the therapy deadens nerve fibers.
“We call it molecular neurosurgery,” said Kerrie Brady, chief business officer and EVP of corporate strategy, in a phone interview. “We’re using the drug for a true physical effect on the ends of pain-transmitting fibers. The synthetic capsaicin that’s in our injection interacts selectively with just the ends of the pains fibers and essentially gives them a haircut.”
This approach may produce long-lasting effects. In a phase 2 trial, the drug injected directly into arthritic knees reduced pain while walking for 24 weeks or longer. The majority of patients experienced 50 percent less pain – for some the reduction was as high as 90 percent. Side effects were similar to those in the control group.
A Deep-dive Into Specialty Pharma
A specialty drug is a class of prescription medications used to treat complex, chronic or rare medical conditions. Although this classification was originally intended to define the treatment of rare, also termed “orphan” diseases, affecting fewer than 200,000 people in the US, more recently, specialty drugs have emerged as the cornerstone of treatment for chronic and complex diseases such as cancer, autoimmune conditions, diabetes, hepatitis C, and HIV/AIDS.
“Traditionally, in pain drug development, a success is getting a 50 percent reduction in pain in 50 percent of your patients,” Brady said. “We got 67 percent. And systemic exposure is less than [what] you would get from a typical hot Thai chili meal.”
Though the company does not fully understand the mechanism, patients also experienced reduced swelling. Brady hypothesizes that increased activity might generate this added benefit.
With these strong results and the Series D, Centrexion is poised to move forward on two phase 3 studies. The first will give participants one injection and follow them for a year. The other trial will add a second dose. If the drug is ultimately approved, Brady foresees twice-a-year injections being the norm.
Centrexion may ultimately face stiff competition in the pain space. Cara Therapeutics, Hydra Biosciences, and others have pain drugs in the pipeline, though the indications don’t always overlap. Academic researchers at Duke and elsewhere are also working on the problem. But with five drugs in its pipeline, Centrexion has a deep bench. In addition, osteoarthritis affects more than 30 million people in the U.S. alone.
CNTX-4975 must still complete its phase 3 trials, putting approval at two to three years out. Still, if the phase 2 results can be replicated, it could have a promising future.
“The drug is out of the body in 24 hours, but the effect it has last for months,” said Brady. “The reduction from baseline pain is one of the largest that’s been published in a peer-reviewed paper.”
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