UPDATED: Cara Therapeutics scores another positive PhII for lead opioid

Cara Therapeutics ($CARA) has cleared another mid-stage hurdle in its quest to land a slate of new drug approvals for its next-gen opioid therapy CR845.

Investigators for the Shelton, CT-based Cara will release topline data this morning demonstrating that the IV therapy hit the primary endpoint in a small study of uremic pruritus, a chronic itch that afflicts dialysis patients. And the biotech says the outcome should clear the way for their second late-stage study to get underway next year.

Cara's stock jumped 23% in premarket trading Thursday.

Cara pulled off a $55 million IPO last year largely on the promise of CR845, a "peripherally active" kappa opioid analgesic that bypasses the central nervous system, binding to nerve cells in a way that is designed to block pain at the source without the drug high--or other side effects like vomiting--that has spurred legions of abuse cases for mu opioid drugs such as morphine, fentanyl and hydromorphone. 

By steering around the CNS, they're looking to get their drug--there's an oral version in the pipeline--into a broader market. And the biotech hopes to qualify for the DEA's least restrictive classification for controlled substances--if not avoid it altogether.

"We think this is a gateway study," says CEO Derek Chalmers, demonstrating the kind of proof-of-concept data that opens doors to a variety of additional clinical programs and a wider market. 

In the latest test investigators say that CR845 spurred an average 48% drop in itch scores among 65 patients in the study when the drug arm was compared to a placebo, hitting the primary endpoint. There was also a significant drop in Skindex 10 scores, a secondary endpoint designed to assess their drug's impact on quality of life issues, while falling short of statistical significance on their itch-related sleep disturbance rating.

Chalmers noted that it's particularly noteworthy that they were able to nail down significant responses on the quality of life measures, not an easy task in the pain field. 

Cara already plans to mount its first Phase III for acute pain during this quarter, with the second to follow soon after.