Difelikefalin is a peripherally acting kappa opioid receptor (KOR) agonist, that is being developed as a potential first-in-class pruritus treatment.
The eight-week, double-blind, multicentre, randomised, placebo-controlled Phase II clinical trial assessed the oral difelikefalin’s safety and efficacy to treat moderate-to-severe pruritus in about 120 NP patients.
In the trial, the participants were randomised to take 2mg oral difelikefalin twice a day versus placebo for eight weeks and later the study was extended to four more weeks.
The findings showed that the oral difelikefalin group achieved the primary endpoint of change in the Worst Itch-Numeric Rating Scale (WI-NRS) score from baseline at week-8.
A significant improvement was also observed in the group at week-1 and is sustained through week-8.
Additionally, a statistically significantly higher part of oral difelikefalin group patients achieved a ≥4-point improvement in WI-NRS score compared to placebo group at week-8.
The company noted that the oral difelikefalin was well tolerated with a consistent safety profile observed in the earlier clinical trials.
Cara Therapeutics chief medical officer Joana Goncalves said: “We are pleased to have demonstrated clinical proof of concept for oral difelikefalin in the treatment of pruritus associated with notalgia paresthetica.
“These topline results coupled with the results from our other programs support the broad development of oral difelikefalin across disease areas regardless of the underlying cause of pruritus.
“We look forward to completing our data analyses and discussing next steps with the U.S. Food and Drug Administration.”
The most common adverse events observed in the study include dizziness, increase in urine output, nausea, constipation, and headache.