Rapid Reduction and Strict Complete Response in Itch With Oral Difelikefalin in Subjects With Notalgia Paresthetica and Moderate-to-Severe Pruritus

In a phase 2, multicenter, randomized, double-blind study involving 126 subjects with notalgia paresthetica and moderate-to-severe pruritus, oral difelikefalin (DFK) demonstrated significant efficacy in reducing itch intensity. Subjects were treated with either DFK 2 mg or placebo twice daily for 8 weeks. The study found that 14% of subjects treated with DFK achieved a strict complete response in itch by week 3, compared to 1% in the placebo group, with results maintained through week 8 (25% vs 4%). These findings highlight the potential of kappa-opioid receptor activation in managing neuropathic itch.