The Food and Drug Administration has approved Korsuva^TM, a difelikefalin injection, to treat moderate to severe pruritus linked with chronic kidney disease in adults undergoing hemodialysis.

It is a kappa-opioid receptor agonist that targets the peripheral nervous system. FDA approval depended on the phase 3 trial data KALM1 and KALM 2 trials and data from other 32 clinical studies. The KALM 1 trial results showed that 40% of difelikefalin-treated patients improved at least 4 points in the WI-NRS score at the 12th week compared with 21% for placebo. In the KALM 2 trial, 37% of the difelikefalin-treated patients attained a 4-point or better WI-NRS score versus 26% for placebo. Itch reduction was noticed at the end of week four and sustained through week 12. 

The most common adverse reactions reported with difelikefalin were diarrhea, dizziness, nausea, gait disturbances, including falls, hyperkalemia, headache, somnolence, and mental status change. 

It is available as a single dose vial containing 65 mcg/1.3 mL of difelikefalin as a sterile, preservative-free solution for intravenous injection. It will be available in the US markets in the first quarter of 2022. 

Reference:

1. Vifor Pharma and Cara Therapeutics announce US FDA approval of Korsuva™ injection for the treatment of moderate-to-severe pruritus in hemodialysis patients. News release. Vifor Pharma and Cara Therapeutics. Accessed August 24, 2021. https://www.businesswire.com/news/home/20210823005635/en/Vifor-Pharma-and-Cara-Therapeutics-announce-U.S.-FDA-approval-of-KORSUVA%E2%84%A2-injection-for-the-treatment-of-moderate-to-severe-pruritus-in-hemodialysis-patients.
2. Korsuva [package insert]. Stamford, CT: Cara Therapeutics, Inc.; 2021.