How does Korsuva work?

Korsuva is a selective kappa opioid receptor (KOR) agonist used to help control intense itching (pruritus) in patients with chronic kidney disease undergoing hemodialysis.

Korsuva is thought to exert an anti-itching effect in hemodialysis patients by activation of kappa opioid receptors (KORs) on peripheral neurons and immune cells. Itching in patients undergoing hemodialysis is thought to be due to a build-up of toxins and an opioid system imbalance, including antagonism of peripheral KORs.

What is Korsuva used for?

In August 2021, the FDA approved Korsuva (difelikefalin) injection, a first-in-class kappa opioid receptor (KOR) agonist approved to treat moderate-to-severe pruritus (itching) associated with chronic kidney disease (CKD-aP) in adults undergoing hemodialysis. Korsuva is not classified as a controlled substance.

Chronic kidney disease (CKD) and end-stage renal disease (ESRD) are conditions in which your kidneys are not functioning normally and dialysis may be required. Itching can be experienced by up to 65% of patients undergoing dialysis in the US, and over 30% of patients may find the itching to be moderately-to-severely bothersome.

Repeated Itching can lead to skin damage, infections and long-term skin lesions.

How is Korsuva given?

Korsuva is given as an injection into your IV line at the end of each hemodialysis session. It is not recommended for use in patients undergoing peritoneal dialysis (fluid taken from abdomen).

How fast does Korsuva work for itching?

In studies, Korsuva led to reductions in itching by week 4 and this effect was sustained through week 12.

Studies

Korsuva was evaluated in the KALM 1 and KALM 2 Phase 3, placebo-controlled studies in over 850 adults undergoing hemodialysis who had moderate-to-severe pruritus (itching). In both studies, patients received either Korsuva 0.5 mcg/kg or placebo after hemodialysis three times weekly for 12 weeks.

Researchers assessed itching by using the Worst Itching Intensity Numerical Rating Scale (WI-NRS) scores, a validated scale (from 0-10) that can help patients communicate the intensity of their itch to healthcare professionals. It is a numerical rating ranging from 0 (“no itch”) to 10 (“worst itch imaginable”). Mean baseline WI-NRS scores were 7.1 and 7.2 in KALM-1 and KALM-2, respectively.

Results

Korsuva led to a 4 point or greater reduction in the Worst Itching Intensity Numerical Rating Scale (WI-NRS) scores in more patients receiving Korsuva compared to a placebo (an inactive agent) at week 12 (Study 1: 40% reduction [Korsuva] vs. 21% [placebo]; Study 2: 37% reduction [Korsuva] vs. 26% [placebo]). These results were statistically significant at week 12 in KALM 1.

In KALM 2,a significant itch reduction was seen by the 4th week of treatment (20% in Korsuva, 13% placebo) and sustained through week 12. By week 8, 31% of patients on Korsuva had a significant 4-point or greater reduction in WI-NRS vs. 21% placebo.

Common side effects with Korsuva

The most common side effects seen in clinical studies include:

• diarrhea
• dizziness
• nausea
• gait disturbances (including falls)
• hyperkalemia (high potassium blood levels)
• headache
• somnolence (sleepiness)
• mental status changes / confusion.

Somnolence (sleepiness) was more common in older adults (65 years of age and older) than in younger patients (7% vs. 3%).

This is not all the information you need to know about Korsuva (difelikefalin) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.