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PARIS – while achieving across-the-board clinically meaningful improvements in quality of life measures in patients with hemodialysis-associated pruritus in a phase 2 study, Frédérique Menzaghi, PhD, reported at the annual congress of the European Academy of Dermatology and Venereology.
At present there is no approved medication in the United States or Europe for the often intense itching associated with chronic kidney disease. Off-label treatments have limited efficacy.
Dr. Menzaghi is senior vice president for research and development at Cara Therapeutics, which is developing difelikefalin.
More than half – 60% to 70% – of patients on hemodialysis for end-stage renal disease experience chronic pruritus, as do a smaller proportion of individuals with chronic kidney disease (CKD) not requiring dialysis. CKD-associated pruritus is a day-and-night itch that makes life miserable for affected patients. Not only must they endure the predictable complications of skin excoriation, including impetigo, ulcerations, papules, and prurigo nodularis, but they also experience sleep disruption, depressed mood, and a 10%-20% increased mortality risk compared with CKD patients without pruritus.
Difelikefalin is a potent and selective peripheral kappa opioid receptor agonist that doesn’t activate mu or delta opioid receptors. It’s a synthetic drug that mimics endogenous dynorphin. Its key attribute is that it doesn’t cross the blood/brain barrier, so it doesn’t pose a risk for adverse events caused by activation of central opioid receptors. Difelikefalin has two mechanisms of action in CKD-associated pruritus: an antipruritic effect due to inhibition of ion channels responsible for afferent peripheral nerve activity; and an anti-inflammatory effect mediated by activation of kappa opioid receptors expressed by immune system cells, according to Dr. Menzaghi.
She reported on 174 hemodialysis patients with moderate to severe CKD-associated pruritus who were randomized to a double-blind, phase 2, dose-ranging study featuring an intravenous bolus of difelikefalin at 0.5, 1.0, or 1.5 mcg/kg or placebo given immediately after each of the thrice-weekly hemodialysis sessions for 8 weeks.
An oral formulation of difelikefalin is also under investigation for treatment of CKD-associated pruritus. The IV version is being developed for hemodialysis patients because difelikefalin is renally excreted.
“We’re taking advantage of the fact that their kidneys aren’t working. The drug stays in the system until the next dialysis because it can’t be eliminated. It’s quite convenient for these patients,” she explained.
The primary endpoint in the phase 2 study was change from baseline through week 8 in the weekly average of a patient’s daily self-rated 0-10 worst itching intensity numeric rating scale (NRS) scores. All participants had to have a baseline NRS score of at least 4, considered the lower threshold for moderate itch. In fact, the mean baseline score was 6.7-7.1 in the four study arms.
The results
Sixty-four percent of patients on difelikefalin 0.5 mcg/kg – the most effective dose – experienced at least a 3-point reduction, compared with 29% of placebo-treated controls. And a 4-point or greater reduction in NRS from baseline was documented in 51% of patients on difelikefalin at 0.5 mcg/kg, compared with 24% of controls.
Although a 4-point difference is widely considered to represent clinically meaningful improvement in atopic dermatitis studies, Dr. Menzaghi said psychometric analyses of the difelikefalin trial data indicated that a 3-point or greater improvement in NRS score was associated with clinically meaningful change.
“Our data suggest that a 4-point change may not be generalizable to all conditions,” she said.
Hemodialysis patients with severe baseline itch typically improved to moderate itch on difelikefalin, while those with baseline moderate itch – that is, an NRS of 4-6 – dropped down to mild or no itch while on the drug.
“But that’s just a number. The question is, is that really clinically meaningful?” Dr. Menzaghi noted.
The answer, she continued, is yes. A high correlation was seen between reduction in itch intensity and improvement in quality of life. Scores on the 5-D Itch Scale and Skindex-10 improved two- to threefold more in the difelikefalin 0.5-mcg group than in controls. So did scores on the 12-item Medical Outcomes Study Sleep Scale assessing sleep restlessness, awakening during sleep, and trouble falling asleep.
“We think these results suggest that peripheral kappa opioid receptors play an integral role in the modulation of itch signals and represent a primary target for the development of antipruritic agents,” said Dr. Menzaghi.
Indeed, a phase 3 randomized trial of difelikefalin 0.5 mcg/kg versus placebo in 350 hemodialysis patients with CKD-associated itch is ongoing in the United States, Europe, Australia, and Korea. Also ongoing is a phase 2 U.S. study of oral difelikefalin in patients with CKD-associated pruritus, many of whom are not on hemodialysis. In January, the company announced that enrollment in a phase 3 U.S. study of difelikefalin injection (0.5 mcg/kg) in hemodialysis patients with moderate to severe CKD-associated pruritus had been completed. The trials are funded by Cara Therapeutics.
SOURCE: Menzaghi F. EADV Congress, Abstract FC0.4.7.
PARIS – while achieving across-the-board clinically meaningful improvements in quality of life measures in patients with hemodialysis-associated pruritus in a phase 2 study, Frédérique Menzaghi, PhD, reported at the annual congress of the European Academy of Dermatology and Venereology.
At present there is no approved medication in the United States or Europe for the often intense itching associated with chronic kidney disease. Off-label treatments have limited efficacy.
Dr. Menzaghi is senior vice president for research and development at Cara Therapeutics, which is developing difelikefalin.
More than half – 60% to 70% – of patients on hemodialysis for end-stage renal disease experience chronic pruritus, as do a smaller proportion of individuals with chronic kidney disease (CKD) not requiring dialysis. CKD-associated pruritus is a day-and-night itch that makes life miserable for affected patients. Not only must they endure the predictable complications of skin excoriation, including impetigo, ulcerations, papules, and prurigo nodularis, but they also experience sleep disruption, depressed mood, and a 10%-20% increased mortality risk compared with CKD patients without pruritus.
Difelikefalin is a potent and selective peripheral kappa opioid receptor agonist that doesn’t activate mu or delta opioid receptors. It’s a synthetic drug that mimics endogenous dynorphin. Its key attribute is that it doesn’t cross the blood/brain barrier, so it doesn’t pose a risk for adverse events caused by activation of central opioid receptors. Difelikefalin has two mechanisms of action in CKD-associated pruritus: an antipruritic effect due to inhibition of ion channels responsible for afferent peripheral nerve activity; and an anti-inflammatory effect mediated by activation of kappa opioid receptors expressed by immune system cells, according to Dr. Menzaghi.
She reported on 174 hemodialysis patients with moderate to severe CKD-associated pruritus who were randomized to a double-blind, phase 2, dose-ranging study featuring an intravenous bolus of difelikefalin at 0.5, 1.0, or 1.5 mcg/kg or placebo given immediately after each of the thrice-weekly hemodialysis sessions for 8 weeks.
An oral formulation of difelikefalin is also under investigation for treatment of CKD-associated pruritus. The IV version is being developed for hemodialysis patients because difelikefalin is renally excreted.
“We’re taking advantage of the fact that their kidneys aren’t working. The drug stays in the system until the next dialysis because it can’t be eliminated. It’s quite convenient for these patients,” she explained.
The primary endpoint in the phase 2 study was change from baseline through week 8 in the weekly average of a patient’s daily self-rated 0-10 worst itching intensity numeric rating scale (NRS) scores. All participants had to have a baseline NRS score of at least 4, considered the lower threshold for moderate itch. In fact, the mean baseline score was 6.7-7.1 in the four study arms.
The results
Sixty-four percent of patients on difelikefalin 0.5 mcg/kg – the most effective dose – experienced at least a 3-point reduction, compared with 29% of placebo-treated controls. And a 4-point or greater reduction in NRS from baseline was documented in 51% of patients on difelikefalin at 0.5 mcg/kg, compared with 24% of controls.
Although a 4-point difference is widely considered to represent clinically meaningful improvement in atopic dermatitis studies, Dr. Menzaghi said psychometric analyses of the difelikefalin trial data indicated that a 3-point or greater improvement in NRS score was associated with clinically meaningful change.
“Our data suggest that a 4-point change may not be generalizable to all conditions,” she said.
Hemodialysis patients with severe baseline itch typically improved to moderate itch on difelikefalin, while those with baseline moderate itch – that is, an NRS of 4-6 – dropped down to mild or no itch while on the drug.
“But that’s just a number. The question is, is that really clinically meaningful?” Dr. Menzaghi noted.
The answer, she continued, is yes. A high correlation was seen between reduction in itch intensity and improvement in quality of life. Scores on the 5-D Itch Scale and Skindex-10 improved two- to threefold more in the difelikefalin 0.5-mcg group than in controls. So did scores on the 12-item Medical Outcomes Study Sleep Scale assessing sleep restlessness, awakening during sleep, and trouble falling asleep.
“We think these results suggest that peripheral kappa opioid receptors play an integral role in the modulation of itch signals and represent a primary target for the development of antipruritic agents,” said Dr. Menzaghi.
Indeed, a phase 3 randomized trial of difelikefalin 0.5 mcg/kg versus placebo in 350 hemodialysis patients with CKD-associated itch is ongoing in the United States, Europe, Australia, and Korea. Also ongoing is a phase 2 U.S. study of oral difelikefalin in patients with CKD-associated pruritus, many of whom are not on hemodialysis. In January, the company announced that enrollment in a phase 3 U.S. study of difelikefalin injection (0.5 mcg/kg) in hemodialysis patients with moderate to severe CKD-associated pruritus had been completed. The trials are funded by Cara Therapeutics.
SOURCE: Menzaghi F. EADV Congress, Abstract FC0.4.7.
PARIS – while achieving across-the-board clinically meaningful improvements in quality of life measures in patients with hemodialysis-associated pruritus in a phase 2 study, Frédérique Menzaghi, PhD, reported at the annual congress of the European Academy of Dermatology and Venereology.
At present there is no approved medication in the United States or Europe for the often intense itching associated with chronic kidney disease. Off-label treatments have limited efficacy.
Dr. Menzaghi is senior vice president for research and development at Cara Therapeutics, which is developing difelikefalin.
More than half – 60% to 70% – of patients on hemodialysis for end-stage renal disease experience chronic pruritus, as do a smaller proportion of individuals with chronic kidney disease (CKD) not requiring dialysis. CKD-associated pruritus is a day-and-night itch that makes life miserable for affected patients. Not only must they endure the predictable complications of skin excoriation, including impetigo, ulcerations, papules, and prurigo nodularis, but they also experience sleep disruption, depressed mood, and a 10%-20% increased mortality risk compared with CKD patients without pruritus.
Difelikefalin is a potent and selective peripheral kappa opioid receptor agonist that doesn’t activate mu or delta opioid receptors. It’s a synthetic drug that mimics endogenous dynorphin. Its key attribute is that it doesn’t cross the blood/brain barrier, so it doesn’t pose a risk for adverse events caused by activation of central opioid receptors. Difelikefalin has two mechanisms of action in CKD-associated pruritus: an antipruritic effect due to inhibition of ion channels responsible for afferent peripheral nerve activity; and an anti-inflammatory effect mediated by activation of kappa opioid receptors expressed by immune system cells, according to Dr. Menzaghi.
She reported on 174 hemodialysis patients with moderate to severe CKD-associated pruritus who were randomized to a double-blind, phase 2, dose-ranging study featuring an intravenous bolus of difelikefalin at 0.5, 1.0, or 1.5 mcg/kg or placebo given immediately after each of the thrice-weekly hemodialysis sessions for 8 weeks.
An oral formulation of difelikefalin is also under investigation for treatment of CKD-associated pruritus. The IV version is being developed for hemodialysis patients because difelikefalin is renally excreted.
“We’re taking advantage of the fact that their kidneys aren’t working. The drug stays in the system until the next dialysis because it can’t be eliminated. It’s quite convenient for these patients,” she explained.
The primary endpoint in the phase 2 study was change from baseline through week 8 in the weekly average of a patient’s daily self-rated 0-10 worst itching intensity numeric rating scale (NRS) scores. All participants had to have a baseline NRS score of at least 4, considered the lower threshold for moderate itch. In fact, the mean baseline score was 6.7-7.1 in the four study arms.
The results
Sixty-four percent of patients on difelikefalin 0.5 mcg/kg – the most effective dose – experienced at least a 3-point reduction, compared with 29% of placebo-treated controls. And a 4-point or greater reduction in NRS from baseline was documented in 51% of patients on difelikefalin at 0.5 mcg/kg, compared with 24% of controls.
Although a 4-point difference is widely considered to represent clinically meaningful improvement in atopic dermatitis studies, Dr. Menzaghi said psychometric analyses of the difelikefalin trial data indicated that a 3-point or greater improvement in NRS score was associated with clinically meaningful change.
“Our data suggest that a 4-point change may not be generalizable to all conditions,” she said.
Hemodialysis patients with severe baseline itch typically improved to moderate itch on difelikefalin, while those with baseline moderate itch – that is, an NRS of 4-6 – dropped down to mild or no itch while on the drug.
“But that’s just a number. The question is, is that really clinically meaningful?” Dr. Menzaghi noted.
The answer, she continued, is yes. A high correlation was seen between reduction in itch intensity and improvement in quality of life. Scores on the 5-D Itch Scale and Skindex-10 improved two- to threefold more in the difelikefalin 0.5-mcg group than in controls. So did scores on the 12-item Medical Outcomes Study Sleep Scale assessing sleep restlessness, awakening during sleep, and trouble falling asleep.
“We think these results suggest that peripheral kappa opioid receptors play an integral role in the modulation of itch signals and represent a primary target for the development of antipruritic agents,” said Dr. Menzaghi.
Indeed, a phase 3 randomized trial of difelikefalin 0.5 mcg/kg versus placebo in 350 hemodialysis patients with CKD-associated itch is ongoing in the United States, Europe, Australia, and Korea. Also ongoing is a phase 2 U.S. study of oral difelikefalin in patients with CKD-associated pruritus, many of whom are not on hemodialysis. In January, the company announced that enrollment in a phase 3 U.S. study of difelikefalin injection (0.5 mcg/kg) in hemodialysis patients with moderate to severe CKD-associated pruritus had been completed. The trials are funded by Cara Therapeutics.
SOURCE: Menzaghi F. EADV Congress, Abstract FC0.4.7.
REPORTING FROM THE EADV CONGRESS
Key clinical point: Moderate to severe chronic itching associated with chronic kidney disease is a common and underrecognized problem with a huge quality of life impact.
Major finding: Sixty-four percent of hemodialysis patients on difelikefalin 0.5 mcg/kg experienced at least a 3-point reduction on a 0-10 worst daily itch numeric rating scale, compared with 29% of placebo-treated controls.
Study details: This phase 2, multicenter, 8-week, double-blind study comprised 174 patients with moderate to severe hemodialysis-related itching.
Disclosures: The study was sponsored by Cara Therapeutics and presented by a company officer.
Source: Menzaghi F. EADV Congress, Abstract FC0.4.7.