Cream Targeting Itch Shows Promise in Psoriasis
Jim Kling
DENVER — The topical TrkA kinase inhibitor CT327 reduces chronic itch in patients with psoriasis, according to results from a new study.
"This is an unmet need," said Gil Yosipovitch, MD, professor of dermatology at Temple University and the director of Temple Itch Center in Philadelphia.
"There are very few topical treatments that are targeted for chronic itch, and psoriasis has a significant component of itch that is not just related to the severity of the disease," he told Medscape Medical News.
Dr. Yosipovitch presented the research here at the American Academy of Dermatology 72nd Annual Meeting.
Unlike other topical medications that target inflammation, CT327 directly targets the itch. The drug is formulated with a technology called low systemic exposure, which prevents the inhibitor from getting past the upper layer of skin. This is important because TrkA inhibitors have been tested systemically in the past and can cause adverse effects, Dr. Yosipovitch explained.
His team conducted a phase 2b study of 160 patients with mild to moderate psoriasis who rated their itch on a visual analog scale.
Subjects had a Psoriasis Area and Severity Index score of around 9. Of the 95% of subjects who reported itch, the severity was at least moderate in 70% of patients and severe in 35%.
The subjects were divided into 4 groups of 40. The 3 treatment groups received CT327 ointment at concentrations of 0.05%, 0.1%, or 0.5%. The placebo group received the vehicle with no active ingredient.
There are so many types of skin diseases in which itch is predominant — that's what's exciting about it.
The overall reduction in itch was greater in the CT327 groups than in the placebo group (59.2% vs 21.2%; P < .05).
More patients in the CT327 groups than in the placebo group reported a reduction in itch of 50% (62% vs 32%). There was also a 10% to 15% overall reduction in the modified Psoriasis Area and Severity Index score in the CT327 groups (P < .05).
The topical cream was safe and well tolerated, and there was no evidence of application-site reactions.
These results could be good news for the 45% of psoriasis patients who find no itch relief from existing treatments. The next step is to conduct phase 3 trials, but the results are promising, said Dr. Yosipovitch.
Also encouraging is the fact that the itch continued to decrease throughout the 8-week course of treatment, and reappeared when the treatment was stopped. Blood work showed that the agent did not enter the bloodstream, and no photosensitivity or complaints indicative of systemic exposure were reported.
Itch is a common complaint, and Dr. Yosipovitch said he hopes that that CT327 will find applications in other skin conditions with chronic itch.
"We hope it will also work for atopic eczema, but we don't know yet. There are so many types of skin diseases in which itch is predominant — that's what's exciting about it," Dr. Yosipovitch added.
The cream will not replace steroidal creams because it does not address the inflammatory component of itch, he explained.
"It has some promise, without a doubt," said Jerry Krueger, MD, professor of dermatology at the University of Utah Health Sciences Center in Salt Lake City.
"You'd like to see some steeper improvement curves, but given that it's a new mechanism, these usually are pretty modest when they start. For a proof-of-concept type of study, I think it's very encouraging," Dr. Krueger told Medscape Medical News.
The study was funded by Creabilis. Dr. Yosipovitch is a consultant and is on the company's advisory board. Dr. Krueger has disclosed no relevant financial relationships.
American Academy of Dermatology (AAD) 72nd Annual Meeting. Presented March 22, 2014.