New Topicals for Excessive Sweating Are in Sight

Bruce Jancin

August 06, 2020

Safe and effective new prescription topical therapies for primary axillary hyperhidrosis took a giant step closer to reaching clinical practice following positive reports from two phase 3, randomized, controlled trials of novel agents presented at the virtual annual meeting of the American Academy of Dermatology.

Both investigational topical anticholinergic agents — 5% sofpironium bromide (SPB) gel and 1% glycopyrronium bromide (GPB) cream — met all of the efficacy and safety endpoints required by the Food and Drug Administration.

Primary axillary hyperhidrosis, or symmetrical bilateral excessive armpit sweating, has a prevalence worldwide of 1%-16%, with 5%-6% the most frequently cited numbers. The condition has a strong adverse impact on quality of life. Primary axillary hyperhidrosis is not caused by a disorder of the sweat glands; rather, it's actually a dysregulation of the autonomic nervous system leading to disproportionate sweating, explained Christoph Abels, MD, PhD, medical director at Dr. August Wolff in Bielefeld, Germany.

"What's surprising is that more than 50% of patients do not receive appropriate treatment, very likely due to lack of awareness or embarrassment," he added.

Also, many patients are put off by the systemic side effects of the oral anticholinergic agents, which are the current off-label treatment mainstay for patients with moderate or severe disease, according to Tomoko Fujimoto, MD, PhD, director of Ikebukuro Nishiguchi Fukurou Dermatology, near Tokyo.

Sofpironium Bromide Gel

Dr. Fujimoto presented the results of a phase 3, double-blind, multicenter, 6-week, vehicle-controlled clinical trial conducted in 281 Japanese patients with moderate to severe primary axillary hyperhidrosis as defined by a baseline score of 3 or 4 on the 4-point Hyperhidrosis Disease Severity Scale (HDSS). Participants were randomized to self-application of 5% SPB gel or its vehicle once daily before bedtime.

Sofpironium bromide blocks the cholinergic response mediated by the M3 muscarinic receptor subtype expressed on eccrine sweat glands, thereby inhibiting sweating. The drug then undergoes breakdown into an inactive metabolite after reaching the blood.

An important aspect of both SPB gel and GPB cream is that these agents are rolled onto the axillae using a dedicated applicator. Patients never touch the medications with their hands, thus avoiding accidental exposure to the mucous membranes. This largely prevents problems with mydriasis and blurred vision as anticholinergic side effects, which has been an issue with glycopyrronium tosylate topical cloth wipes (Qbrexza), the first FDA-approved treatment for primary axillary hyperhidrosis.

The primary endpoint in the Japanese study was at least a 1-point improvement on the HDSS plus at least a 50% reduction in gravimetric sweat production between baseline and week 6. This composite outcome was achieved in 53.9% of patients in the active treatment arm, compared with 36.4% of controls.

The secondary endpoint consisting of a week-6 HDSS score of 1 or 2 – that is, underarm sweating that's either never noticeable or is tolerable – occurred in 60.3% of the sofpironium bromide group and 47.9% of controls, a between-group difference that achieved statistical significance by week 2, when the rates were 46.8% and 28.2%.

The reduction in total gravimetric weight of axillary sweat from a mean baseline of 227 mg collected over 5 minutes was also significantly greater in the SPB group: a decrease of 157.6 mg, compared with 127.6 mg in controls; a between-group difference that also was significant by week 2. The mean Dermatology Life Quality Index score dropped by 6.8 points in the active-treatment arm from a baseline of 11.3, a significant improvement over the mean 4.5-point drop in controls.

A new 5-point measure of subjective symptoms of primary axillary hyperhidrosis — the Hyperhidrosis Disease Severity Measure–Axilla (HDSM-Ax) — improved by 1.41 points in the SPB group, significantly better than the 0.93 points in vehicle-treated controls. About 48% of patients on SBP experienced at least a 1.5-point reduction on the HDSM-Ax, compared with 26% of controls.

Regarding safety, there was a 2% incidence of application-site itch or scale in the SBP group. Anticholinergic side effects consisted of a single case of mydriasis, another of constipation, and two complaints of thirst, all mild, none resulting in treatment discontinuation. There were no reports of headache or blurred vision.

"These results indicate that the safety risks of sofpironium bromide can be considered small and controllable," Dr. Fujimoto said. "Moreover, sofpironium bromide is a topical agent that patients can use by themselves, so it is highly convenient, unlike, say, botulinum toxin type A injections."

Glycopyrronium Bromide Cream

Following on the heels of a recently published dose-ranging study (Br J Dermatol. 2020 Jan;182[1]:229-231), Dr. Abels presented the 4-week outcomes of a phase 3a, double-blind, randomized, five-country trial of once-daily 1% GPB cream or placebo in 171 patients with moderate or severe primary axillary hyperhidrosis. A phase 3b, open-label, 72-week, long-term safety trial is ongoing in 516 patients.

The primary endpoint of the 4-week trial was the reduction in gravimetric sweat production from day 1 to day 29. A reduction of 50% or more was documented in 57.5% of the patients on GBP and 34.5% of controls. A 75% or greater reduction occurred in 32.2% of the active-treatment group and 16.7% of those on placebo. And a decrease of at least 90% was seen in 23% of patients on topical GBP, compared with 9.5% of controls. All these between-group differences were significant.

The FDA now requires a quality of life measurement as a coprimary endpoint in phase 3 hyperhidrosis studies, and the phase 3 GBP trial also served as the successful validation study for a new patient-reported quality of life instrument designed specifically for this purpose. The new tool, known as the Hyperhydrosis Quality of Life questionnaire (HidroQol), proved much more sensitive than the HDSS or DLQI for evaluating clinical improvement in response to treatment (Br J Dermatol. 2020 Jun 8. doi: 10.1111/bjd.19300).

Initial results from the long-term phase 3b safety study should be available this fall on the first 100 patients followed on topical GBP for 1 year and for 300 followed for 6 months, Dr. Abels said.

Dr. Fujimoto reported serving as a paid consultant to and speaker for Kaken Pharmaceutical, which is developing SBP gel with Brickell Biotech. Dr. Abels is an employee of the company that is developing GPB cream.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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