WASHINGTON – The approval last year of the interleukin (IL)-36 receptor antagonist spesolimab for treating generalized pustular psoriasis flares brightened the treatment landscape for this rare condition, and a recently published phase 2 study suggests a potential role of spesolimab for flare prevention. But when it comes to pustular disease localized to the hands and feet – palmoplantar pustulosis – treatment options have only modest efficacy, and spesolimab appears not to work, according to speakers at the annual research symposium of the National Psoriasis Foundation.
"The IL-36 receptor antagonists don't seem to be quite the answer for [palmoplantar pustulosis] that they are for generalized pustular psoriasis [GPP]," Megan H. Noe, MD, MPH, assistant professor of dermatology at Harvard Medical School and a dermatologist at Brigham and Women's Hospital, Boston, said at the meeting.
Psoriasis affecting the hands and feet – both pustular and nonpustular – has a higher impact on quality of life and higher functional disability than does non-acral psoriasis, is less responsive to treatment, and has a "very confusing nomenclature" that complicates research and thus management, said Jason Ezra Hawkes, MD, a dermatologist in Rocklin, Calif., and former faculty member of several departments of dermatology. Both he and Dr. Noe spoke during a tough-to-treat session at the NPF meeting.
IL-17 and IL-23 blockade, as well as tumor necrosis factor (TNF) inhibition, are effective overall for palmoplantar psoriasis (nonpustular), but in general, responses are lower than for plaque psoriasis. Apremilast (Otezla), a phosphodiesterase-4 inhibitor, has some efficacy for pustular variants, but for hyperkeratotic variants it "does not perform as well as more selective inhibition of IL-17 and IL-23 blockade," he said.
In general, "what's happening in the acral sites is different from an immune perspective than what's happening in the non-acral sites," and more research utilizing a clearer, descriptive nomenclature is needed to tease out differing immunophenotypes, explained Dr. Hawkes, who has led multiple clinical trials of treatments for psoriasis and other inflammatory skin conditions.
Palmoplantar pustulosis, and a word on generalized disease
Dermatologists are using a variety of treatments for palmoplantar pustulosis, with no clear first-line choices, Dr. Noe said. In a case series of almost 200 patients with palmoplantar pustulosis across 20 dermatology practices, published in JAMA Dermatology, 35% of patients received a systemic therapy prescription at their initial encounter – most commonly acitretin, followed by methotrexate and phototherapy. "Biologics were used, but use was varied and not as often as with oral agents," said Dr. Noe, a coauthor of the study.
TNF blockers led to improvements ranging from 57% to 84%, depending on the agent, in a 2020 retrospective study of patients with palmoplantar pustulosis or acrodermatitis continua of Hallopeau, Dr. Noe noted. However, rates of complete clearance were only 20%-29%.
Apremilast showed modest efficacy after 5 months of treatment, with 62% of patients achieving at least a 50% improvement in the Palmoplantar Pustulosis Psoriasis Area and Severity Index (PPPASI) in a 2021 open-label, phase 2 study involving 21 patients. "This may represent a potential treatment option," Dr. Noe said. "It's something, but not what we're used to seeing in our plaque psoriasis patients."
A 2021 phase 2a, double-blind, randomized, placebo-controlled study of spesolimab in patients with palmoplantar pustulosis, meanwhile, failed to meet its primary endpoint, with only 32% of patients achieving a 50% improvement at 16 weeks, compared with 24% of patients in the placebo arm. And a recently published network meta-analysis found that none of the five drugs studied in seven randomized controlled trials – biologic or oral – was more effective than placebo for clearance or improvement of palmoplantar pustulosis.
The spesolimab (Spevigo) results have been disappointing considering the biologic's newfound efficacy and role as the first Food and Drug Administration–approved therapy for generalized pustular disease, according to Dr. Noe. The ability of a single 900-mg intravenous dose of the IL-36 receptor antagonist to completely clear pustules at 1 week in 54% of patients with generalized disease, compared with 6% of the placebo group, was "groundbreaking," she said, referring to results of the pivotal trial published in the New England Journal of Medicine.
And given that "preventing GPP flares is ultimately what we want," she said, more good news was reported this year in The Lancet: The finding from an international, randomized, placebo-controlled study that high-dose subcutaneous spesolimab significantly reduced the risk of a flare over 48 weeks. "There are lots of ongoing studies right now to understand the best way to dose spesolimab," she said.
Moreover, another IL-36 receptor antagonist, imsidolimab, is being investigated in a phase 3 trial for generalized pustular disease, she noted. A phase 2, open-label study of patients with GPP found that "more than half of patients were very much improved at 4 weeks, and some patients started showing improvement at day 3," Dr. Noe said.
An area of research she is interested in is the potential for Janus kinase (JAK) inhibitors as a treatment for palmoplantar pustulosis. For pustulosis on the hands and feet, recent case reports describing the efficacy of JAK inhibitors have caught her eye. "Right now, all we have is this case report data, mostly with tofacitinib, but I think it's exciting," she said, noting a recently published report in the British Journal of Dermatology.
Palmoplantar psoriasis
Pustular psoriatic disease can be localized to the hand and/or feet only, or can co-occur with generalized pustular disease, just as palmoplantar psoriasis can be localized to the hands and/or feet or, more commonly, can co-occur with widespread plaque psoriasis. Research has shown, Dr. Hawkes said, that with both types of acral disease, many patients have or have had plaque psoriasis outside of acral sites.
The nomenclature and acronyms for palmoplantar psoriatic disease have complicated patient education, communication, and research, Dr. Hawkes said. Does PPP refer to palmoplantar psoriasis, or palmoplantar pustulosis, for instance? What is the difference between palmoplantar pustulosis (coined PPP) and palmoplantar pustular psoriasis (referred to as PPPP)?
What if disease is only on the hands, only on the feet, or only on the backs of the hands? And at what point is disease not classified as palmoplantar psoriasis, but plaque psoriasis with involvement of the hands and feet? Inconsistencies and lack of clarification lead to "confusing" literature, he said.
Heterogeneity in populations across trials resulting from "inconsistent categorization and phenotype inclusion" may partly account for the recalcitrance to treatment reported in the literature, he said. Misdiagnosis as psoriasis in cases of localized disease (confusion with eczema, for instance), and the fact that hands and feet are subject to increased trauma and injury, compared with non-acral sites, are also at play.
Trials may also allow insufficient time for improvement, compared with non-acral sites. "What we've learned about the hands and feet is that it takes a much longer time for disease to improve," Dr. Hawkes said, so primary endpoints must take this into account.
There is unique immunologic signaling in palmoplantar disease that differs from the predominant signaling in traditional plaque psoriasis, he emphasized, and "mixed immunophenotypes" that need to be unraveled.
Dr. Hawkes disclosed ties with AbbVie, Arcutis, Bristol-Myers Squibb, Boehringer Ingelheim, Janssen, LEO, Lilly, Novartis, Pfizer, Regeneron, Sanofi, Sun Pharma, and UCB. Dr. Noe disclosed ties to Bristol-Myers Squibb and Boehringer Ingelheim.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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Cite this: The Challenges of Palmoplantar Pustulosis and Other Acral Psoriatic Disease - Medscape - Nov 13, 2023.
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