GPP is a life-threatening skin condition involving the widespread eruption of sterile pustules, with a clinical course that “can be relapsing with recurrent flares or persistent with intermittent flares,” Hervé Bachelez, MD, of the Université de Paris and coauthors wrote. GPP patients are often hospitalized, and mortality ranges from 2% to 16% from causes that include sepsis and cardiorespiratory failure.
“The role of the interleukin-36 pathway in GPP is supported by the finding of loss-of-function mutations in the interleukin-36 receptor antagonist gene (IL36RN) and associated genes (CARD14, AP1S3, SERPINA3, and MPO) and by the overexpression of interleukin-36 cytokines in GPP skin lesions,” therefore, IL-36 is a potential treatment target to manage flares, they explained.
In the multicenter, double-blind trial, published in the New England Journal of Medicine, the researchers randomized 35 adults with GPP flares to a single 900-mg intravenous dose of spesolimab and 18 to placebo. Patients in both groups could receive an open-label dose of spesolimab after day 8; all patients were followed for 12 weeks.
The primary study endpoint was the Generalized Pustular Psoriasis Physician Global Assessment (GPPGA) pustulation subscore of 0 at 1 week after treatment. The GPPGA ranges from 0 (no visible pustules) to 4 (severe pustules). At baseline, 46% spesolimab patients and 39% placebo patients had a GPPGA pustulation subscore of 3, and 37% and 33%, respectively, had a pustulation subscore of 4.
New option for flares in pustular psoriasis
After 1 week, 54% of the spesolimab patients had no visible pustules, compared with 6% of placebo patients; the difference was statistically significant (P < .001). The main secondary endpoint was a score of 0 or 1 (clear or almost clear skin) on the GPPGA total score after 1 week. Significantly more spesolimab patients had GPPGA total scores of 0 or 1, compared with placebo patients (43% vs. 11%, respectively; P = .02).
Overall, 6 of 35 spesolimab patients (17%) and 6% of those in the placebo groups developed infections during the first week, and 24 of 51 patients (47%) who had received spesolimab at any point during the study developed infections by week 12. Infections included urinary tract infections (three cases), influenza (three), otitis externa (two), folliculitis (two), upper respiratory tract infection (two), and pustule (two).
In the first week, 6% of spesolimab patients and none of the placebo patients reported serious adverse events; at week 12, 12% of patients who had received at least one spesolimab dose reported a serious adverse event. In addition, antidrug antibodies were identified in 23 (46%) of the 50 patients who received at least one dose of spesolimab.
“Symptoms that were observed in two patients who received spesolimab were reported as a drug reaction with eosinophilia and systemic symptoms (DRESS),” the authors noted. One patient had a RegiSCAR (European Registry of Severe Cutaneous Adverse Reactions) score and the other had a score of 3; a score below 2 indicates no DRESS, and a score of 2 or 3 indicates “possible DRESS,” they added.
“Because 15 of the 18 patients who were assigned to the placebo group received open-label spesolimab, the effect of spesolimab as compared with that of placebo could not be determined after week 1,” the researchers noted.
The study findings were limited by several factors including the short randomization period and small study population, the researchers noted. However, the effect sizes for both the primary and secondary endpoints were large, which strengthened the results.
The results support data from previous studies suggesting a role for IL-36 in the pathogenesis of GPP, and support the need for longer and larger studies of the safety and effectiveness of spesolimab for GPP patients, they concluded.
No FDA-approved therapy
“GPP is a very rare but devastating life-threatening disease that presents with the sudden onset of pustules throughout the skin,” Joel Gelfand, MD, professor of dermatology and director of the psoriasis and phototherapy center at the University of Pennsylvania, Philadelphia, said in an interview. “Without rapid treatment, GPP can result in death. Currently there are no [Food and Drug Administration]–approved treatments for this orphan disease.”
Dr. Gelfand said he was surprised by the degree of efficacy and the speed of the patient response to spesolimab, compared with placebo, which he described as “truly remarkable.” Based on the current study results, “spesolimab offers a tremendous step forward for our patients,” he added.
Looking ahead, Dr. Gelfand noted that “longer-term studies with a comparator, such as a biologic that targets IL-17, would be helpful to more fully understand the safety, efficacy, and role that spesolimab will have in real-world patients.”
On Dec. 15, Boehringer Ingelheim announced that the FDA had granted priority review for spesolimab for treating GPP flares.
The study was supported by Boehringer Ingelheim. Lead author Dr. Bachelez had no financial conflicts to disclose. Several authors are employees of Boehringer Ingelheim. Dr. Gelfand is a consultant for the study sponsor Boehringer Ingelheim and has received research grants from Boehringer Ingelheim to his institution to support an investigator-initiated study. He also disclosed serving as a consultant and receiving research grants from other manufacturers of psoriasis products.