Affibody AB has reported positive 16-week data from its global Phase III trial of izokibep in hidradenitis suppurativa (HS), a chronic skin condition marked by painful nodules, abscesses, and draining fistulas.
The French company unveiled during a late-breaking session at the European Academy of Dermatology & Venereology (EADV) Congress, which took place in Paris from 17-20 September. In addition to HS, Affibody is also exploring izokibeb’s use as a treatment for psoriatic arthritis (PsA).
Phase III data
The randomized, double-blind, placebo-controlled study (NCT05905783) evaluated 258 patients with moderate-to-severe HS, testing weekly 160 mg doses of izokibep against placebo. By week 12, the trial had already met its primary endpoint of HiSCR75—a 75% reduction in abscesses and inflammatory nodules with no worsening of abscesses or draining fistulas. Results presented at week 16 showed a deepening of responses across multiple measures.
Notably, 37% of patients receiving izokibep achieved HiSCR75 compared with 20% on placebo (p<0.01). Higher-order responses also demonstrated clear benefit: 24% of izokibep patients reached HiSCR90 versus 12% for placebo (p<0.05), while 21% achieved complete clearance (HiSCR100) compared with 9% in the control group (p<0.01).
“Hidradenitis suppurativa is a painful, chronic disease that profoundly affects patients’ well-being, underscoring the urgent need for better treatments,” said principal investigator Dr. Kim Papp of the University of Toronto. “The significant responses we observed with izokibep, particularly in complete disease resolution, are very encouraging and could mean a real difference for patients.”
Beyond lesion clearance, patients reported improvements in pain and quality of life. Among those with a baseline pain score of 4 or higher, 38% of izokibep-treated patients achieved at least a three-point reduction, compared with 17% on placebo (p<0.01). Dermatology Life Quality Index scores also improved significantly, with izokibep patients showing a mean reduction of –4.4 versus –2.9 for placebo (p<0.05).
Safety results were favorable. Izokibep was well-tolerated, with no reports of Candida infection, inflammatory bowel disease, or suicidal ideation—concerns that have been associated with broader IL-17 inhibitors.
Affibody CEO David Bejker welcomed the findings, stating: “We are very pleased with the 16-week data, which demonstrate both depth of response and improvements in hard-to-reach endpoints. With its strong Phase III profile and clear regulatory path, izokibep has the potential to be a game-changer for patients.”
Path Forward
Izokibep, an Affibody molecule, is a small therapeutic protein designed to inhibit IL-17A with high potency and enhanced tissue penetration. According to the company, the therapy’s unique structure, about one-tenth the size of monoclonal antibodies, confers pharmacokinetic advantages that may translate into differentiated clinical benefits.
The drug is also in late-stage development for PsA, where it has shown efficacy on par with established IL-17 inhibitors, and exploratory studies in ankylosing spondylitis. Affibody hopes the latest HS results will bolster regulatory submissions and partnerships in these indications.
