Hidradenitis Suppurativa (HS) (or acne inversa) (pdf) is a debilitating inflammatory skin disease characterized by recurrent abscesses and formation of sinus tracts, typically where the skin rubs together, e.g., armpits, groin, between the buttocks and under the breasts.
Reports of its prevalence range from roughly one-half of one percent up to approximately four percent of the general population. The etiology of the disease (pdf), which can cause significant physical and psycho-social distress, remains largely not understood. Though a bacterial component may (pdf) be at work (pdf) (e.g., see bacterial biofilm in acute lesions), as might a similar pathogenic mechanism to that of Crohn’s disease.
In 2015, Humira (adalimumab), "the Swiss Army knife of pharmaceutical drugs" (see below) was approved by the Food and Drug Administration (FDA) to treat moderate-to-severe cases of HS. The biologic, costing as high as $100,000 per year, is expected -- in 2017 -- to generate over $17 billion, worldwide, for AbbVie, $1bn of which attributable to HS sales. Other industry estimates on the size of the HS market estimate it closer to $750 million.
In a Phase 3 trial (n=307), as reported in The New England Journal of Medicine, 41.8 percent of the patients on Humira showed a reduction of at least 50 percent in the number of abscesses and inflammatory nodules. The reduction rate among patients on placebo was 26 percent. In a second Phase 3 trial (n=326), Humira elicited a 58.9 percent response versus 27.6 percent in the placebo group.
These results suggest there is a substantial opportunity for newer treatments in HS, as reflected in comments by Dr. Alexa Kimball, of Harvard Medical School in Boston, who participated in the Humira trials. "The magnitude of improvement with adalimumab treatment in our patients was relatively modest as compared with adalimumab treatment in patients with other diseases, and our patients were unlikely to have complete resolution of their symptoms."
Beyond its robust antimicrobial and wound-healing properties, highly relevant in HS, Brilacidin -- the Company’s immunomodulatory drug candidate in mid-stage testing -- also exhibits anti-inflammatory effects on key effector cells that may be involved in HS.
The condition, along with eczema and acne, represent potential potential future applications of Brilacidin in the area of dermatology.