Hidradenitis Suppurativa
Hidradenitis suppurativa severely affects the lives of millions of patients
Citryll is currently in Phase 2a trials for CIT-013 in hidradenitis suppurativa (HS).
HS is a chronic, debilitating, autoinflammatory skin disorder that affects approximately 2% of the US and European population. It is characterized by recurrent, painful skin lesions with nodules, abscesses, and pus-draining tunnels in areas where juxtaposed skin surfaces chafe or rub. HS lesions can progress into interconnected tunnels accompanied by scarring and irreversible tissue destruction.
The primary pathogenic event in HS is hair follicle obstruction leading to dilation and eventual rupture, to discharge the contents into the surrounding dermis. This initiates inflammatory cell infiltration into HS lesions.
Patients suffering from this disease have severely decreased quality of life with symptoms often leading to reduced mobility, social isolation, anxiety and depression. Current treatment options for HS are limited, with only IL-17 and TNFα targeting drugs approved, offering limited efficacy.
Neutrophils and ETs are key inflammatory drivers in hidradenitis suppurativa
Neutrophils are an important component of leukocyte infiltration into HS lesions. Analysis of skin biopsies has identified that those HS lesions are enriched with increasing ET levels associated with increased disease severity.
The pro-inflammatory and cytotoxic nature of ETs, and their abundance in HS positions CIT-013 as an exciting first-in-class therapeutic approach for this disease in which there remains significant unmet medical need.
Following the successful completion of safety studies with our lead antibody CIT-013, a Phase 2a study in HS started in November 2025.
ETs are widely distributed in HS skin biopsies
HS skin biopsy stained for citH3 (pink) and DNA (blue). The intracellular, punctate citH3 staining typical for maturing keratinocytes. ETs are identified as the diffuse extracellular citH3-positive signal, clearly present in the epidermis. Citryll unpublished data
Clinical trial opportunities for patients
Citryll is conducting clinical trials for CIT-013, an investigational therapy developed to address Rheumatoid Arthritis (RA) and Hidradenitis Suppurativa (HS). This clinical research seeks to understand CIT-013’s potential effectiveness, safety, and impact on patient quality of life. We expect two clinical trials to start by mid 2025.