Study of Single Doses of SBT777101 in Subjects With Hidradenitis Suppurativa

Inclusion Criteria:

• Body mass index (BMI) ≤50 kg/m2, inclusive

• Diagnosis of clinically active moderate-to-severe HS (Hurley Stage 2 or 3)

• Total abscess or inflammatory nodule (AN) count of ≥5, affecting at least 2 distinctanatomic regions, with at least 1 accessible AN of adequate size for biopsy (diameter > 1 cm)

• Total draining tunnel (dT) count of ≤20

• Documented history of inadequate response or intolerance to at least a 3-monthcourse of 1 conventional systemic therapy (e.g., antibiotic) and 1 biologic drug (e.g., adalimumab or secukinumab)

• Doses of medications for HS must be stable for at least 5 weeks prior to study drugadministration

• Must agree to use highly effective method of contraception for at least 1 year postSBT777101 administration

Exclusion Criteria:

• Major surgery within 12 weeks prior to screening or planned within 12 months afterdosing

• History of or current inflammatory or other autoimmune disease

• Complex presentations of HS

• Skin disease other than HS that may confound clinical assessments or increasesubject risk in the study

• Uncontrolled concomitant cardiovascular, nervous system, pulmonary, renal, hepatic,endocrine, or gastrointestinal disease

• Active current infection or history of recurrent infections

• Active or untreated latent tuberculosis

• Primary or secondary immunodeficiency