A 16 week exploratory, Proof of Concept study to evaluate the effect of Fostamatinib (12 weeks of treatment) upon cutaneous inflammation in Hidradenitis Suppurativa.

Sample size: 20 patients Study duration: 16 weeks

Primary Endpoints:

Alterations in Gene Expression Profiling, cell counts (CD3+, CD11c+, Neutrophil Elastase+, CD20+, CD138+) at Week 4 compared to Baseline.

Alterations in Gene Expression Profiling, cell counts (CD3+, CD11c+, Neutrophil Elastase+, CD20+, CD138+) at Week 12 compared to Baseline.

Secondary Endpoints:

Safety and Tolerability (Grade 2/3 Adverse Effects); Changes in Disease Activity (Measures by AN count and IHS4 scoring).

Study procedures Clinical Examination, Patient Questionnaires, Skin Biopsy, Blood Draw, medical photography

Inclusion Criteria:

• Moderate to Severe (Hurley Stage 2 or 3) Hidradenitis Suppurativa as determined by the PI

Exclusion Criteria:

• Uncontrolled hypertension (systolic blood pressure [BP] ≥135 mmHg and/or diastolic BP ≥85 mmHg), unstable angina, congestive heart failure of New York Heart Association classification III or IV, serious cardiac arrhythmia requiring treatment (exceptions: atrial fibrillation, paroxysmal supraventricular tachycardia) at screening.
• History of myocardial infarction within 3 months prior to screening.
• Shock or hypotension requiring vasoactive peptides, such as dopamine, norepinephrine, epinephrine, or dobutamine at screening or at randomization.
• Renal function impairment with creatinine clearance <30 mL/min at screening (estimated glomerular filtration rate will be calculated using the modification of diet in renal disease equation).
• Liver function impairment with aspartate aminotransferase/alanine aminotransferase >=3x the upper limit of normal or bilirubin >2X the upper limit of normal at screening.
• Neutrophil count <1000/µL at screening.
• History of an allergic reaction or hypersensitivity to the study treatment or any component of the study treatment formulation.
• Has documented HIV infection or documented, active hepatitis B or hepatitis C infection.
• Women lactating, pregnant or of childbearing potential who are not willing to avoid becoming pregnant during the study.
• Individuals with concurrent use of systemic antibiotics/ oral retinoids/ systemic immunosuppressants (those with prior use of these medications must have conducted a washout period of 4 weeks or 5 half-lives of the drug, whichever is longer).
• Any medical, psychological or social condition that, in the opinion of the Investigator, would jeopardize the health or well-being of the participant during any study procedures or the integrity of the data.