Anti-Interleukin-6 (IL6) in Calciphylaxis

Inclusion criteria

• Must have a clinical diagnosis of calciphylaxis (calcific uremic arteriolopathy) as determined by a board-certified dermatologist or surgeon.
• Diagnosis must be supported by either:

• Histopathology: A skin biopsy showing characteristic medial arteriolar calcification, subintimal fibrosis, or microvascular thrombosis.
• Clinical Presentation: In cases where a biopsy is clinically contraindicated, the presence of characteristic ischemic or necrotic skin lesions in a distribution typical for calciphylaxis (e.g., adipose-rich areas like the abdomen, thighs, or buttocks).
• Must have advanced kidney disease, defined as:

• End-Stage Kidney Disease (ESKD): Requiring maintenance hemodialysis or peritoneal dialysis.
• Chronic Kidney Disease (CKD): Stage 4 or 5 [estimated Glomerular Filtration Rate (eGFR) < 30 mL/min/1.73m²].
• Participants must be able to understand and provide written informed consent. in accordance with local institutional and regulatory guidelines.
• Subjects of childbearing potential must agree to use highly effective contraception for the duration of the study and for at least 3 months following the final dose of Tocilizumab.
• Must be willing to undergo blood draws for systemic biomarker analysis (CRP, sTF) as outlined in the study schedule, and safety monitoring.

Exclusion criteria

• Presence of any active, clinically significant infection (bacterial, viral, fungal, or opportunistic) that, in the opinion of the investigator, would pose an unacceptable risk to the patient during IL-6 inhibition.
• Known history of diverticulitis, intestinal perforation, or active gastrointestinal ulceration, due to the increased risk of GI perforation associated with tocilizumab.
• Evidence of active tuberculosis (TB) or untreated latent TB [confirmed via positive Interferon-Gamma Release Assay (IGRA) or purified protein derivative (PPD) skin test].
• Evidence of active Hepatitis B [HBsAg positive, or HBcAb positive with detectable hepatitis B virus (HBV) DNA) or active Hepatitis C (HCV RNA positive]
• Absolute Neutrophil Count (ANC) < 1,500 cells/mm³.

• Platelet count < 100,000 cells/mm³.
• Hemoglobin < 8.0 g/dL.
• Baseline elevations of (alanine aminotransferase test (ALT) or aspartate aminotransferase test (AST) > 1.5 times the upper limit of normal (ULN).
• Known active malignancy or a history of malignancy within the last 5 years (excluding successfully treated non-melanoma skin cancer or carcinoma in situ of the cervix).
• History of multiple sclerosis or other central demyelinating disorders.
• Recent or planned use of other biological response modifiers (e.g., tumor necrosis factor (TNF)-alpha inhibitors, IL-1 receptor antagonists, or B-cell depleting agents) within 3 months prior to enrollment.
• Receipt of a live or attenuated vaccine within 4 weeks prior to the first dose, or planned vaccination during the study period and for 4 weeks following the final dose.
• Known hypersensitivity to tocilizumab or any of its excipients.
• Pregnant or breastfeeding women, or those planning to become pregnant during the study period.
• Individuals who are unable to provide personal informed consent and do not have a Legally Authorized Representative (LAR) available to provide consent on their behalf
• Any other concurrent medical or psychiatric condition that, in the investigator's judgment, would make the subject inappropriate for the study or interfere with safety evaluations.
• Prisoners