Efficacy and Safety of Tocilizumab for Acute Chest Syndrome Treatment in Patients With Sickle Cell Disease

Inclusion criteria

• SCD patient of all genotypes (SS, SC, S/β0 and S/β+ or other major SCD syndrome)
• Age ≥ 2 years old
• Hospitalized for ACS, defined by the WHO as the association of fever and/or acute respiratory symptoms with a new pulmonary infiltrate on chest imaging, (X-ray, lung ultrasound, or CT scan)
• Requiring supplemental oxygen ≥ 2 L/min for SpO2 ≥ 95% or non-invasive respiratory support (high flow nasal oxygen or continuous positive airway pressure or bilevel non-invasive ventilation) or invasive mechanical ventilation or ECMO, for less than 48 hours
• Negative pregnancy test for girls or women of childbearing age
• Freely given, informed and written consent of patient or legal representatives
• Affiliation to the social security (or health insurance)
• Effective contraception up to 3 months after the administration of treatment (tocilizumab or placebo)

Exclusion criteria

• Impossibility to perform tocilizumab/placebo injection within the first 48 hours of supplemental oxygen ≥2L/min for SpO2≥95% and/or respiratory support (as defined in inclusion criteria n°4). If exchange transfusion is indicated at inclusion, it has to be performed before the injection of tocilizumab/placebo.
• Known hypersensitivity to tocilizumab or its excipients
• Known active current severe bacterial, viral, fungal, mycobacterial, or other infections (including but not limited to tuberculosis and atypical mycobacterial disease, hepatitis B and C, and herpes zoster)
• Immunization with a live/attenuated vaccine within the last 4 weeks
• Immunomodulatory therapy, anti-rejection therapy, cell depleting therapies and investigational agents within the last 3 months
• History of severe allergic or anaphylactic reactions to human, humanized, or murine monoclonal antibodies
• History of diverticulitis, diverticulosis requiring antibiotic treatment, or chronic ulcerative lower gastrointestinal disease such as Crohn's disease, ulcerative colitis, or other symptomatic lower gastrointestinal conditions that might predispose a patient to perforations
• Evidence of malignant disease or malignancies diagnosed within the last 3 years
• Pregnancy or breastfeeding
• Imminent and inevitable progression towards death in the opinion of the investigator
• Absolute neutrophil count \< 1.0 G/L or platelets \< 50 G/L
• ALT or AST \> 5-fold the upper limit of normal
• Glomerular Filtration rate (GFR) \< 60 mL/min/1,73 m²
• Current enrolment in another interventional research concerning a medicinal product for human use