Table 1 Eligibility criteria for study patients

Aged 18 years or above.

Known or suspected infection at the time of consideration for the study.

Patients with confirmed aneurysmal SAH who have had an EVD inserted as part of their clinical care, that is expected to remain in situ for more than 48 hours.

Known allergy to Escherichia coli or any of the constituents of the study medication as established from the patient themselves, reliable representative, or clinical records.

IL-1Ra or placebo can be administered within 72 hours from ictus.

Previous or existing treatment with IL-1Ra.

Patients are likely to remain resident within the study centre for the next 7 days.

Previous or current treatment with medication suspected of interacting with IL-1Ra, such as TNF-α inhibitors.

Normal renal function (serum creatinine <177 μmol L^-1).

Known to have participated in a clinical trial of an investigational agent or device in the previous 30 days or for the period determined by the protocol of the study the patient has taken part in.

Willing and able to give informed consent or consent available from a patient’s personal representative (usually the next of kin) for study inclusion including agreement in principle to receive study intervention and undergo all study assessments.

Known pregnancy or breast-feeding.

Clinically significant concurrent medical condition which, at the CI’s (or designee’s) discretion, could affect the safety, tolerability, or efficacy in this study or would interfere with participation, administration of study treatment, or assessment of outcomes. For example, pre-existing malignancy.

Previous inclusion in the current study.

Inability or unwillingness of patient or patient’s personal representative to give written informed consent.