INTERACT4 Expansion - Validation Study (INTERACT4 Exp)

INTEnsive Ambulance-delivered Blood Pressure Reduction in Biomarker-identified Hyper-ACute Intracerebral Haemorrhage Trial - Validation Study

As an investigator-initiated and conducted, multi-centre, open-label, single-arm prospective observational trial, INTERACT4 Expansion aims to evaluate the diagnostic accuracy of GFAP measured using a point-of-care device, for identifying ICH in participants presenting with acute stroke-like symptoms in the pre-hospital setting compared with imaging-confirmed ICH.

Study Overview

• Status: Not yet recruiting
• Conditions: Intracerebral Hemorrhage
• Intervention / Treatment: Diagnostic test: LVOne

• Study Type: Observational
• Enrollment (Estimated): 465

Contacts and Locations

• Study Contact: Name: Craig Anderson, MD; Phone Number: +61 4039448107; Email: canderson@georgeinstitute.org.au
• Study Contact Backup: Name: Cheryl Carcel, MD; Email: ccarcel@georgeinsitute.org.au

Study Locations

• Australia
  • New South Wales
    • Sydney, New South Wales, Australia
      • Liverpool Hospital
      • Principal Investigator: Dennis Cordato
      • Contact: Cheryl Carcel; Phone Number: +61 2 8052 4508; Email: ccarcel@georgeinstitute.org.au
    • Sydney, New South Wales, Australia
      • Royal North Shore Hospital
      • Contact: Cheryl Carcel; Phone Number: +61 2 8052 4508; Email: ccarcel@georgeinstitute.org.au
      • Principal Investigator: Christopher Partyka
    • Sydney, New South Wales, Australia
      • Nepean Hospital
      • Contact: Cheryl Carcel; Phone Number: +61 2 8052 4508; Email: ccarcel@georgeinstitute.org.au
      • Principal Investigator: Sameen Haque
    • Sydney, New South Wales, Australia
      • New South Wales Ambulance
      • Contact: Cheryl Carcel; Phone Number: +61 2 8052 4508; Email: ccarcel@georgeinstitute.org.au
      • Principal Investigator: David Patterson

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients with suspected acute stroke presenting to ambulance services

Description

Inclusion Criteria:

1. Adults (age ≥18 years);
2. Acute syndrome that is due to presumed acute stroke, defined as FAST (Face, Arm, Speech, Time) scores of ≥2 with an arm motor deficit;
3. Time ≤3 hours from last seen well;
4. Systolic BP (SBP) ≥150mmHg.

Exclusion Criteria:

1. Participants in coma (no response to tactile/verbal stimulation); or/and do not respond to "P" or "U" on the alert/verbal/painful/unresponsive (APVU) responsiveness scale;
2. Severe known co-morbid disease (e.g. cancer, chronic airflow disease, severe dementia, severe heart failure, pre-existing disability [needing help]);
3. Known history of epilepsy or seizure at onset;
4. Recent head injury (where there is potential for another type of intracranial haemorrhage or head trauma);
5. Hypoglycaemia (glucose<4.0 mmol/L) as measured in the ambulance.

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Proportion of participants without ICH on hospital-based brain CT who are correctly identified as negative based on GFAP point-of-care measurement. (Specificity)	From enrolment to initial CT scan up until 7 day assessment

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of participants with ICH on hospital-based brain CT who are correctly identified as positive based on GFAP point-of-care measurement.		From enrolment to initial CT scan up until 7 day assessment
Proportion of participants with a positive GFAP point-of-care measurement who are confirmed to have ICH on hospital-based brain CT.		From enrolment to initial CT scan up until 7 day assessment
Proportion of participants with a negative GFAP point-of-care measurement who are confirmed to not have an ICH on hospital-based brain CT.		From enrolment to initial CT scan up until 7 day assessment
Feasibility of recruitment, assessed by the proportion of enrolled participants over the number of stroke calls in the participating networks during the study period.		From enrollment to end of the study.
Feasibility of protocol delivery, assessed by the proportion of participants for whom all required study assessments in the ambulance were completed among those in whom assessments were initiated.	Study assesments include: participant screening, GFAP testing with the point-of-care device, and data entry	From enrolment to transfer to hospital at day 1
Feasibility of GFAP testing in the prehospital setting, defined as the proportion of enrolled participants in whom GFAP testing was successfully completed using the point-of-care device in the ambulance.		From enrolment to transfer to hospital at day 1
Correlation of GFAP measurement by the point-of-care device against a laboratory assay.		From enrolment to transfer to hospital at day 1

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity, specificity, positive predictive value, and negative predictive value for identifying ICH using a (+) GFAP combined with a (-) D-dimer result on the point-of-care device, compared with hospital-based brain CT.	Exploratory outcome	From enrolment to initial CT scan up until 7 day assessment

Collaborators and Investigators

• Sponsor: The George Institute

Study record dates

Study Major Dates

• Study Start (Estimated): February 1, 2026
• Primary Completion (Estimated): November 1, 2026
• Study Completion (Estimated): June 1, 2027

Study Registration Dates

• First Submitted: September 17, 2025
• First Submitted That Met QC Criteria: November 13, 2025
• First Posted (Estimated): November 17, 2025

Study Record Updates

• Last Update Posted (Actual): November 19, 2025
• Last Update Submitted That Met QC Criteria: November 17, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Pathologic Processes; Hemorrhage; Intracranial Hemorrhages; Pathological Conditions, Signs and Symptoms; Cerebral Hemorrhage
• Other Study ID Numbers: P01720

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No