Randomized, Placebo-Controlled Pilot Study of Intravenous ApTOLL in Acute Ischemic Stroke Patients Using RACE Scale for Prehospital Evaluation

The primary objective of this randomized pilot trial is to evaluate the **feasibility**, safety, and efficacy of administering ApTOLL 0.2 mg/kg intravenously at the pre-hospital level, specifically in an ambulance setting, for the treatment of **Acute Ischemic Stroke (AIS)**. This evaluation is crucial to guide future pivotal trials, potentially improving early intervention strategies for AIS, which is a leading cause of morbidity and mortality worldwide. The study aims to determine whether this approach can be effectively implemented in a pre-hospital environment, which could significantly impact patient outcomes by reducing time to treatment.

The clinical trial involves participants diagnosed with **Acute Ischemic Stroke (AIS)**, specifically targeting individuals with suspected acute large vessel occlusion stroke. The study population includes both male and female subjects, aged between 18 and 90 years, with non-significant pre-stroke functional disability, as indicated by a modified Rankin Scale score of 0 to 2. Participants are selected based on a RACE scale score greater than 4, identified in non-stroke ready centers or primary health centers, and must be located in the Barcelona and Girona areas. The trial does not include a vulnerable population. Women of childbearing potential are required to confirm a recent menstrual period and a negative pregnancy test, and must use highly effective birth control methods for a specified period post-dosing. The sponsor has not provided information regarding the total number of participants in the trial.

The clinical trial is designed as a **randomized**, double-blind, placebo-controlled pilot study to evaluate the feasibility, safety, and efficacy of ApTOLL for the treatment of **acute ischemic stroke** at the pre-hospital level. The trial involves the administration of ApTOLL at a dose of 0.2 mg/kg intravenously, with the aim of guiding future pivotal trials. The study is expected to run from May 31, 2023, to February 29, 2024, with a six-month enrollment window. Participants will be randomly assigned to receive either ApTOLL or a placebo, both administered via intravenous use.

The sequence of study visits begins with an inclusion (screening) visit, where potential participants are assessed based on specific inclusion criteria, such as a RACE scale score greater than 4, age between 18 and 90 years, and an estimated randomization time of less than 6 hours from symptom onset. Women of childbearing potential must confirm a negative pregnancy test and agree to use effective birth control methods. Follow-up visits will occur at specified intervals to monitor the participants' health status and collect data on primary and secondary endpoints, including the rate of very poor outcomes, mortality rate, and serious adverse events within 90 days post-randomization. The end-of-study visit will conclude the trial, assessing the final infarct volume and other relevant clinical outcomes.

Participant involvement is expected to last up to 90 days, with conditions for early termination including withdrawal of consent or significant adverse events. The primary endpoints focus on the enrollment process and pre-hospital workflow metrics, while secondary endpoints include clinical outcomes such as the modified Rankin Scale and NIHSS score. The trial aims to provide valuable insights into the potential of ApTOLL as a treatment for acute ischemic stroke, contributing to the development of future therapeutic strategies.

The clinical trial involves the administration of **ApTOLL**, an experimental medication formulated as a **concentrate for solution for injection/infusion**. The active substance in ApTOLL is **APTAMER-4FT**, a nucleic acid-based compound. The medication is administered intravenously at a dosage of 0.2 mg/kg. The maximum daily and total dose is 0.2 mg, with a treatment period limited to one day. ApTOLL is developed by APTATARGETS S.L. and is intended for use as a neuroprotector in the treatment of acute ischemic stroke. The administration is conducted at the pre-hospital level, specifically in an ambulance setting, to assess its feasibility, safety, and effectiveness.

The study also includes a **placebo** group, where participants receive ApTOLL-Placebo. The placebo is administered intravenously, mirroring the route of administration for ApTOLL, but contains no active substance. The placebo serves as a control to evaluate the effects of the experimental treatment. The maximum daily and total dose for the placebo is 0.0 mg, with a treatment period of one day. The use of a placebo is critical in maintaining the study's masked, placebo-controlled design, ensuring unbiased assessment of ApTOLL's therapeutic potential.

The efficacy of ApTOLL in the treatment of acute ischemic stroke will be assessed through a series of primary and secondary endpoints. Primary endpoints include the enrolment of the desired sample size within a six-month window, time to enrol the planned participants, the proportion of eligible patients enrolled, time metrics related to pre-hospital workflows, and the proportion of patients lost to follow-up or who withdraw consent. Secondary endpoints will evaluate the rate of very poor outcomes, defined as a modified Rankin Scale (mRS) score of 5 or 6 at 90 days, and the mortality rate at 90 days. Additionally, all serious adverse events (SAEs) occurring within the first 90 days post-randomization will be documented, with a focus on specific organ involvement.

Further secondary endpoints include early neurological worsening, assessed by an increase in the NIHSS score of 4 or more points persisting for over 24 hours, and final infarct volume at 72±24 hours on MRI-FLAIR. The NIHSS score at 72 hours will be assessed during hospitalization, and the modified Rankin Scale will be evaluated at 90 days post-randomization. Proinflammatory markers in blood will also be compared between study groups in patients with stroke. These efficacy parameters will be measured using validated scales and laboratory tests at specified timepoints, such as 72 hours and 90 days, to ensure comprehensive data collection and analysis.