Treatment of Acute Ischemic Stroke (ReMEDy2 Trial)

This is a Phase 2/3 study evaluating the safety and efficacy of DM199 (rinvecalinase alfa) in treating participants with moderate stroke severity, who present within 24 hours of Acute Ischemic Stroke (AIS) onset due to small and medium vessel occlusions. This study focuses on participants with limited treatment options. Participants who have or will receive mechanical thrombectomy (MT) are not eligible for participation. Additionally, participants who have received fibrinolytics are excluded unless they experience a persistent neurological deficit of moderate severity six or more hours after fibrinolytic treatment. Participants considered for this trial should not be denied the use of standard of care (SoC) AIS therapies, such as fibrinolytics or MT, when appropriate. The double-blinded study will be randomized and placebo-controlled at up to approximately 100 sites.

Inclusion Criteria: 1. Participant is between 18 and 90 years of age inclusive. 2. Participant weight is 40 kg to 166 kg inclusive. 3. Participant to be randomized and treatment initiated within 24 hours of last known normal/AIS stroke onset. 4. Participant has NIHSS ≥5 and ≤15 at approximately the time of randomization. This criterion also applies to participants who meet the following conditions: * The participant initially presents with an NIHSS score below 5 but clinically worsens, including cases of progressing stroke / stroke-in-evolution, resulting in a subsequent persistent NIHSS score of ≥5 and ≤15; and * Participant meets all other inclusion and exclusion criteria, including repeat brain imaging to rule out hemorrhagic transformation. 5. Participant had a pre-morbid mRS score of 0 to 1 (mRS score prior to AIS) as stated by participant or participant's representative. 6. If participant has received fibrinolytic treatment for AIS within 4.5 hours of last know normal/AIS stoke onset and at least 6 hours after completing fibrinolytic treatment, and the participant meets all of the following criteria: * Participant's initial NIHSS score prior to fibrinolytics was ≤15; and * At least six hours after fibrinolytics, the participant has NIHSS score of ≥5 and ≤15 with a persistent deficit; and * The participant's NIHSS score showed less than a 4-point improvement, or worsened, after receiving fibrinolytics; and * Participant meets all other inclusion and exclusion criteria including repeat brain imaging to rule out hemorrhagic transformation. 7. Participant and/or legally authorized representative is able to provide informed consent. 8. Participant is willing and able to comply with the study protocol, in the Investigator's judgment. Exclusion Criteria: 1. At screening, or with repeat imaging (see Inclusion 4 and 6), participant has imaging confirmed hemorrhage stroke. 2. Participant has image findings with symptomatic large vessel occlusion at one or more of the following locations: Intracranial carotid I/T/L or M1 segment MCA, vertebral or basilar artery (BA). 3. Participant has large core of established infarction defined as ASPECTS 0-5. 4. Participant has or will receive MT for their current AIS. 5. Participant has suspected or confirmed extracranial arterial dissection. 6. Participant has imaging findings and/or symptoms consistent with a brain stem or cerebellar stroke. Posterior cerebral artery strokes without any associated brain stem or cerebellar involvement are allowable. 7. Participant has any recorded SBP \