ST udy of A lteplase for R espiratory Failure in S ARS-CoV-2 COVID-19 (STARS): A Vanguard Multicenter, Rapidly Adaptive, Pragmatic, Randomized, Controlled Trial

Background: Pulmonary vascular microthrombi have been proposed as a mechanism of COVID19 respiratory failure. We hypothesized that early administration of tissue-plasminogen activator(tPA) followed by therapeutic heparin would improve pulmonary function in these patients. Methods: Adults with COVID-19-induced respiratory failure were randomized May14, 2020-March 3, 2021 in two phases: Phase-1(n=36): control (standard-of-care) vs tPA-Bolus (50mg tPA IV-bolus followed by 7 days of heparin (goal aPTT=60-80s); Phase-2(n=14): control vs tPA-Drip (50 mg of tPA IV-bolus, followed by tPA drip 2mg/hr plus heparin 500U/hour over 24 hours, then heparin to maintain aPTT 60-80s/7 days). The primary outcome was PaO2/FiO2 improvement at 48 hours post-randomization. Secondary outcomes included: PaO2/FiO2 improvement>50% or PaO2/FiO2>=200 at 48hrs(COMPOSITE), ventilator-free days(VFD) and mortality. Findings: Fifty patients were randomized: Phase 1:17 control, 19 tPA-Bolus; Phase 2: 8 control, 6 tPA-Drip. There were no severe bleeding events in intervention groups. In tPA-Bolus patients, PaO2/FiO2 was significantly(p<0.017) higher than baseline at 6 through 168 hours post-randomization; controls experienced no significant improvements. Compared to controls, tPA-Bolus patients showed larger, but non-significant, improvements in PaO2/FiO2 at 48hours[16.9%(-8.3–36.8) vs 29.8%(4.5–88.7),p=0.11], resulting in more patients reaching the COMPOSITE outcome (11.8% vs 47.4%,p=0.03). Controls had less VFD[0.0(0.0–9.0) vs 12.0(0.0–19.0),p=0.11] and higher mortality(41.2% vs 21.1%,p=0.19) than tPA-Bolus patients, although not significantly. tPA-Drip patients did not experience benefit compared to simultaneously enrolled controls. Interpretation: The combination tPA-Bolus+heparin is safe in severe COVID-19 respiratory failure. A Phase 3 study is warranted given promising improvements in oxygenation, VFD, and mortality. Trial Registration: The trial was performed according to the Food and Drug Administration (FDA) Investigational New Drug regulations (IND 149634) and registered with ClinicalTrials.gov (NCT04357730). Funding: This investigator-initiated trial (NCT04357730) was funded by Genentech, Inc. Declaration of Interests: CDB, HBM, EEM, and MBY have patents pending related to both coagulation/fibrinolysis diagnostics and therapeutic fibrinolytics, and are passive co-founders and holds stock options in Thrombo Therapeutics, Inc. HBM and EEM have received grant support from Haemonetics and Instrumentation Laboratories. MBY has previously received a gift of Alteplase (tPA) from Genentech, and owns stock options as a co-founder of Merrimack Pharmaceuticals. CDB, HBM, EEM, JW, NH, DST, AS, and MBY have received research grant funding from Genentech. JW receives consulting fees from Camurus A. B.. All other authors have nothing to disclose. Ethics Approval Statement: All participating trial sites had study approval and oversight from their respective Institutional Review Boards. Due to the nature of the study, which enrolled critically ill patients on mechanical ventilation, informed consent for trial participation was obtained from each patient’s Legally Authorized Representative. An independent Data Safety Monitoring Board (DSMB) oversaw the safety of the trial with mandatory reviews at each interim analysis and for all suspected serious adverse events. Data were stored in a REDCap instrument sponsored by NIH/NCATS Colorado CTSA Grant Number UL1 TR002535.