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High-titre methylene blue-treated convalescent plasma as an early treatment for outpatients with COVID-19: a randomised, placebo-controlled trial
Alemany A, Millat-Martinez P, Corbacho-Monné M, Malchair P, Ouchi D, Ruiz-Comellas A, Ramírez-Morros A, Rodríguez Codina J, Amado Simon R, Videla S, et al
The Lancet. Respiratory medicine. 2022
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Abstract
BACKGROUND Convalescent plasma has been proposed as an early treatment to interrupt the progression of early COVID-19 to severe disease, but there is little definitive evidence. We aimed to assess whether early treatment with convalescent plasma reduces the risk of hospitalisation and reduces SARS-CoV-2 viral load among outpatients with COVID-19. METHODS We did a multicentre, double-blind, randomised, placebo-controlled trial in four health-care centres in Catalonia, Spain. Adult outpatients aged 50 years or older with the onset of mild COVID-19 symptoms 7 days or less before randomisation were eligible for enrolment. Participants were randomly assigned (1:1) to receive one intravenous infusion of either 250-300 mL of ABO-compatible high anti-SARS-CoV-2 IgG titres (EUROIMMUN ratio ≥6) methylene blue-treated convalescent plasma (experimental group) or 250 mL of sterile 0·9% saline solution (control). Randomisation was done with the use of a central web-based system with concealment of the trial group assignment and no stratification. To preserve masking, we used opaque tubular bags that covered the investigational product and the infusion catheter. The coprimary endpoints were the incidence of hospitalisation within 28 days from baseline and the mean change in viral load (in log(10) copies per mL) in nasopharyngeal swabs from baseline to day 7. The trial was stopped early following a data safety monitoring board recommendation because more than 85% of the target population had received a COVID-19 vaccine. Primary efficacy analyses were done in the intention-to-treat population, safety was assessed in all patients who received the investigational product. This study is registered with ClinicalTrials.gov, NCT04621123. FINDINGS Between Nov 10, 2020, and July 28, 2021, we assessed 909 patients with confirmed COVID-19 for inclusion in the trial, 376 of whom were eligible and were randomly assigned to treatment (convalescent plasma n=188 [serum antibody-negative n=160]; placebo n=188 [serum antibody-negative n=166]). Median age was 56 years (IQR 52-62) and the mean symptom duration was 4·4 days (SD 1·4) before random assignment. In the intention-to-treat population, hospitalisation within 28 days from baseline occurred in 22 (12%) participants who received convalescent plasma versus 21 (11%) who received placebo (relative risk 1·05 [95% CI 0·78 to 1·41]). The mean change in viral load from baseline to day 7 was -2·41 log(10) copies per mL (SD 1·32) with convalescent plasma and -2·32 log(10) copies per mL (1·43) with placebo (crude difference -0·10 log(10) copies per mL [95% CI -0·35 to 0·15]). One participant with mild COVID-19 developed a thromboembolic event 7 days after convalescent plasma infusion, which was reported as a serious adverse event possibly related to COVID-19 or to the experimental intervention. INTERPRETATION Methylene blue-treated convalescent plasma did not prevent progression from mild to severe illness and did not reduce viral load in outpatients with COVID-19. Therefore, formal recommendations to support the use of convalescent plasma in outpatients with COVID-19 cannot be concluded. FUNDING Grifols, Crowdfunding campaign YoMeCorono.
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Casirivimab and imdevimab in patients admitted to hospital with COVID-19 (RECOVERY): a randomised, controlled, open-label, platform trial
Lancet (London, England). 2022;399(10325):665-676
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Abstract
BACKGROUND Casirivimab and imdevimab are non-competing monoclonal antibodies that bind to two different sites on the receptor binding domain of the SARS-CoV-2 spike glycoprotein, blocking viral entry into host cells. We aimed to evaluate the efficacy and safety of casirivimab and imdevimab administered in combination in patients admitted to hospital with COVID-19. METHODS RECOVERY is a randomised, controlled, open-label platform trial comparing several possible treatments with usual care in patients admitted to hospital with COVID-19. 127 UK hospitals took part in the evaluation of casirivimab and imdevimab. Eligible participants were any patients aged at least 12 years admitted to hospital with clinically suspected or laboratory-confirmed SARS-CoV-2 infection. Participants were randomly assigned (1:1) to either usual standard of care alone or usual care plus casirivimab 4 g and imdevimab 4 g administered together in a single intravenous infusion. Investigators and data assessors were masked to analyses of the outcome data during the trial. The primary outcome was 28-day all-cause mortality assessed by intention to treat, first only in patients without detectable antibodies to SARS-CoV-2 infection at randomisation (ie, those who were seronegative) and then in the overall population. Safety was assessed in all participants who received casirivimab and imdevimab. The trial is registered with ISRCTN (50189673) and ClinicalTrials.gov (NCT04381936). FINDINGS Between Sept 18, 2020, and May 22, 2021, 9785 patients enrolled in RECOVERY were eligible for casirivimab and imdevimab, of which 4839 were randomly assigned to casirivimab and imdevimab plus usual care and 4946 to usual care alone. 3153 (32%) of 9785 patients were seronegative, 5272 (54%) were seropositive, and 1360 (14%) had unknown baseline antibody status. 812 (8%) patients were known to have received at least one dose of a SARS-CoV-2 vaccine. In the primary efficacy population of seronegative patients, 396 (24%) of 1633 patients allocated to casirivimab and imdevimab versus 452 (30%) of 1520 patients allocated to usual care died within 28 days (rate ratio [RR] 0·79, 95% CI 0·69-0·91; p=0·0009). In an analysis of all randomly assigned patients (regardless of baseline antibody status), 943 (19%) of 4839 patients allocated to casirivimab and imdevimab versus 1029 (21%) of 4946 patients allocated to usual care died within 28 days (RR 0·94, 95% CI 0·86-1·02; p=0·14). The proportional effect of casirivimab and imdevimab on mortality differed significantly between seropositive and seronegative patients (p value for heterogeneity=0·002). There were no deaths attributed to the treatment, or meaningful between-group differences in the pre-specified safety outcomes of cause-specific mortality, cardiac arrhythmia, thrombosis, or major bleeding events. Serious adverse reactions reported in seven (<1%) participants were believed by the local investigator to be related to treatment with casirivimab and imdevimab. INTERPRETATION In patients admitted to hospital with COVID-19, the monoclonal antibody combination of casirivimab and imdevimab reduced 28-day mortality in patients who were seronegative (and therefore had not mounted their own humoral immune response) at baseline but not in those who were seropositive at baseline. FUNDING UK Research and Innovation (Medical Research Council) and National Institute of Health Research.
PICO Summary
Population
Patients from 12 years old admitted to hospital with COVID-19; enrolled in the RECOVERY trial which took part in 127 UK hospitals (n= 9,785).
Intervention
Casirivimab and imdevimab plus usual care (n= 4,839).
Comparison
Usual care alone (n= 4,946).
Outcome
In the primary efficacy population of seronegative patients, 396 (24%) of 1,633 patients allocated to casirivimab and imdevimab versus 452 (30%) of 1,520 patients allocated to usual care died within 28 days. In an analysis of all patients (regardless of baseline antibody status), 943 (19%) of 4,839 patients allocated to casirivimab and imdevimab versus 1,029 (21%) of 4,946 patients allocated to usual care died within 28 days. The proportional effect of casirivimab and imdevimab on mortality differed significantly between seropositive and seronegative patients. There were no deaths attributed to the treatment, or meaningful between-group differences in the pre-specified safety outcomes of cause-specific mortality, cardiac arrhythmia, thrombosis, or major bleeding events. Serious adverse reactions were reported in 7 (<1%) patients.
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Atorvastatin versus placebo in patients with covid-19 in intensive care: randomized controlled trial
BMJ (Clinical research ed.). 2022;376:e068407
Abstract
OBJECTIVE To assess the effect of statin treatment versus placebo on clinical outcomes in patients with covid-19 admitted to the intensive care unit (ICU). DESIGN INSPIRATION/INSPIRATION-S was a multicenter, randomized controlled trial with a 2×2 factorial design. Results for the anticoagulation randomization have been reported previously. Results for the double blind randomization to atorvastatin versus placebo are reported here. SETTING 11 hospitals in Iran. PARTICIPANTS Adults aged ≥18 years with covid-19 admitted to the ICU. INTERVENTION Atorvastatin 20 mg orally once daily versus placebo, to be continued for 30 days from randomization irrespective of hospital discharge status. MAIN OUTCOME MEASURES The primary efficacy outcome was a composite of venous or arterial thrombosis, treatment with extracorporeal membrane oxygenation, or all cause mortality within 30 days from randomization. Prespecified safety outcomes included increase in liver enzyme levels more than three times the upper limit of normal and clinically diagnosed myopathy. A clinical events committee blinded to treatment assignment adjudicated the efficacy and safety outcomes. RESULTS Of 605 patients randomized between 29 July 2020 and 4 April 2021 for statin randomization in the INSPIRATION-S trial, 343 were co-randomized to intermediate dose versus standard dose prophylactic anticoagulation with heparin based regimens, whereas 262 were randomized after completion of the anticoagulation study. 587 of the 605 participants were included in the primary analysis of INSPIRATION-S, reported here: 290 were assigned to atorvastatin and 297 to placebo (median age 57 years (interquartile range 45-68 years); 256 (44%) women). The primary outcome occurred in 95 (33%) patients assigned to atorvastatin and 108 (36%) assigned to placebo (odds ratio 0.84, 95% confidence interval 0.58 to 1.21). Death occurred in 90 (31%) patients in the atorvastatin group and 103 (35%) in the placebo group (odds ratio 0.84, 95% confidence interval 0.58 to 1.22). Rates for venous thromboembolism were 2% (n=6) in the atorvastatin group and 3% (n=9) in the placebo group (odds ratio 0.71, 95% confidence interval 0.24 to 2.06). Myopathy was not clinically diagnosed in either group. Liver enzyme levels were increased in five (2%) patients assigned to atorvastatin and six (2%) assigned to placebo (odds ratio 0.85, 95% confidence interval 0.25 to 2.81). CONCLUSIONS In adults with covid-19 admitted to the ICU, atorvastatin was not associated with a significant reduction in the composite of venous or arterial thrombosis, treatment with extracorporeal membrane oxygenation, or all cause mortality compared with placebo. Treatment was, however, found to be safe. As the overall event rates were lower than expected, a clinically important treatment effect cannot be excluded. TRIAL REGISTRATION ClinicalTrials.gov NCT04486508.
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Durable functional limitation in patients with coronavirus disease-2019 admitted to intensive care and the effect of intermediate-dose vs standard-dose anticoagulation on functional outcomes
European journal of internal medicine. 2022
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Abstract
INTRODUCTION Patients affected with severe forms of coronavirus disease 2019 (COVID-19) suffer from a wide range of sequelae, from limited airway diseases to multiple organ failure. These sequelae may create exercise limitation, impair the daily activity and thus impact the mental health and the social life. However, the extent of functional limitations and depressive symptoms are understudied especially in patients with COVID-19 after intensive care unit (ICU) hospitalization. METHODS The Intermediate versus Standard-dose Prophylactic anticoagulation In cRitically-ill pATIents with COVID-19: An opeN label randomized controlled trial (INSPIRATION) was a clinical trial that randomized ICU patients with COVID-19 to intermediate-dose vs standard-dose anticoagulation. In the current study, we assessed the interval change in 30-day and 90-day functional limitations based on the post-COVID-19 functional status scale (PCFS) and depressive symptoms based on the Patient Health Questionnaire-2 (PHQ-2) in the trial participants. We also assessed the effect of intermediate-dose vs standard-dose prophylactic anticoagulation on the functional outcomes and depressive symptoms. RESULTS Of 600 randomized patients in INSPIRATION, 375 (age: 62 years; 42% women) participated in the functional status study. 195 patients died during the 90-day follow up (191 by day 30). Among survivors, between day 30 and day 90, the proportion of patients with moderate-to-severe functional limitation (PCSF grade 3-or-4) decreased from 20.0% to 4.8% (P <0.001) and PHQ-2 ≥ 3 decreased from 25.5% to 16.6% (P = 0.05). The proportion of patients with no functional limitations (PCFS grade 0) increased (4.2% to 15.4%, P<0.001). Intermediate-dose compared with standard-dose prophylactic anticoagulation did not impact the 90-day proportion of patients with PCFS grade 3-or-4 (5.3% vs 4.2%; odds ratio (OR), 1.20, [95% CI, 0.46-3.11]; P = 0.80) or PHQ-2 ≥ 3 (17.9% vs 15.3%; OR, 1.14, [95% CI, 0.79-1.65]; P = 0.14), with similar results when accounting for study center. CONCLUSION In patients with COVID-19 admitted to the ICU, functional limitations and depressive symptoms were common at 30-day follow-up and had some improvement by 90-day follow-up among survivors. Intermediate-dose compared to standard-dose prophylactic anticoagulation did not improve functional outcomes.
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Neutralizing COVID-19 Convalescent Plasma in Adults Hospitalized with COVID-19: A Blinded Randomized Placebo-Controlled Trial
Self WH, Wheeler AP, Stewart TG, Schrager H, Mallada J, Thomas CB, Cataldo VD, O'Neal HR Jr, Shapiro NI, Higgins C, et al
Chest. 2022
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Abstract
BACKGROUND Convalescent plasma has been one of the most common treatments for COVID-19, but most clinical trial data to date have not supported its efficacy. RESEARCH QUESTION Is rigorously selected COVID-19 convalescent plasma with neutralizing anti-SARS-CoV-2 antibodies an efficacious treatment for adults hospitalized with COVID-19? STUDY DESIGN AND METHODS This was a multicenter, blinded, placebo-controlled randomized clinical trial among adults hospitalized with SARS-CoV-2 infection and acute respiratory symptoms for <14 days. Enrolled patients were randomly assigned to receive one unit of COVID-19 convalescent plasma (n=487) or placebo (n=473). The primary outcome was clinical status (illness severity) 14 days after study infusion measured with a seven-category ordinal scale ranging from discharged from the hospital with resumption of normal activities (lowest score) to death (highest score). The primary outcome was analyzed with a multivariable ordinal regression model, with an adjusted odds ratio (aOR) <1.0 indicating more favorable outcomes with convalescent plasma than placebo. In secondary analyses, trial participants were stratified by the presence of endogenous anti-SARS-CoV-2 antibodies ("serostatus") at randomization. The trial included 13 secondary efficacy outcomes, including 28-day mortality. RESULTS Among 974 randomized patients, 960 were included in the primary analysis. Clinical status on the ordinal outcome scale at 14 days did not differ between the convalescent plasma and placebo groups in the overall population (aOR: 1.04; 1/7 support interval (SI): 0.82-1.33), in patients without endogenous antibodies (aOR: 1.15; 1/7 SI: 0.74-1.80), or in patients with endogenous antibodies (aOR: 0.96; 1/7 SI: 0.72-1.30). None of the 13 secondary efficacy outcomes were different between groups. At 28 days, 89/482 (18.5%) patients in the convalescent plasma group and 80/465 (17.2%) patients in the placebo group had died (aOR: 1.04, 1/7 SI: 0.69-1.58). INTERPRETATION Among adults hospitalized with COVID-19, including those seronegative for anti-SARS-CoV-2 antibodies, treatment with convalescent plasma did not improve clinical outcomes.
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Single Dose of Ivermectin is not Useful in Patients with Hematological Disorders and COVID-19 Illness: A Phase II B Open Labelled Randomized Controlled Trial
George B, Moorthy M, Kulkarni U, Selvarajan S, Rupali P, Christopher DJ, Balamugesh T, Rose W, Lakshmi,KM, Devasia AJ, et al
Indian journal of hematology & blood transfusion : an official journal of Indian Society of Hematology and Blood Transfusion. 2022;:1-8
Abstract
Repurposed drugs may reduce morbidity and mortality in patients with hematological disorders who develop COVID-19 illness. 112 patients with predominantly hematological illnesses were randomized to receive standard of care, ivermectin 12 mg [Iv 12] or 24 mg [Iv24] for asymptomatic, mild, or moderate COVID 19 illness. Serial respiratory samples for rRT-PCR samples were sent on Day 3, 5 and 7. rRT-PCR negativity and ≥ 2 log(10) reduction in viral loads on day 3, 5 and 7 were similar between the 3 treatment groups across all disease categories. Symptom progression occurred in 26 patients [21.6%] with no difference across 3 treatment groups. Twenty-two patients [18.3%] have expired while 98 [81.7%] survived. Survival rates were similar across treatment groups [controls-80.5%, Iv12-77.5%, Iv24-87.2% respectively]. Overall, poorer survival was seen with moderate illness compared to others [51.6% vs 92.1%; p = 0.000] and was the only significant risk factor identified on multivariate analysis. In this Phase II randomised trial, single dose of 12 or 24 mg of ivermectin did not reduce viral loads, prevent symptom progression, or reduce mortality in patients with predominantly haematological illnesses who develop mild to moderate COVID 19 illness.
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Treatment of severe COVID-19 patients with either low- or high-volume of convalescent plasma versus standard of care: A multicenter Bayesian randomized open-label clinical trial (COOP-COVID-19-MCTI)
Song ATW, Rocha V, Mendrone-Júnior A, Calado RT, De Santis GC, Benites BD, Costa-Lima C, Vargas T, Marques LS, Fernandes JC, et al
Lancet Regional Health. Americas. 2022;10:100216
Abstract
BACKGROUND Administration of convalescent plasma may serve as an adjunct to supportive treatment to prevent COVID-19 progression and death. We aimed to evaluate the efficacy and safety of 2 volumes of intravenous convalescent plasma (CP) with high antibody titers for the treatment of severe cases of COVID-19. METHODS We conducted a Bayesian, randomized, open-label, multicenter, controlled clinical trial in 7 Brazilian hospitals. Adults admitted to hospital with positive RT-PCR for SARS-CoV2, within 10 days of the symptom onset, were eligible. Patients were randomly assigned (1:1:1) to receive standard of care (SoC) alone, or in combination with 200 mL (150-300 mL) of CP (Low-volume), or 400 mL (300-600 mL) of CP (High-volume); infusion had to be performed within 24 h of randomization. Randomization was centralized, stratified by center. The primary outcome was the time until clinical improvement up to day 28, measured by the WHO ten-point scale, assessed in the intention-to-treat population. Interim and terminal analyses were performed in a Bayesian framework. Trial registered at ClinicalTrials.gov: NCT04415086. FINDINGS Between June 2, 2020, and November 18, 2020, 129 patients were enrolled and randomly assigned to SoC (n = 42), Low-volume (n = 43) or High-volume (n = 44) CP. Donors presented a median titer of neutralizing antibodies of 1:320 (interquartile range, 1:160 to 1:1088). No evidence of any benefit of convalescent plasma was observed, with Bayesian estimate of 28-day clinical improvement of 72.7% (95%CI, 58.8 to 84.7) in the SoC versus 64.1% (95%ci, 53.8 to 73.7) in the pooled experimental groups (mean difference of -8.7%, 95%CI, -24.6 to 8.2). There was one case of cutaneous mild allergic reaction related to plasma transfusion and one case of suspected transfusion-related acute lung injury but deemed not to be related to convalescent plasma infusion. INTERPRETATION In this prospective, randomized trial of adult hospitalized patients with severe COVID-19, convalescent plasma was not associated with clinical benefits. FUNDING Brazilian Ministry of Science, Technology and Innovation, Fundação de Amparo à Pesquisa do Estado de São Paulo.
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A phase 2 single center open label randomised control trial for convalescent plasma therapy in patients with severe COVID-19
Ray Y, Paul SR, Bandopadhyay P, D'Rozario R, Sarif J, Raychaudhuri D, Bhowmik D, Lahiri A, Vasudevan JS, Maurya R, et al
Nature communications. 2022;13(1):383
Abstract
A single center open label phase 2 randomised control trial (Clinical Trial Registry of India No. CTRI/2020/05/025209) was done to assess clinical and immunological benefits of passive immunization using convalescent plasma therapy. At the Infectious Diseases and Beleghata General Hospital in Kolkata, India, 80 patients hospitalized with severe COVID-19 disease and fulfilling the inclusion criteria (aged more than 18 years, with either mild ARDS having PaO2/FiO2 200-300 or moderate ARDS having PaO2/FiO2 100-200, not on mechanical ventilation) were recruited and randomized into either standard of care (SOC) arm (N = 40) or the convalescent plasma therapy (CPT) arm (N = 40). Primary outcomes were all-cause mortality by day 30 of enrolment and immunological correlates of response to therapy if any, for which plasma abundance of a large panel of cytokines was quantitated before and after intervention to assess the effect of CPT on the systemic hyper-inflammation encountered in these patients. The secondary outcomes were recovery from ARDS and time taken to negative viral RNA PCR as well as to report any adverse reaction to plasma therapy. Transfused convalescent plasma was characterized in terms of its neutralizing antibody content as well as proteome. The trial was completed and it was found that primary outcome of all-cause mortality was not significantly different among severe COVID-19 patients with ARDS randomized to two treatment arms (Mantel-Haenszel Hazard Ratio 0.6731, 95% confidence interval 0.3010-1.505, with a P value of 0.3424 on Mantel-Cox Log-rank test). No adverse effect was reported with CPT. In severe COVID-19 patients with mild or moderate ARDS no significant clinical benefit was registered in this clinical trial with convalescent plasma therapy in terms of prespecified outcomes.
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The anti-C5a antibody vilobelimab efficiently inhibits C5a in patients with severe COVID-19
Vlaar APJ, Lim EHT, de Bruin S, Rückinger S, Pilz K, Brouwer MC, Guo RF, Heunks LMA, Busch MH, van Paassen P, et al
Clinical and translational science. 2022
Abstract
Recently, we reported the phase II portion of the adaptive phase II/III PANAMO trial exploring potential benefit and safety of selectively blocking C5a with the monoclonal antibody vilobelimab (IFX-1) in patients with severe coronavirus disease 2019 (COVID-19). The potent anaphylatoxin C5a attracts neutrophils and monocytes to the infection site, causes tissue damage by oxidative radical formation and enzyme releases, and leads to activation of the coagulation system. Results demonstrated that C5a inhibition with vilobelimab was safe and secondary outcomes appeared in favor of vilobelimab. We now report the pharmacokinetic/pharmacodynamic (PK/PD) analysis of the phase II study. Between March 31 and April 24, 2020, 30 patients with severe COVID-19 pneumonia confirmed by real-time polymerase chain reaction were randomly assigned 1:1 to receive vilobelimab plus best supportive care or best supportive care only. Samples for measurement of vilobelimab, C3a and C5a blood concentrations were taken. Vilobelimab predose (trough) drug concentrations in plasma ranged from 84,846 to 248,592 ng/ml (571 to 1674 nM) with a geometric mean of 151,702 ng/ml (1022 nM) on day 2 and from 80,060 to 200,746 ng/ml (539 to 1352 nM) with a geometric mean of 139,503 ng/ml (939 nM) on day 8. After the first vilobelimab infusion, C5a concentrations were suppressed in the vilobelimab group (median 39.70 ng/ml 4.8 nM, IQR 33.20-45.55) as compared to the control group (median 158.53 ng/ml 19.1 nM, IQR 60.03-200.89, p = 0.0006). The suppression was maintained on day 8 (p = 0.001). The current PK/PD analysis shows that vilobelimab efficiently inhibits C5a in patients with severe COVID-19.
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Study of Alteplase for Respiratory Failure in SARS-CoV-2 COVID-19: A Vanguard Multicenter, Rapidly Adaptive, Pragmatic, Randomized Controlled Trial
Barrett CD, Moore HB, Moore EE, Wang J, Hajizadeh N, Biffl WL, Lottenberg L, Patel PR, Truitt MS, McIntyre RC Jr, et al
Chest. 2022;161(3):710-727
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BACKGROUND Pulmonary vascular microthrombi are a proposed mechanism of COVID-19 respiratory failure. We hypothesized that early administration of tissue plasminogen activator (tPA) followed by therapeutic heparin would improve pulmonary function in these patients. RESEARCH QUESTION Does tPA improve pulmonary function in severe COVID-19 respiratory failure, and is it safe? STUDY DESIGN AND METHODS Adults with COVID-19-induced respiratory failure were randomized from May14, 2020 through March 3, 2021, in two phases. Phase 1 (n = 36) comprised a control group (standard-of-care treatment) vs a tPA bolus (50-mg tPA IV bolus followed by 7 days of heparin; goal activated partial thromboplastin time [aPTT], 60-80 s) group. Phase 2 (n = 14) comprised a control group vs a tPA drip (50-mg tPA IV bolus, followed by tPA drip 2 mg/h plus heparin 500 units/h over 24 h, then heparin to maintain aPTT of 60-80 s for 7 days) group. Patients were excluded from enrollment if they had not undergone a neurologic examination or cross-sectional brain imaging within the previous 4.5 h to rule out stroke and potential for hemorrhagic conversion. The primary outcome was Pao(2) to Fio(2) ratio improvement from baseline at 48 h after randomization. Secondary outcomes included Pao(2) to Fio(2) ratio improvement of > 50% or Pao(2) to Fio(2) ratio of ≥ 200 at 48 h (composite outcome), ventilator-free days (VFD), and mortality. RESULTS Fifty patients were randomized: 17 in the control group and 19 in the tPA bolus group in phase 1 and eight in the control group and six in the tPA drip group in phase 2. No severe bleeding events occurred. In the tPA bolus group, the Pao(2) to Fio(2) ratio values were significantly (P < .017) higher than baseline at 6 through 168 h after randomization; the control group showed no significant improvements. Among patients receiving a tPA bolus, the percent change of Pao(2) to Fio(2) ratio at 48 h (16.9% control [interquartile range (IQR), -8.3% to 36.8%] vs 29.8% tPA bolus [IQR, 4.5%-88.7%]; P = .11), the composite outcome (11.8% vs 47.4%; P = .03), VFD (0.0 [IQR, 0.0-9.0] vs 12.0 [IQR, 0.0-19.0]; P = .11), and in-hospital mortality (41.2% vs 21.1%; P = .19) did not reach statistically significant differences when compared with those of control participants. The patients who received a tPA drip did not experience benefit. INTERPRETATION The combination of tPA bolus plus heparin is safe in severe COVID-19 respiratory failure. A phase 3 study is warranted given the improvements in oxygenation and promising observations in VFD and mortality. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT04357730; URL: www. CLINICALTRIALS gov.