-Author name in bold denotes the presenting author
-Asterisk * with author name denotes a Non-ASH member
Clinically Relevant Abstract denotes an abstract that is clinically relevant.

PhD Trainee denotes that this is a recommended PHD Trainee Session.

Ticketed Session denotes that this is a ticketed session.

133 Anticoagulation and Antiplatelet Strategies in Non-Critically Ill Patients with Covid-19Clinically Relevant Abstract

Program: Oral and Poster Abstracts
Type: Oral
Session: 331. Thrombotic Microangiopathies/Thrombocytopenias and COVID-19-related Thrombotic/Vascular Disorders: Clinical and Epidemiological I
Hematology Disease Topics & Pathways:
Research, clinical trials, Anticoagulant Drugs, Non-Biological therapies, Clinical Research, Therapies
Saturday, December 10, 2022: 12:00 PM

Zoe McQuilten, MBBS, PhD1,2*, Balasubramanian Venkatesh, MD3,4*, Vivekanand Jha, MD5,6*, Jason Roberts, PhD3*, Susan Morpeth, PhD7*, James Totterdell, MBiostat8*, Grace McPhee, PhD9*, John Abraham, MBBS10*, Niraj Bam, MD11*, Methma Bandara, BH-BMED9*, Ashpak Bangi, MD12*, Lauren Barina, MBE13*, Bhupendra Basnet, MD14*, Hasan Bhally, MD15*, Khemr Bhusal, MD16*, Umesh Bogati, MD14*, Asha Bowen, PhD17,18*, Andrew Burke, MBBS3,19*, Devasahayam Christopher, MD20*, Sanjeev Chunilal, FRACP21*, Belinda Cochrane, MD22,23*, Jennifer Curnow, MBBS FRACP FRCPA PhD24,25*, Varaprasad Babu Dara Reddy, MD26*, Santa Das, MD16*, Ashesh Dhungana, MD, DM14*, Gian Luca Di Tanna, PhD4*, Ravindra Dotel, MBBS27*, Hyjel DSouza, BSc28*, Jack Dummer, PhD29,30*, Sourabh Dutta, PhD31*, Hong Foo, MBBS32*, Timothy Gilbey, MBBS33*, Michelle Giles, PhD9*, Kasiram Goli, MD34*, Adrienne Gordon, PhD8,35*, Pradip Gyanwali, MD36*, Bernard Hudson, MD32*, Manoj Jani, MBBS37*, Purnima Jevaji, MDHA5*, Sachin Jhawar, MS37*, Aikaj Jindal, MD38*, M. Joseph John, MD, DM39, Mary John, MD10*, Flavita John, MBBS20*, Oommen John, MD5*, Mark Jones, MBiostat8*, Rajesh Joshi, BHMS5*, Prashanthi Kamath, MPH5*, Gagandeep Kang, MD, PhD20*, Achyut Karki, MDGP14*, Abhishek Karmalkar, MD4*, Baldeep Kaur, MIS4*, Kalyan Chakravarthy Koganti, MD26*, Jency Koshy, MD40*, S K Mathew, MD40*, Jilllian Lau, PhD41*, Sharon Lewin, PhD9,42*, Lyn-li Lim, MPH42*, Ian Marschner, PhD8*, Julie Marsh, PhD17*, Michael Maze, PhD29*, James McGree, PhD43*, James McMahon, PhD42*, Robert Medcalf, PhD44*, Eileen Merriman, MD, PhD45*, Amol Misal, MD46*, Jocelyn Mora, MSc9*, Vijaybabu Mudaliar, MSc5*, Vi Nguyen, BH-BMED9*, Matthew O'Sullivan, PhD47*, Suman Pant, MBBS16*, Pankaj Pant, MBBS16*, David Paterson, MBBS48*, David Price, PhD9*, Megan Rees, MBBS, PhD49*, James Owen Robinson, MD50*, Benjamin Rogers, PhD51*, Sandhya Samuel, MD10*, Joe Sasadeusz, PhD9,49*, Deepak Sharma, MBBS52*, Prabhat Sharma, MD52*, Roshan Shrestha, MD14*, Sailesh Shrestha, MD14*, Prajowl Shrestha, MD53*, Urvi Shukla, MD53*, Omar Shum, MSc54*, Christine Sommerville, BH-SCI9*, Tim Spelman, PhD55*, Richard Sullivan, MBBS56*, Umashankar Thatavarthi, MD26*, Huyen Tran, MD, PhD57*, Nanette Trask58*, Claire Whitehead, PhD59*, Robert Mahar, PhD60*, Naomi Hammond, PhD4*, James David McFadyen, PhD61,62*, Thomas Snelling, PhD8,17*, Joshua Davis, PhD56,63*, Justin Denholm, PhD9* and Steven YC Tong, PhD9,49*

1School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia
2Monash Health, Melbourne, Australia
3University of Queensland, Brisbane, Australia
4The George Institute for Global Health, Sydney, Australia
5The George Institute for Global Health, New Delhi, India
6Imperial College, London, United Kingdom
7Middlemore Hospital, Auckland, New Zealand
8University of Sydney, Sydney, Australia
9The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia
10Christian Medical College, Ludhiana, India
11Maharajgunj Medical Campus, Kathmandu, Nepal
12Jivanrekha Multispeciality Hospital, Pune, India
13The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melburne, Australia
14National Academy of Medical Sciences, Bir Hospital, Kathmandu, Nepal
15North Shore Hospital, Auckland, New Zealand
16Institute of Medicine, Tribhuvan University Teaching Hospital, Kathmandu, Nepal
17Wesfarmers Centre for Vaccines and Infectious Diseases, Telethon Kids Institute, University of Western Australia, Perth, Australia
18Perth Children's Hospital, Perth, Australia
19The Prince Charles Hospital, Brisbane, Australia
20Christian Medical College, Vellore, India
21Monash Health, Melbourne, AUS
22Campbelltown Hospital, Sydney, Australia
23Western Sydney University, Sydney, Australia
24Department of Haematology, Westmead Hospital, Western Sydney Local Health District, Sydney, Australia
25Faculty of Health and Medicine, University of Sydney, Sydney, NSW, Australia
26Samishta Hospital & Research Institute, Guntur, India
27Blacktown Hospital, Sydney, Australia
28The George Institute for Global Health, Delhi, India
29University of Otago, Dunedin, New Zealand
30Dunedin Hospital, Dunedin, New Zealand
31Postgraduate Institute of Medical Education and Research, Chandigarh, India
32NSW Health Pathology, Sydney, Australia
33Wagga Wagga Base Hospital, Wagga Wagga, Australia
34Aditya Multi-speciality Hospital, Guntur, India
35Royal Prince Alfred Hospital, Sydney, Australia
36Institute of Medicine, Maharajgunj Medical Campus, Kathmandu, Nepal
37Apex Hospitals Pvt Ltd, Jaipur, India
38Satguru Partap Singh Hospitals, Ludhiana, India
39Department of Clinical Haematology and BMT, Christian Medical College & Hospital, Ludhiana, India
40Believers Church Medical College Hospital, Thiruvalla, India
41Eastern Health, Melbourne, Australia
42Monash University, Melbourne, Australia
43Queensland University of Technology, Brisbane, Australia
44Monash, Melbourne, AUS
45North Shore Hospital, Auckland, AL, NZL
46Core Hospital, Pune, India
47Westmead Hospital, Sydney, Australia
48National Institute of Singapore, Singapore, Singapore
49The Royal Melbourne Hospital, Melbourne, Australia
50Murdoch University, Perth, Australia
51Monash University, Clayton, Victoria, AUS
52Maharaja Agrasen Superspeciality Hospital, Jaipur, India
53Symbiosis University Hospital & Research Centre, Pune, India
54The Wollongong Hospital, Wollongong, Australia
55Burnet Institute, Melbourne, AUS
56Charles Darwin University, Darwin, Australia
57Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia
58Chartered Accountants Australia and New Zealand, Perth, Australia
59The Royal Women's Hospital, Melbourne, Australia
60The University of Melbourne, Melbourne, Australia
61Atherothrombosis and Vascular Biology, Baker Heart and Diabetes Institute, Melbourne, Australia
62Alfred Hospital, Melbourne, Australia
63University of Newcastle, Newcastle, Australia


Optimal thromboprophylaxis for hospitalized patients with Covid-19 is uncertain. Most published clinical trials comparing different anticoagulation protocols in hospitalized patients with Covid-19 have recruited patients in high-income countries (HIC) and results may not be generalizable to patients in low and middle-income countries (LMIC). Furthermore, the incidence of VTE varies by ethnic background with higher rates reported amongst Caucasian compared to diverse Asian populations. We report the results of an international (incorporating both HIC and LMIC regions) adaptive platform randomized trial in hospitalized non-critically ill patients with Covid-19 comparing the effectiveness of low-dose, intermediate-dose, therapeutic-dose anticoagulation, and low-dose plus aspirin on survival and need for organ support.


The Australasian COVID-19 Trial (ASCOT) is an investigator-initiated, open-label, pragmatic adaptive platform randomized clinical trial of therapeutics (anticoagulation, antiviral, and therapeutic antibody domains) for non-critically ill patients hospitalized with Covid-19. In our anticoagulation trial, we initially randomly assigned patients to low-dose low-molecular-weight heparin (LMWH) thromboprophylaxis, intermediate-dose or low-dose plus aspirin. In response to external evidence, the aspirin intervention was discontinued and a therapeutic-dose arm added. The primary endpoint was death or the requirement for new organ support by day-28, analyzed with a Bayesian logistic model. Enrolment was closed due to operational constraints.


Between February 2021 and April 2022, we screened 2,203 patients in 32 hospitals (15 in Australia, 4 in New Zealand, 11 in India, and 2 in Nepal) and enrolled 1574 into the anticoagulation domain (619 assigned to low-dose, 620 to intermediate-dose, 285 to low dose plus aspirin, and 50 to therapeutic-dose). Eighteen participants withdrew consent and 30 were lost to follow-up leaving 1526 included in the primary analysis population (1273 from India, 138 from Australia and New Zealand, 115 from Nepal).

The median age of participants was 49 years, 633 (41%) were female, 1291 (83%) were Indian, 480 (31%) were vaccinated against SARS-CoV-2, and 629 (40%) had one or more comorbidities. Adherence to the trial protocol was 98% in the low-dose, 98% in the intermediate-dose, 97% in the low-dose plus aspirin and 92% in the therapeutic-dose anticoagulation arms. All participants received enoxaparin except for one participant in the intermediate group who received tinzaparin.

At 28 days after randomization, 35/596 (5.9%) participants assigned to low-dose, 25/601 (4.2%) intermediate-dose, 20/279 (7.2%) low-dose plus aspirin, and 7/50 (14%) therapeutic-dose anticoagulation had died or required organ support. Compared to low-dose thromboprophylaxis, the median adjusted odds ratio (aOR) for the primary outcome for intermediate-dose was 0.74 (95% credible interval [CrI] 0.43 to 1.27, posterior probability of effectiveness [aOR < 1] [Pr] 86%), for low-dose plus aspirin 0.88 (95% CrI 0.47 to 1.64, Pr 65%) and for therapeutic-dose 2.22 (95% CrI 0.77 to 6.20, Pr 7%). The results were consistent in a number of sensitivity analyses including when restricting the analysis populations to concurrent randomizations. The results were also broadly consistent across the predefined subgroups, with the posterior probability of effectiveness for intermediate-dose compared to low-dose ranging from 56% (corticosteroid exposure) to 94% (>7 days of symptom onset to hospitalization). Overall thrombotic and bleeding rates were 0.8% and 0.4%, respectively.


In hospitalized adults with Covid-19, compared to low-dose, there was an 86% posterior probability that intermediate-dose, and 7% posterior probability that therapeutic-dose, reduced the odds of death or requirement for organ support by day 28. No treatment strategy met pre-specified statistical stopping criteria prior to trial closure.

Trial registration number: NCT04483960

Disclosures: McQuilten: Abbvie: Research Funding; Beigene: Research Funding; CSL: Research Funding; BMS/Celgene: Research Funding; GSK: Research Funding; Janssen: Research Funding; Novartis: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; Amgen: Research Funding. Jha: GSK: Research Funding; Baxter Health: Research Funding; Biocon: Research Funding; Bayer: Honoraria; AstraZeneca: Honoraria; Boeringer Ingelheim: Honoraria; NephroPlus: Honoraria; Zydus Cadilla: Honoraria. Roberts: Gilead: Consultancy; Summit: Consultancy; Pfizer: Consultancy, Research Funding, Speakers Bureau; Sandoz: Consultancy; MSD: Consultancy, Speakers Bureau; Cipla: Speakers Bureau; Biomerieux: Research Funding; QPEX: Research Funding. Lewin: Gilead: Honoraria, Research Funding, Speakers Bureau; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Viiv: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Vaxxinity: Membership on an entity's Board of Directors or advisory committees; Immunocore: Membership on an entity's Board of Directors or advisory committees; Esfam: Membership on an entity's Board of Directors or advisory committees. Sasadeusz: Gilead: Honoraria; GSK: Honoraria; AstraZeneca: Honoraria; Merck: Honoraria. Tran: Sanofi: Research Funding; AstraZeneca, CSL Behrig: Honoraria; Pfizer, Takeda: Speakers Bureau.

Previous Abstract | Next Abstract >>
*signifies non-member of ASH