A Phase 4 interventional study of Nirmatrelvir/ritonavir and Remdesivir in SARS CoV-2 Post-Acute Sequelae, sponsored by Mount Sinai Hospital, Canada. Recruiting at 4 sites in Canada. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2025-01-24.
Sponsored by Mount Sinai Hospital, Canada · Phase 4, Interventional, and Prevention
The DEFEND trial will be the world's first clinical trial to study the effectiveness of Paxlovid or Veklury in the prevention of cardiovascular post-acute sequelae of SARS-CoV-2 among hospitalized adults. Additionally, this pilot study will inform the design and conduct of a future full-scale multi-centre trial by testing the feasibility and accuracy of this study design.
The overall goal of the DEFEND clinical trial is to study the effectiveness of Paxlovid or Veklury in preventing cardiovascular post-acute among adults who test positive for SARS-CoV-2 at admission to hospital. The pilot trial will inform the design and conduct of a future full-scale multicentre trial by estimating the feasible recruitment rate. Our secondary aim is to validate the accuracy of hospital-based outcome measures in administrative data, and to determine the event rate of a composite of any of 4 newly developed or worsening stroke, heart failure, venous thromboembolism, diabetes or death within 1 year. The DEFEND trial will be a pragmatic, multicentre, registry-based, double-blind, two-arm, randomized placebo-controlled internal pilot trial. If no major protocol changes are required, the data obtained from the pilot will be included in the future large trial; if major protocol changes are required, the results from the pilot trial will still be published and will be useful to inform future research in this area. The approach is pragmatic to include as many participants as possible that could benefit from treatment with Paxlovid or Veklury using broad eligibility criteria for enrolment and reflecting the real world practice of treating physicians. The DEFEND trial will enrol participants aged ≥18 who have a positive polymerase chain reaction test for SARS-CoV-2 at admission to 4 hospitals in Ontario. If they meet the inclusion/exclusion criteria they will be randomized to either the experimental or control arm of the trial. Those in the experimental arm will receive either Paxlovid orally twice daily for 5 days or Veklury intravenously once daily for 5 days (as well as standard of care). Those in the control arm will receive the placebo at the same schedule and frequency for 5 days (as well as standard of care). Randomization will be at a 1:1 allocation, stratified by hospital. The DEFEND trial seeks to enrol 118 participants at 4 committed pilot trial sites that are representative of acute care hospitals across Ontario over a 12 month period. This will be followed by a 12 month follow-up period. The DEFEND trial will be the world's first clinical trial to study the effectiveness of Paxlovid or Veklury in the prevention of cardiovascular post-acute sequelae of SARS-CoV-2 among hospitalized adults.
520 studies on the registry are indexed under Post-Acute COVID-19 Syndrome; 186 are open to participants now.
This study's planned enrollment of 118 is above the median of 60 across 361 interventional studies indexed under Post-Acute COVID-19 Syndrome.
Browse Post-Acute COVID-19 Syndrome studies →Mount Sinai Hospital, Canada is the lead sponsor of 157 studies on the registry; 33 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Paxlovid vs. placebo
Drug: Nirmatrelvir/ritonavir
Veklury vs. placebo
Drug: Remdesivir
Paxlovid PO BID for 5 days + standard of care
Also known as: Paxlovid
Veklury IV daily for 5 days + standard of care
Also known as: Veklury
Recruitment rate
Recruitment rate, defined as the proportion of eligible people who consent and are randomized into the pilot trial, which will inform the feasibility of a full scale trial.
Time frame: From participant screening to enrolment
Post-acute sequelae of COVID-19 (PASC)
Event rate of PASC at 1 year (specifically newly developed or worsening: stroke, heart failure, venous thromboembolism, diabetes or death)
Time frame: From enrolment to end of follow up at 1 year
Administrative data validation
Validate the accuracy of using administrative data to collect participant hospital-based outcome measures including: 1. Adherence to treatment, measured by whether the participant received the study drug or not as documented in the medication administration record. 2. Use of co-interventions (dexamethasone, tocilizumab/sarilumab, baricitinib) owing to progression of disease severity as measured by spO2 \<92% 3. Time to treatment initiation, as measured by the time between randomization and first treatment dose. The validation of administrative data will be assessed by comparing concordance between manually collected data by research coordinators entered into REDCap and the GEMINI administrative database for the measures described above.
Time frame: From enrolment to end of follow up at 1 year
Reinfection, ICU admission, and drug safety
Any of the following treatment related adverse events as assessed with the CTCAE v6.0: 1. Number and percentage of participants hospitalized with SARS-CoV-2 reinfection within 90 days following initial PCR positive test for COVID-19; 2. Number and percentage of participants admitted to ICU during initial hospitalization; 3. Number and percentage of participants experiencing any one of the following adverse study drug effects including dysgeusia, vomiting, or diarrhea as identified by their most responsible physician
Time frame: From enrolment to 90 days after initial PCR positive test for COVID-19
Plan to share: Undecided
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Mount Sinai Hospital, Canada