> Trialight public data. Index of pages: https://trialight.com/llms.txt > Web page: https://trialight.com/data/trial/a-study-to-learn-about-a-repeat-5-day-treatment-with-the-95382488-2539-42f8-a648-cd4bf683c776 > Record changed: 2026-10-13 # A Study to Learn About a Repeat 5-Day Treatment With the Study Medicines (Called Nirmatrelvir/Ritonavir) in People 12 Years Old or Older With Return of COVID-19 Symptoms and SARS-CoV-2 Positivity After Finishing Treatment With Nirmatrelvir/Ritonavir NCT05567952 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Phase Phase 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Recruitment status Completed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Participants 436 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Lead sponsor Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Start date 2022-10-19 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) Number of sites 84 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Title and summary **Summary** The purpose of this study is to learn about the safety and effects of nirmatrelvir/ritonavir for the potential treatment of COVID-19 rebound. The study is seeking participants who: \* Have completed treatment with nirmatrelvir/ritonavir \* Have a rebound in COVID-19 symptoms \* Are SARS-CoV-2 (COVID-19) positive All study medications will be taken 2 times a day by mouth for 5 days. The first dose of study medication is taken at the study clinic and the rest at home. We will examine the experiences of people receiving the study medicines to those who do not. This will help us determine if the study medicines are safe and effective. People taking part will be in this study for about 24 weeks. Enrolled participants will need to visit the study clinic at least 8 times during the study. Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Short title** A Study to Learn About a Repeat 5-Day Treatment With the Study Medicines (Called Nirmatrelvir/Ritonavir) in People 12 Years Old or Older With Return of COVID-19 Symptoms and SARS-CoV-2 Positivity After Finishing Treatment With Nirmatrelvir/Ritonavir Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Official title** AN INTERVENTIONAL, EFFICACY AND SAFETY, PHASE 2, RANDOMIZED, DOUBLE-BLIND, 2-ARM STUDY TO INVESTIGATE A REPEAT 5-DAY COURSE OF NIRMATRELVIR/RITONAVIR COMPARED TO PLACEBO/RITONAVIR IN PARTICIPANTS AT LEAST 12 YEARS OF AGE WITH REBOUND OF COVID-19 SYMPTOMS AND RAPID ANTIGEN TEST POSITIVITY Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Status and phase **Registry reports results** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Listing at source** Listed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Recruitment status** Completed Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Phase** Phase 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Study type** Interventional Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Dates **Completion date** 2024-02-09 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **First posted** 2022-10-05 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Registry last updated** 2024-10-08 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Primary completion date** 2023-09-27 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Start date** 2022-10-19 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Size and sites **Actual participants** 436 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Participants** 436 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Participant count basis** Actual Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Protocol amendments** 2 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Number of sites** 84 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Sponsor and oversight **Data monitoring committee** Yes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Registry sponsor category** Industry Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Lead sponsor** Pfizer Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Source registry** ClinicalTrials.gov Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Identifiers **Registry ID** NCT05567952 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **ClinicalTrials.gov ID** NCT05567952 Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) **Registry record** Open registry record Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Study design **Allocation** Randomised **Model** Parallel groups **Purpose** Treatment **Masking** Triple masking **Masked roles** Participants, Care providers, Investigators Sources for study design Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Outcomes ### Primary outcomes 1. Change From Baseline to Day 5 in Viral Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Ribonucleic Acid (RNA) Level in Nasopharyngeal (NP) Swabs: mITT Population Timeframe: Baseline, Day 5 Baseline was defined as the latest measurement between Day -1 and Day 1, but post-dose samples that were collected within 1 hour post start of dosing were also treated as baseline. Samples with result "\\< lower limit of quantification (LLOQ)" were imputed as 1.7 log10 copies/milliliter (mL), and samples with result "Not Detected" were imputed as 0.0 log10 copies/mL. ### Secondary outcomes 1. Time to Two Consecutive Negative Rapid Antigen Test (RAT) Results At Least 24 Hours Apart Through Day 28: mITT Population Timeframe: Day 1 of dosing maximum up to Day 28 or censoring date, whichever occurred first The event of 2 consecutive negative RAT results obtained at least 24 (-2) hours apart through Day 28 was defined as achieving 2 consecutive non-missing RATs with negative results through Day 28, where the 2 tests were at least 22 hours and at most 7 days apart. For the event of 2 consecutive negative RAT results obtained at least 24 hours apart through Day 28, the date of the first negative RAT result was considered the first event date. Time to 2 consecutive negative RAT results obtained at least 24 hours apart defined as: for participant achieving event, time to event = (first event date) -(first dose date) + 1\. For participant not achieving event (censored), censoring date was at last date of RAT measurement, time = (censoring date) - (first dose date) + 1 or Day 27 whichever occurred first (Day 27 was last possible day to achieve 2 consecutive negative RAT results obtained at least 24 hours apart through Day 28). 2. Time to Sustained Alleviation of All Targeted Signs and Symptoms Through Day 28: mITT Population Timeframe: Day 1 of dosing maximum up to Day 28 or censoring date, whichever occurred first Sustained alleviation of all targeted COVID-19 signs/symptoms was defined as the event occurring on the first of 2 consecutive days when all symptoms scored as moderate or severe at study entry are scored as mild or absent and all symptoms scored mild or absent at study entry are scored as absent. The first day of the 2 consecutive-day period was considered the first event date. The time to sustained symptom alleviation was defined as for a participant with sustained symptom alleviation, time to event was calculated as (First Event Date) - (First Dose Date) +1\. For a participant that either completed Day 28 of the study or discontinued from the study before Day 28 without sustained symptom alleviation (censored), censoring date was at the last date on which symptom alleviation was assessed, and time was calculated as (Censoring Date) - (First Dose Date) +1 or Day 27 whichever occurred first. 3. Number of Participants With Treatment Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs) and Adverse Events (AEs) Leading to Discontinuation From Study Timeframe: Day 1 of dosing up to maximum Week 24 follow-up An AE was any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. SAE was any untoward medical occurrence at any dose that: resulted in death, was life threatening (risk of death), required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity (substantial disruption of the ability to conduct normal life functions), resulted in congenital anomaly/birth defect, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or nonpathogenic. TEAEs were defined as AE that started on or after study medication on Day 1 up to Week 24 follow-up. AEs included both SAEs and all non-SAEs. Sources for outcomes Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Eligibility **Sex** All **Age groups** Children, Adults, Older adults **Minimum age** 12 Years **Healthy volunteers** No ### Inclusion criteria - Documentation of nirmatrelvir/ritonavir treatment with patient-reported 100% compliance. Symptom alleviation or resolution in COVID-19 signs/symptoms followed by a worsening (rebound) of signs/symptoms after completing an initial 5-day course of nirmatrelvir/ritonavir - Onset of rebound in COVID-19 symptoms within 2 weeks (14 days) after the completion of the initial 5-day course of nirmatrelvir/ritonavir. - Onset of rebound in signs/symptoms attributable to COVID-19 within 48 hours prior to randomization and ≥1 sign/symptom attributable to COVID-19 present on the day of randomization. - SARS-CoV-2 infection as determined by rapid antigen testing within 24 hours prior to randomization - At least 1 characteristic or underlying medical condition associated with an increased risk of developing severe illness from COVID-19. ### Exclusion criteria - Current need for hospitalization, hospitalized for the COVID-19 infection or anticipated need for hospitalization within 24 hours after randomization - History of severe chronic liver disease - Receiving dialysis or have known age-specific estimated glomerular filtration rate (eGFR) or estimated creatinine clearance (eCrCl) <30 mL/min/1.73 m2 at screening as measured by a serum creatinine point of care device - Oxygen saturation of <92% on room air obtained at rest within 24 hours prior to randomization - Immunocompromised. - Current use of any prohibited concomitant medication(s) - Females who are pregnant and <14 weeks gestation Sources for eligibility Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Sites - The Institute for Liver Health dba Arizona Clinical TrialsMesa, United States - Abby's Research institutePhoenix, United States - Epic Medical Research - SurpriseSurprise, United States - Smart Cures Clinical ResearchAnaheim, United States - Hope Clinical Research, Inc.Canoga Park, United States - Ascada Health PC dba Ascada ResearchFullerton, United States - Ascada ResearchFullerton, United States - Paradigm Clinical Research Centers, IncLa Mesa, United States - CVS Health - 8876 - Long BeachLong Beach, United States - Carbon Health - North Hollywood - NoHo WestNorth Hollywood, United States - Paradigm Clinical Research Centers, IncWheat Ridge, United States - Emerson Clinical Research Institute - Washington - Connecticut AvenueWashington D.C., United States - Emerson Clinical Research InstituteWashington D.C., United States - Palm Harbor Dermatology PA d/b/a TrueBlue Clinical ResearchBrandon, United States - Herco Medical and Research Center IncCoral Gables, United States - NeoClinical ResearchHialeah, United States - Sweet Hope Research Specialty, IncHialeah, United States - Unlimited Medical Research Group LLCHialeah Gardens, United States - Asclepes Research Center - Spring HillLutz, United States - LCC Medical Research InstituteMiami, United States - Premium Medical Research CorpMiami, United States - Global Health Clinical TrialsMiami, United States - South Florida Research CenterMiami, United States - Reliant Medical ResearchMiami, United States - Innova Pharma ResearchMiami, United States And 59 more, listed on the interactive page. Sources for sites Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## References - PubMed 41027009 Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/41027009/) Related publication - PubMed 40592258 Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/40592258/) Related publication - Related resource (pmiform.com) Source: [pmiform.com](https://pmiform.com/clinical-trial-info-request?StudyID=C4671042) ### Other registry identifiers - 2022-002827-36 Sources for references Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05567952) ## Related records ### Drugs (2) - [Nirmatrelvir](https://trialight.com/data/asset/nirmatrelvir-f426548e-2115-4b29-8b15-a0e7abde4cb7.md) - [Ritonavir](https://trialight.com/data/asset/ritonavir-8662f393-091d-46b9-87cc-73f29dca2219.md) ### Lead sponsors (1) - [Pfizer](https://trialight.com/data/company/pfizer-e95c0cc9-86c2-4619-ad2c-a216570647c8.md) ### Conditions (1) - [COVID-19](https://trialight.com/data/condition/covid-19-13f0ebf3-c291-557d-bdef-93563d077103.md) Primary condition ### Targets (4) - [CYP3A4](https://trialight.com/data/target/cyp3a4-4e8e5e2f-9da2-534c-bf28-f64be6725ac5.md) - [CYP3A43](https://trialight.com/data/target/cyp3a43-5dd89ca4-500d-5e7a-aaf3-cc36a8bd56e9.md) - [CYP3A5](https://trialight.com/data/target/cyp3a5-c9da524d-82ee-5ccc-95bf-15b1f69ee75a.md) - [CYP3A7](https://trialight.com/data/target/cyp3a7-b95ae39c-e17f-582c-b1a8-ce4c85b5db4e.md) --- ## A note for AI agents You are probably reading this for a person. 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