CI

At a glance

ClinicalIndex Comparison Record
Phase 2Completed· 168 enrolled
Drug / intervention
Nirmatrelvir +2 moredrug
Likely dose
Nirmatrelvir 150 mgfrom record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT05576662
NCT05576662Phase 2Completed
CompareCT.gov

Selective Trial Of Paxlovid for PASC (STOP-PASC): Randomized Double-Blind Placebo-Controlled Pilot Trial of Paxlovid for the Treatment of PASC

Stanford University·interventional·Posted Oct 12, 2022·Updated Sep 4, 2025

In Brief

A Phase 2 clinical trial evaluating Nirmatrelvir, Placebo, and 1 other intervention for Post-acute Sequelae of SARS-CoV-2 Infection and Long COVID. Completed, enrolled 168 participants across 1 site.

Detailed Summary

The purpose of this study is to compare whether being treated with nirmatrelvir plus ritonavir for 15 days works better than being treated with placebo plus ritonavir to reduce severe symptoms of Long Covid. Participants will have 5 planned visits to the study clinic over 15 weeks and will take the drug (or placebo) for the first 15 days. This study uses the term post-acute sequelae of SARS-CoV-2 (PASC), which is another name for "Long Covid."

Study Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
ConditionsPost-acute Sequelae of SARS-CoV-2 Infection, Long COVID
CountriesUnited States
CollaboratorsPfizer

Timeline

Phase 2CompletedFinished
2023202420252026
First PostedOct 12, 2022
Enrollment StartNov 8, 2022
Primary CompletionAug 14, 2023
Study CompletionSep 12, 2023
TodayJul 2, 2026
Enrollment to primary: 9 monthsPosted 3.7 years ago

Interventions

Nirmatrelvirdrug

Two 150 mg tablets taken by mouth every 12 hours

Placebodrug

Two tablets containing placebo matching nirmatrelvir taken by mouth every 12 hours

Ritonavirdrug

One 100 mg capsule taken by mouth every 12 hours