# 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** · PHASE2 · COMPLETED · sponsor: **Pfizer** · enrollment: 436 (actual)

## Conditions studied

- COVID-19

## Interventions

- **DRUG:** nirmatrelvir
- **DRUG:** ritonavir
- **DRUG:** placebo for nirmatrelvir

## Key facts

- **NCT ID:** NCT05567952
- **Lead sponsor:** Pfizer
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** COMPLETED
- **Start date:** 2022-10-19
- **Primary completion:** 2023-09-27
- **Final completion:** 2024-02-09
- **Target enrollment:** 436 (ACTUAL)
- **Last updated:** 2024-10-08


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT05567952

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT05567952, "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". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT05567952. Licensed CC0.

---

*[Clinical trials dataset](/datasets/clinical-trials) · CC0 1.0*