# A Study to Learn About the Effects of Sisunatovir in Infants With Respiratory Syncytial Virus Lower Respiratory Tract Infection.

> **NCT04225897** · PHASE2 · TERMINATED · sponsor: **Pfizer** · enrollment: 51 (actual)

## Conditions studied

- Respiratory Syncytial Virus (RSV)
- Lower Resp Tract Infection

## Interventions

- **DRUG:** RV521
- **DRUG:** Placebo

## Key facts

- **NCT ID:** NCT04225897
- **Lead sponsor:** Pfizer
- **Sponsor class:** INDUSTRY
- **Phase:** PHASE2
- **Study type:** INTERVENTIONAL
- **Status:** TERMINATED
- **Start date:** 2019-11-13
- **Primary completion:** 2022-12-05
- **Final completion:** 2022-12-05
- **Target enrollment:** 51 (ACTUAL)
- **Why stopped:** Part A and Part B were completed but Pfizer terminated Part C due to strategic consideration. There were no safety concerns in the decision to stop Part C and no changes to the risk-benefit for participants who received RV521 in the study.
- **Last updated:** 2024-10-23


## Primary source

ClinicalTrials.gov registry: https://clinicaltrials.gov/study/NCT04225897

## Citation

> US National Library of Medicine, ClinicalTrials.gov registration NCT04225897, "A Study to Learn About the Effects of Sisunatovir in Infants With Respiratory Syncytial Virus Lower Respiratory Tract Infection.". Retrieved via AI Analytics 2026-06-02 from https://api.ai-analytics.org/clinical/NCT04225897. Licensed CC0.

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