Respiratory Syncytial Virus InfectionsPhase 2NCT03258502
A Study to Learn About the Effects of Multiple Doses of Sisunatovir on People With Respiratory Syncytial Virus (RSV) Infection
A Phase 2 study testing RV521 in people with Respiratory Syncytial Virus Infections, run by Pfizer at 1 site in United Kingdom.
Trial summary
The purpose of the study is to learn about the safety, pharmacokinetics and antiviral activity of the study medicine (called sisunatovir/RV521) for the potential treatment of respiratory syncytial virus (RSV). Sisunatovir will be given as multiple doses during the treatment period. Read more about this study
- Who is it for?
- Ages 18 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Respiratory Syncytial Virus Infections
- What is being tested?
- RV521
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 66 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 19 Jul 2017to 31 Oct 2017
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Age 18 to 45 years, inclusive
- In good health with no history of major medical conditions
- A total body weight ≥ 50 kg and a body mass index (BMI) of >/=18kg/m2 and </=30kg/m2
Who cannot join
- Evidence of any clinically significant or currently active major medical condition
- Positive for Human Immunodeficiency Virus, active Hepatitis A, B or C test
- Significant nose or nasopharynx abnormalities
- Abnormal lung function
- History or currently active symptoms suggestive of upper or lower respiratory tract infection
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Randomised, Phase 2a, Double-Blind, Placebo-Controlled Study To Evaluate The Safety, Pharmacokinetics And Antiviral Activity Of Multiple Doses Of RV521 Against Respiratory Syncytial Virus Infection In The Virus Challenge Model
The purpose of the study is to learn about the safety, pharmacokinetics and antiviral activity of the study medicine (called sisunatovir/RV521) for the potential treatment of respiratory syncytial virus (RSV). Sisunatovir will be given as multiple doses during the treatment period. RSV is a highly contagious virus that can lead to serious lung infections in patients with reduced ability to fight infection. Most vulnerable populations include babies, the elderly and patients that have received a bone marrow transplant.
This study is seeking healthy participants who are:
- Aged 18 to 45 years old and will agree to the use of highly effective methods of contraception.
- with a body mass index (BMI) of 18.0 to 30.0 Kg/m2 This study will consist of 2 cohorts of 33 participants each. In both cohorts participants will be exposed to the challenge virus on study day 0. Cohort 1 will receive either 200 mg of sisunatovir or placebo (looks the same as sisunatovir but contains no active medicine) 2 times a day for 5 days. Cohort 2 will receive either 350 mg of sisunatovir or placebo 2 times a day for 5 days. Participants will start taking the study medicine upon confirmation of RSV infection (or evening of Day 5 if not positive to RSV). The study medicine will be administered 12 hours apart (or twice daily). Each participant will remain in the quarantine unit until discharge on Day 12.
- Conditions
- Respiratory Syncytial Virus Infections
- Being tested
- RV521, Placebo
- Medical subject headings
- Respiratory Syncytial Virus Infections
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
RV521Drug
RV521 drug in capsules
PlaceboDrug
Placebo in capsules
| Study group | Role | What they receive |
|---|---|---|
| RV521 | Experimental | RV521 drug substance in capsule for oral administration Receives: Drug: RV521 |
| Placebo | Placebo comparator | Micro-crystalline cellulose in capsule for oral administration Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in viral load
Measured: Baseline to study day 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Aug 2017
- Study start19 Jul 2017
- Primary completion31 Oct 2017
- Study completion31 Oct 2017
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Respiratory Syncytial Virus InfectionsStudies of the same condition, open and under way.
- More trials run by PfizerThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 66 participants (actual)
Sponsor and investigators
- Lead sponsor
- Pfizer
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Pfizer CT.gov Call Center, Study director, Pfizer
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT03258502
- Sponsor's protocol ID
- REVC002
- Other IDs
- C5241002
- Status last verified
- Jul 2025
- First submitted
- 15 Aug 2017
- Last updated
- 31 Jul 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical\_trials/trial\_data\_and\_results/data\_requests.
Publications
DeVincenzo J, Tait D, Efthimiou J, Mori J, Kim YI, Thomas E, Wilson L, Harland R, Mathews N, Cockerill S, Powell K, Littler E. A Randomized, Placebo-Controlled, Respiratory Syncytial Virus Human Challenge Study of the Antiviral Efficacy, Safety, and Pharmacokinetics of RV521, an Inhibitor of the RSV-F Protein. Antimicrob Agents Chemother. 2020 Jan 27;64(2):e01884-19. doi: 10.1128/AAC.01884-19. Print 2020 Jan 27.
PubMed 31712214
Study at a glance
From the registry record, last updated by the sponsor on 31 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomised, Phase 2a, Double-Blind, Placebo-Controlled Study To Evaluate The Safety, Pharmacokinetics And Antiviral Activity Of Multiple Doses Of RV521 Against Respiratory Syncytial Virus Infection In The Virus Challenge Model
- ClinicalTrials.gov ID
- NCT03258502
- Acronym / sponsor ID
- REVC002
- Conditions
- Respiratory Syncytial Virus Infections
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 66 participants (actual)
- Lead sponsor
- PfizerIndustry (pharma, biotech, devices)
- Study start
- 19 Jul 2017 (actual)
- Primary completion
- 31 Oct 2017 (actual)
- Study completion
- 31 Oct 2017 (actual)
- First posted
- 23 Aug 2017 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of the study is to learn about the safety, pharmacokinetics and antiviral activity of the study medicine (called sisunatovir/RV521) for the potential treatment of respiratory syncytial virus (RSV). Sisunatovir will be given as multiple doses during the treatment period. RSV is a highly contagious virus that can lead to serious lung infections in patients with reduced ability to fight infection. Most vulnerable populations include babies, the elderly and patients that have received a bone marrow transplant.
This study is seeking healthy participants who are:
- Aged 18 to 45 years old and will agree to the use of highly effective methods of contraception.
- with a body mass index (BMI) of 18.0 to 30.0 Kg/m2 This study will consist of 2 cohorts of 33 participants each. In both cohorts participants will be exposed to the challenge virus on study day 0. Cohort 1 will receive either 200 mg of sisunatovir or placebo (looks the same as sisunatovir but contains no active medicine) 2 times a day for 5 days. Cohort 2 will receive either 350 mg of sisunatovir or placebo 2 times a day for 5 days. Participants will start taking the study medicine upon confirmation of RSV infection (or evening of Day 5 if not positive to RSV). The study medicine will be administered 12 hours apart (or twice daily). Each participant will remain in the quarantine unit until discharge on Day 12.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| RV521 | Experimental | Drug: RV521RV521 drug substance in capsule for oral administration |
| Placebo | Placebo comparator | Drug: PlaceboMicro-crystalline cellulose in capsule for oral administration |
Who may qualify
- Ages
- 18 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Age 18 to 45 years, inclusive
- In good health with no history of major medical conditions
- A total body weight ≥ 50 kg and a body mass index (BMI) of >/=18kg/m2 and </=30kg/m2
Key exclusion criteria (5 listed)
- Evidence of any clinically significant or currently active major medical condition
- Positive for Human Immunodeficiency Virus, active Hepatitis A, B or C test
- Significant nose or nasopharynx abnormalities
- Abnormal lung function
- History or currently active symptoms suggestive of upper or lower respiratory tract infection
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| RV521RV521 drug in capsules | Drug | RV521 |
| PlaceboPlacebo in capsules | Drug | Placebo |
Primary outcome
Change in viral load
Time frame: Baseline to study day 12
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 31 Jul 2025.
- Derived from this study: PubMed 31712214DeVincenzo J, Tait D, Efthimiou J, Mori J, Kim YI, Thomas E, Wilson L, Harland R, Mathews N, Cockerill S, Powell K, Littler E. A Randomized, Placebo-Controlled, Respiratory Syncytial Virus Human Challenge Study of the Antiviral Efficacy, Safety, and Pharmacokinetics of RV521, an Inhibitor of the RSV-F Protein. Antimicrob Agents Chemother. 2020 Jan 27;64(2):e01884-19. doi: 10.1128/AAC.01884-19. Print 2020 Jan 27.
- To obtain contact information for a study center near you, click here.Link provided by the sponsor.
- Individual participant dataSharing planned: Yes. Pfizer will provide access to individual de-identified participant data and related study documents (e.g. protocol, Statistical Analysis Plan (SAP), Clinical Study Report (CSR)) upon request from qualified researchers, and subject to certain criteria, conditions, and exceptions. Further details on Pfizer's data sharing criteria and process for requesting access can be found at: https://www.pfizer.com/science/clinical_trials/trial_data_and_results/data_requests.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Pfizer CT.gov Call Center study director
Pfizer
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing RV521 in people with Respiratory Syncytial Virus Infections, run by Pfizer at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 31 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in viral load (time frame: Baseline to study day 12). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT03258502, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 31 Jul 2025; AzTrials last refreshed its copy on 31 Oct 2026.